The forbidden TRUTH
- Thread starter ghostdriver
- Start date
Ceepea
Well-Known Member
You made an assumption and based your entire argument off that assumption. Not to mention, you didn't even do a good job at it.
Your argument hardly comes to a factual conclusion.
What I posted was your conclusion summed up.
ghostdriver
Well-Known Member
I have so much to post I can't explain. Explaining why LORD JESUS CHRIST came when he did near the end and how LORD JESUS CHRIST is connected with them. And how LORD JESUS CHRIST was with GOD before creation and how GOD created the creation through his Son. (If you only knew how important and blessed mankind is)
It will contain a lot of information, with pictures and videos. But it's going to take a long time to post might even have to do it in sessions. But for now enjoy this interesting miracles and wonders! Also I know these "locals in this section" (whom I haven't ever spoken to prior posting this thread) will be saying cursing and blaspheme claiming this isn't proof. I would like to say in advanced I have proven your'e darwin's Cult wrong, and no matter how devote of a follower you are posting mean spiteful and blasphemous things will not sway anyone to your religion, nor upset me. So I already proved how your religion has no evidence, and saying GOD didn't do what he did by creating existence. Which is ignorant because your only thing you call "evidence" that you think suggest your'e religion I explained it's impossible because we know "matter" can't create "matter" and then you said what I'm telling you as a fact is contradicting it's self and I proved you wrong and explained and even copy and pasted multiple times
"You think because GOD ALMIGHTY is the beginning and the end, you can state that the universe can be the same because it's following the same principal? That's completely erroneous. The only reason GOD is before everything is because GOD is a living omnipotent being that you cannot fathom. Before the beginning GOD was."- page 43 Matter lacks the ability to create something from nothing.
So yes this is "proof" however I'm posting it because I would like people to see miracles and wonders that GOD does and has done.
What a awesome reminder of HIS power!
Again only microscopic in size instead of the giant sign above, yet the awesomeness is still so baffling.
-------> http://www.google.com/imgres?imgurl=https://cdn-assets.answersingenesis.org/img/articles/aid/v3/laminin.gif&imgrefurl=https://answersingenesis.org/biology/microbiology/laminin-and-the-cross/&h=279&w=180&tbnid=YJhFSDA1MCQkwM:&zoom=1&tbnh=186&tbnw=120&usg=__jEdhEi9Sqyo-cc5HG8FEzZWFPPA=&docid=2L_Y205OhAzLJM&itg=1&sa=X&ei=xCGMU7-LFOrlsATtwYDADQ&sqi=2&ved=0CJIBEPwdMAo
Info of Laminin below
http://en.wikipedia.org/wiki/Laminin <-----
See my testimony's at page forty, here is another someone you all may recognize I know none of you know me. (that I know of LOL)
Had to re-post because of spam, enjoy your night! Love you guys! Hope you all bow and kneel before GOD and beg for mercy through the Son LORD JESUS CHRIST. And beg to be accepted by the mighty sacrifice that has taken place for you to enter in the Kingdom of heaven with THE MOST HOLY MAJESTY ALPHA AND OMEGA.
It will contain a lot of information, with pictures and videos. But it's going to take a long time to post might even have to do it in sessions. But for now enjoy this interesting miracles and wonders! Also I know these "locals in this section" (whom I haven't ever spoken to prior posting this thread) will be saying cursing and blaspheme claiming this isn't proof. I would like to say in advanced I have proven your'e darwin's Cult wrong, and no matter how devote of a follower you are posting mean spiteful and blasphemous things will not sway anyone to your religion, nor upset me. So I already proved how your religion has no evidence, and saying GOD didn't do what he did by creating existence. Which is ignorant because your only thing you call "evidence" that you think suggest your'e religion I explained it's impossible because we know "matter" can't create "matter" and then you said what I'm telling you as a fact is contradicting it's self and I proved you wrong and explained and even copy and pasted multiple times
"You think because GOD ALMIGHTY is the beginning and the end, you can state that the universe can be the same because it's following the same principal? That's completely erroneous. The only reason GOD is before everything is because GOD is a living omnipotent being that you cannot fathom. Before the beginning GOD was."- page 43 Matter lacks the ability to create something from nothing.
So yes this is "proof" however I'm posting it because I would like people to see miracles and wonders that GOD does and has done.
What a awesome reminder of HIS power!
Again only microscopic in size instead of the giant sign above, yet the awesomeness is still so baffling.
-------> http://www.google.com/imgres?imgurl=https://cdn-assets.answersingenesis.org/img/articles/aid/v3/laminin.gif&imgrefurl=https://answersingenesis.org/biology/microbiology/laminin-and-the-cross/&h=279&w=180&tbnid=YJhFSDA1MCQkwM:&zoom=1&tbnh=186&tbnw=120&usg=__jEdhEi9Sqyo-cc5HG8FEzZWFPPA=&docid=2L_Y205OhAzLJM&itg=1&sa=X&ei=xCGMU7-LFOrlsATtwYDADQ&sqi=2&ved=0CJIBEPwdMAo
Info of Laminin below
http://en.wikipedia.org/wiki/Laminin <-----
See my testimony's at page forty, here is another someone you all may recognize I know none of you know me. (that I know of LOL)
Had to re-post because of spam, enjoy your night! Love you guys! Hope you all bow and kneel before GOD and beg for mercy through the Son LORD JESUS CHRIST. And beg to be accepted by the mighty sacrifice that has taken place for you to enter in the Kingdom of heaven with THE MOST HOLY MAJESTY ALPHA AND OMEGA.
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Dislexicmidget2021
Well-Known Member
Sorry about that,
Ceepea
Well-Known Member
Ghost, you have to show rational people that god exists before they're going to go along with your silly group think.
No person who has natural or learned critical thinking ability will give you the time of day.
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ghostdriver
Well-Known Member
Everything you just posted states that the body of humans and creatures have the ability to be acclimated which was the starting point of darwins theory. There is no proof that human beings come from bacteria or any creature ever. I'm sure you got excited at this misleading presentation but read what you posted. Your'e saying that I said animals and human beings flesh are not similar, they are very similar in someways but our soul is nothing like theirs. I'm not asking you to prove survival of the fittest ether, which this mentions, or how animals belonging to the same gene pool can mate with other animals making adaptions to their body. All dogs and cats are mixed breeds, and different nationalities have different traits skin, eyes, face ect. That change based on your partner in your gene pool. Our skin and body also will become more resilient to sun, or weather the longer we endure it. GOD's creation is awesome. Darwins theory is that this proves his theory. I already knew this. I know what your religion believes, this is what you think of as holy scripture. Now where is the proof that
germs=Human beings
germs= made creation matter and light
germs made germs or germs have always been. Matter can't create mater unless it's THE ALMIGHTY OMNIPOTENT GOD
I will begin to ask you questions knowing the answer to prove your religion is wrong if you want me too. But you said you have proof I know what you think but I want your proof. This is like a islam man posting Qu'ran saying "this this is proof!" I would tell him the same thing i'm telling you this isn't proof this is your theory I already knew your blasphemous cult theory. I would then ask for proof again so where is all your proof you speak of? (asking knowing the answer because I am a witness of GOD) Then if you want I can begin to ask you questions ( knowing the answers) to have blatantly show you the irrational and obscure view your'e being tricked into.
- Post 804 answering your post 803
Response to your post not liking this post
And Claiming all creatures are built a certain way to swim, run, fly ect. is clearly proof of GOD not that bacteria are constantly trying to evolve into human beings with the ability also to be monkeys, elephants, giraffe, ect. lol this is a horrible blaspheme theory based on the noticing how animals are all built in a certain way to pertaining to how they live? So instead realizing GOD made everything the way it is for a reason stars, sun, earth temp, earth spin, all the animals and your fingers and toes, body ect. Your religion says "that's impossible you have never seen that happened so believe something else you have never seen that people and animals constantly evolve from bacteria and we don't know anything else but this is right we are positive, and even though there is no bacteria forming into creatures or humans or anything in which would EVER suggest this, we have no evidence at all for this idea, but because all the other options are wrong because we say science doesn't support that a being can create things, because we haven't seen it.? Well science says your'e wrong because batter can't create something from nothing, Only THE CREATOR GOD can.
germs=Human beings
germs= made creation matter and light
germs made germs or germs have always been. Matter can't create mater unless it's THE ALMIGHTY OMNIPOTENT GOD
I will begin to ask you questions knowing the answer to prove your religion is wrong if you want me too. But you said you have proof I know what you think but I want your proof. This is like a islam man posting Qu'ran saying "this this is proof!" I would tell him the same thing i'm telling you this isn't proof this is your theory I already knew your blasphemous cult theory. I would then ask for proof again so where is all your proof you speak of? (asking knowing the answer because I am a witness of GOD) Then if you want I can begin to ask you questions ( knowing the answers) to have blatantly show you the irrational and obscure view your'e being tricked into.
- Post 804 answering your post 803
Response to your post not liking this post
And Claiming all creatures are built a certain way to swim, run, fly ect. is clearly proof of GOD not that bacteria are constantly trying to evolve into human beings with the ability also to be monkeys, elephants, giraffe, ect. lol this is a horrible blaspheme theory based on the noticing how animals are all built in a certain way to pertaining to how they live? So instead realizing GOD made everything the way it is for a reason stars, sun, earth temp, earth spin, all the animals and your fingers and toes, body ect. Your religion says "that's impossible you have never seen that happened so believe something else you have never seen that people and animals constantly evolve from bacteria and we don't know anything else but this is right we are positive, and even though there is no bacteria forming into creatures or humans or anything in which would EVER suggest this, we have no evidence at all for this idea, but because all the other options are wrong because we say science doesn't support that a being can create things, because we haven't seen it.? Well science says your'e wrong because batter can't create something from nothing, Only THE CREATOR GOD can.
ghostdriver
Well-Known Member
Every marine Biologist knows what the Hen bone is and what it's used for it's not legs. It's a pelvic bone designed by GOD
http://www.trueorigin.org/ng_whales01.asp Doesn't list speculation it's listing facts
http://en.wikipedia.org/wiki/Pakicetus is very clear that some people THINK that, but that's not based off evidence.
Pakicetus is an extinct genus of amphibious cetacean of the family Pakicetidae which was endemic to the Eocene of Pakistan.[1]The vast majority of paleontologists regard it as the most basal whale.
-If this was fact with real evidence all paleontologist would agree.
Pakicetus was originally described as being a mesonychid, but later research reclassified it as an early cetacean due to characteristic features of the inner ear found only incetaceans; namely, the large auditory bulla is formed from the ectotympanicbone only. It was then believed to be descended from mesonychids, according to Gingerich & Russell 1981. However, the redescription of the primitive, semi-aquatic artiodactyl Indohyus, and the discovery of its cetacean-like inner ear simultaneously put an end to the idea that whales were descended from mesonychids, while demonstrating that Pakicetus, and all other cetaceans, are artiodactyls. Thus, Pakicetus represents a transitional taxon between extinct land mammals and modern cetaceans.[4]
- Gingerich again but then corrects himself when he finds what he calls "new evidence" LOL
-Gingerich also from the 2001 November issue on the walking whales LOL which
It was illustrated on the cover of Science as a semiaquatic, vaguely crocodilelike mammal, diving after fish.[5]
- LOL completely not what it looks like on wikipedia
Somewhat more complete skeletal remains were discovered in 2001, prompting the view that Pakicetus was primarily a land animal about the size of a wolf, and very similar in form to the related mesonychids. Thewissen et al. 2001 wrote that "Pakicetids were terrestrial mammals, no more amphibious than a tapir."[6]
However, Thewissen et al. 2009 argued that "the orbits ... of these cetaceans were located close together on top of the skull, as is common in aquatic animals that live in water but look at emerged objects. Just like Indohyus, limb bones of pakicetids areosteosclerotic, also suggestive of aquatic habitat"[7] (since heavy bones provide ballast). "This peculiarity could indicate thatPakicetus could stand in water, almost totally immersed, without losing visual contact with the air."[8]
The Pakicetus skeleton reveals several details regarding the creature's unique senses, and provides a newfound ancestral link between terrestrial and aquatic animals. As previously mentioned, the Pakicetus' upward-facing eye placement was a significant indication of its habitat. Even more so, however, was its auditory abilities. Like all other cetaceans, Pakicetus had a thickened skull bone known as the auditory bulla, which was specialized for underwater hearing.[9] Cetaceans also all categorically exhibit a large mandibular foramen within the lower jaw, which holds a fat pack and extends towards the ear, both of which are also associated with underwater hearing. "Pakicetus is the only cetacean in which the mandibular foramen is small, as is the case in all terrestrial animals. It thus lacked the fat pad, and sounds reached its eardrum following the external auditory meatus as in terrestrial mammals. Thus the hearing mechanism of Pakicetus is the only known intermediate between that of land mammals and aquatic cetaceans."[10]With both the auditory and visual senses in mind, as well as the typical diet of Pakicetus, one might assume the creature was able to attack both aquatic and terrestrial prey from a low vantage point.
- Your basically reading this and thinking because this creature isn't just like another one, it's got to be in the middle of it evolving phase LOL
None of the features in question are any evidence of an evolutionary relationship. Even evolutionists admit that most of the theoretical relationships built on the basis of anatomical similarities between animals are completely untrustworthy. If the marsupial Tasmanian wolf and the common placental wolf had both been extinct for a long time, then it is no doubt that evolutionists would picture them in the same taxon and define them as very close relatives. However, we know that these two different animals, although strikingly similar in their anatomy, are very far from each other in the supposed evolutionary tree of life. (In fact their similarity indicates common design—not common descent.) Pakicetus, which National Geographicdeclared to be a ‘walking whale,’ was a unique species harboring different features in its body. In fact, Carroll, an authority on vertebrate paleontology, describes the Mesonychid family, of whichPakicetus should be a member, as “exhibiting an odd combination of characters.”[3] Such prominent evolutionists as Gould accept that ‘mosaic creatures’ of this type cannot be considered as transitional forms.
Do you think the duck billed platypus turning into a complete duck?
So your'e saying GOD can't create creation and has always been? but the Universe can create and has always been? That's literally believing in something that you claim is impossible.
"You think because GOD ALMIGHTY is the beginning and the end, you can state that the universe can be the same because it's following the same principal? That's completely erroneous. The only reason GOD is before everything is because GOD is a living omnipotent being that you cannot fathom. Before the beginning GOD was."- page 43
http://www.trueorigin.org/ng_whales01.asp Doesn't list speculation it's listing facts
http://en.wikipedia.org/wiki/Pakicetus is very clear that some people THINK that, but that's not based off evidence.
Pakicetus is an extinct genus of amphibious cetacean of the family Pakicetidae which was endemic to the Eocene of Pakistan.[1]The vast majority of paleontologists regard it as the most basal whale.
-If this was fact with real evidence all paleontologist would agree.
Pakicetus was originally described as being a mesonychid, but later research reclassified it as an early cetacean due to characteristic features of the inner ear found only incetaceans; namely, the large auditory bulla is formed from the ectotympanicbone only. It was then believed to be descended from mesonychids, according to Gingerich & Russell 1981. However, the redescription of the primitive, semi-aquatic artiodactyl Indohyus, and the discovery of its cetacean-like inner ear simultaneously put an end to the idea that whales were descended from mesonychids, while demonstrating that Pakicetus, and all other cetaceans, are artiodactyls. Thus, Pakicetus represents a transitional taxon between extinct land mammals and modern cetaceans.[4]
- Gingerich again but then corrects himself when he finds what he calls "new evidence" LOL
-Gingerich also from the 2001 November issue on the walking whales LOL which
It was illustrated on the cover of Science as a semiaquatic, vaguely crocodilelike mammal, diving after fish.[5]
- LOL completely not what it looks like on wikipedia
Somewhat more complete skeletal remains were discovered in 2001, prompting the view that Pakicetus was primarily a land animal about the size of a wolf, and very similar in form to the related mesonychids. Thewissen et al. 2001 wrote that "Pakicetids were terrestrial mammals, no more amphibious than a tapir."[6]
However, Thewissen et al. 2009 argued that "the orbits ... of these cetaceans were located close together on top of the skull, as is common in aquatic animals that live in water but look at emerged objects. Just like Indohyus, limb bones of pakicetids areosteosclerotic, also suggestive of aquatic habitat"[7] (since heavy bones provide ballast). "This peculiarity could indicate thatPakicetus could stand in water, almost totally immersed, without losing visual contact with the air."[8]
The Pakicetus skeleton reveals several details regarding the creature's unique senses, and provides a newfound ancestral link between terrestrial and aquatic animals. As previously mentioned, the Pakicetus' upward-facing eye placement was a significant indication of its habitat. Even more so, however, was its auditory abilities. Like all other cetaceans, Pakicetus had a thickened skull bone known as the auditory bulla, which was specialized for underwater hearing.[9] Cetaceans also all categorically exhibit a large mandibular foramen within the lower jaw, which holds a fat pack and extends towards the ear, both of which are also associated with underwater hearing. "Pakicetus is the only cetacean in which the mandibular foramen is small, as is the case in all terrestrial animals. It thus lacked the fat pad, and sounds reached its eardrum following the external auditory meatus as in terrestrial mammals. Thus the hearing mechanism of Pakicetus is the only known intermediate between that of land mammals and aquatic cetaceans."[10]With both the auditory and visual senses in mind, as well as the typical diet of Pakicetus, one might assume the creature was able to attack both aquatic and terrestrial prey from a low vantage point.
- Your basically reading this and thinking because this creature isn't just like another one, it's got to be in the middle of it evolving phase LOL
None of the features in question are any evidence of an evolutionary relationship. Even evolutionists admit that most of the theoretical relationships built on the basis of anatomical similarities between animals are completely untrustworthy. If the marsupial Tasmanian wolf and the common placental wolf had both been extinct for a long time, then it is no doubt that evolutionists would picture them in the same taxon and define them as very close relatives. However, we know that these two different animals, although strikingly similar in their anatomy, are very far from each other in the supposed evolutionary tree of life. (In fact their similarity indicates common design—not common descent.) Pakicetus, which National Geographicdeclared to be a ‘walking whale,’ was a unique species harboring different features in its body. In fact, Carroll, an authority on vertebrate paleontology, describes the Mesonychid family, of whichPakicetus should be a member, as “exhibiting an odd combination of characters.”[3] Such prominent evolutionists as Gould accept that ‘mosaic creatures’ of this type cannot be considered as transitional forms.
Do you think the duck billed platypus turning into a complete duck?
So your'e saying GOD can't create creation and has always been? but the Universe can create and has always been? That's literally believing in something that you claim is impossible.
"You think because GOD ALMIGHTY is the beginning and the end, you can state that the universe can be the same because it's following the same principal? That's completely erroneous. The only reason GOD is before everything is because GOD is a living omnipotent being that you cannot fathom. Before the beginning GOD was."- page 43
ghostdriver
Well-Known Member
Praise THE LORD
ghostdriver
Well-Known Member
http://www.google.com/imgres?imgurl=https://cdn-assets.answersingenesis.org/img/articles/aid/v3/laminin.gif&imgrefurl=https://answersingenesis.org/biology/microbiology/laminin-and-the-cross/&h=279&w=180&tbnid=YJhFSDA1MCQkwM:&zoom=1&tbnh=186&tbnw=120&usg=__jEdhEi9Sqyo-cc5HG8FEzZWFPPA=&docid=2L_Y205OhAzLJM&itg=1&sa=X&ei=xCGMU7-LFOrlsATtwYDADQ&sqi=2&ved=0CJIBEPwdMAo
http://en.wikipedia.org/wiki/Laminin
I updated this picture in the post above,
illuminati just took the picture down on the heading on wikipedia
http://en.wikipedia.org/wiki/Laminin
I updated this picture in the post above,
illuminati just took the picture down on the heading on wikipedia
Dislexicmidget2021
Well-Known Member
Oh the illuminati took it down? that truly explains everything,,,,
The reynolds wrap company just called and said you owe them alot of money.Your tinfoil hat conspiracy group is taking up all of the stock.You think that the cross shape laminen protein is proof that supports your point of view, simply because of its molecular shape.While a line from biblical scripture coincides conveniently with your perception on this subject only to further dilude you into that bias assumption.
It is true that you carry a prejudgement to all things you can possibly lay eye upon in life,its apparent you view that everything must involve your creator and that you harbor a habitual zero tolerance of any other thought process not involving your god,when in reality you do not know as you claim to .<This is what you are showing everyone here,with all of the scripture and circular logic you do exhibit.
The fact that you post an already biased source of information about the laminen protein only further shows your logical dispostion.
Scientific study's have shown what laminen is.There is a good amount of data on its properites and how it benefits us anatomicaly.
No scientific record or study has indicated in the slightest, a correlation of the cross like shape of laminen to be linked to some biblical truth or to have given any credibility to the existence of any god.The cross like shape and what so many think it to be,( mostly religious individuals view it as a sign of "Gods fingerprint") is nothing more than subjective speculation and HAS NOT BEEN PROVEN.
It isnt actualy a sign of any kind but an observation within the extracellular matrix showing laminen to be one of the glues holding cellular structures together.
Another biblical lecture is on its way,Yet it will prove that you are stuck in an illogical way of thinking.
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ghostdriver
Well-Known Member
It will contain a lot of information, with pictures and videos. But it's going to take a long time to post might even have to do it in sessions. But for now enjoy this interesting miracles and wonders! Also I know these "locals in this section" (whom I haven't ever spoken to prior posting this thread) will be saying cursing and blaspheme claiming this isn't proof. I would like to say in advanced I have proven your'e darwin's Cult wrong, and no matter how devote of a follower you are posting mean spiteful and blasphemous things will not sway anyone to your religion, nor upset me. So I already proved how your religion has no evidence, and saying GOD didn't do what he did by creating existence. Which is ignorant because your only thing you call "evidence" that you think suggest your'e religion I explained it's impossible because we know "matter" can't create "matter" and then you said what I'm telling you as a fact is contradicting it's self and I proved you wrong and explained and even copy and pasted multiple times
-post 963
-post 963
Ceepea
Well-Known Member
Evidence of common descent of living things has been discovered by scientists working in a variety of fields over many years. This evidence has demonstrated and verified the occurrence of evolution and provided a wealth of information on the natural processes by which the variety and diversity of life on Earth developed. This evidence supports the modern evolutionary synthesis, the current scientific theory that explains how and why life changes over time. Evolutionary biologists document evidence of common descent: making testable predictions, testing hypotheses, and developing theories that illustrate and describe its causes.
Comparison of the DNA genetic sequences of organisms has revealed that organisms that are phylogenetically close have a higher degree of DNA sequence similarity than organisms that are phylogenetically distant. Further evidence for common descent comes from genetic detritus such as pseudogenes, regions of DNA that are orthologous to a gene in a related organism, but are no longer active and appear to be undergoing a steady process of degeneration from cumulative mutations.
Fossils are important for estimating when various lineages developed in geologic time. As fossilization is an uncommon occurrence, usually requiring hard body parts and death near a site where sediments are being deposited, the fossil record only provides sparse and intermittent information about the evolution of life. Evidence of organisms prior to the development of hard body parts such as shells, bones and teeth is especially scarce, but exists in the form of ancient microfossils, as well as impressions of various soft-bodied organisms. The comparative study of the anatomy of groups of animals shows structural features that are fundamentally similar or homologous, demonstrating phylogenetic and ancestral relationships with other organisms, most especially when compared with fossils of ancient extinct organisms. Vestigial structures and comparisons in embryonic development are largely a contributing factor in anatomical resemblance in concordance with common descent. Since metabolic processes do not leave fossils, research into the evolution of the basic cellular processes is done largely by comparison of existing organisms’ physiology and biochemistry. Many lineages diverged at different stages of development, so it is possible to determine when certain metabolic processes appeared by comparing the traits of the descendants of a common ancestor. Universal biochemical organization and molecular variance patterns in all organisms also show a direct correlation with common descent.
Further evidence comes from the field of biogeography because evolution with common descent provides the best and most thorough explanation for a variety of facts concerning the geographical distribution of plants and animals across the world. This is especially obvious in the field of island biogeography. Combined with the theory of plate tectonics common descent provides a way to combine facts about the current distribution of species with evidence from the fossil record to provide a logically consistent explanation of how the distribution of living organisms has changed over time.
The development and spread of antibiotic resistant bacteria, like the spread of pesticide resistant forms of plants and insects provides evidence that evolution due to natural selection is an ongoing process in the natural world. Alongside this, are observed instances of the separation of populations of species into sets of new species (speciation). Speciation has been observed directly and indirectly in the lab and in nature. Multiple forms of such have been described and documented as examples for individual modes of speciation. Furthermore, evidence of common descent extends from direct laboratory experimentation with the artificial selection of organisms—historically and currently—and other controlled experiments involving many of the topics in the article. This article explains the different types of evidence for evolution with common descent along with many specialized examples of each.
Ceepea
Well-Known Member
Evidence from comparative physiology and biochemistry
See also: Archaeogenetics, Common descent, Last universal ancestor, Most recent common ancestor, Timeline of evolution, Timeline of human evolution and Universal Code (Biology)
Genetics
While on board HMS Beagle, Charles Darwin collected numerous specimens, many new to science, which supported his later theory of evolution by natural selection.
One of the strongest evidences for common descent comes from the study of gene sequences. Comparative sequence analysis examines the relationship between the DNA sequences of different species,[1] producing several lines of evidence that confirm Darwin's original hypothesis of common descent. If the hypothesis of common descent is true, then species that share a common ancestor inherited that ancestor's DNA sequence, as well as mutations unique to that ancestor. More closely related species have a greater fraction of identical sequence and shared substitutions compared to more distantly related species.
The simplest and most powerful evidence is provided by phylogenetic reconstruction. Such reconstructions, especially when done using slowly evolving protein sequences, are often quite robust and can be used to reconstruct a great deal of the evolutionary history of modern organisms (and even in some instances of the evolutionary history of extinct organisms, such as the recovered gene sequences of mammoths or Neanderthals). These reconstructed phylogenies recapitulate the relationships established through morphological and biochemical studies. The most detailed reconstructions have been performed on the basis of the mitochondrial genomes shared by all eukaryotic organisms, which are short and easy to sequence; the broadest reconstructions have been performed either using the sequences of a few very ancient proteins or by using ribosomal RNA sequence.
Phylogenetic relationships also extend to a wide variety of nonfunctional sequence elements, including repeats, transposons, pseudogenes, and mutations in protein-coding sequences that do not result in changes in amino-acid sequence. While a minority of these elements might later be found to harbor function, in aggregate they demonstrate that identity must be the product of common descent rather than common function.
Universal biochemical organisation and molecular variance patterns
All known extant (surviving) organisms are based on the same biochemical processes: genetic information encoded as nucleic acid (DNA, or RNA for many viruses), transcribed into RNA, then translated into proteins (that is, polymers of amino acids) by highly conserved ribosomes. Perhaps most tellingly, the Genetic Code (the "translation table" between DNA and amino acids) is the same for almost every organism, meaning that a piece of DNA in a bacterium codes for the same amino acid as in a human cell. ATP is used as energy currency by all extant life. A deeper understanding of developmental biology shows that common morphology is, in fact, the product of shared genetic elements.[2] For example, although camera-like eyes are believed to have evolved independently on many separate occasions,[3] they share a common set of light-sensing proteins (opsins), suggesting a common point of origin for all sighted creatures.[4][5] Another noteworthy example is the familiar vertebrate body plan, whose structure is controlled by the homeobox (Hox) family of genes.
DNA sequencing
Comparison of the DNA sequences allows organisms to be grouped by sequence similarity, and the resulting phylogenetic trees are typically congruent with traditional taxonomy, and are often used to strengthen or correct taxonomic classifications. Sequence comparison is considered a measure robust enough to correct erroneous assumptions in the phylogenetic tree in instances where other evidence is scarce. For example, neutral human DNA sequences are approximately 1.2% divergent (based on substitutions) from those of their nearest genetic relative, the chimpanzee, 1.6% from gorillas, and 6.6% from baboons.[6][7] Genetic sequence evidence thus allows inference and quantification of genetic relatedness between humans and other apes.[8][9] The sequence of the 16S ribosomal RNA gene, a vital gene encoding a part of the ribosome, was used to find the broad phylogenetic relationships between all extant life. The analysis, originally done by Carl Woese, resulted in the three-domain system, arguing for two major splits in the early evolution of life. The first split led to modern Bacteria and the subsequent split led to modern Archaea and Eukaryotes.
Some DNA sequences are shared by very different organisms. It has been predicted by the theory of evolution that the differences in such DNA sequences between two organisms should roughly resemble both the biological difference between them according to their anatomy and the time that had passed since these two organisms have separated in the course of evolution, as seen in fossil evidence. The rate of accumulating such changes should be low for some sequences, namely those that code for critical RNA or proteins, and high for others that code for less critical RNA or proteins; but for every specific sequence, the rate of change should be roughly constant over time. These results have been experimentally confirmed. Two examples are DNA sequences coding for rRNA, which is highly conserved, and DNA sequences coding for fibrinopeptides (amino acid chains that are discarded during the formation of fibrin), which are highly non-conserved.[10]
Endogenous retroviruses
See also: Archaeogenetics, Common descent, Last universal ancestor, Most recent common ancestor, Timeline of evolution, Timeline of human evolution and Universal Code (Biology)
Genetics
While on board HMS Beagle, Charles Darwin collected numerous specimens, many new to science, which supported his later theory of evolution by natural selection.
One of the strongest evidences for common descent comes from the study of gene sequences. Comparative sequence analysis examines the relationship between the DNA sequences of different species,[1] producing several lines of evidence that confirm Darwin's original hypothesis of common descent. If the hypothesis of common descent is true, then species that share a common ancestor inherited that ancestor's DNA sequence, as well as mutations unique to that ancestor. More closely related species have a greater fraction of identical sequence and shared substitutions compared to more distantly related species.
The simplest and most powerful evidence is provided by phylogenetic reconstruction. Such reconstructions, especially when done using slowly evolving protein sequences, are often quite robust and can be used to reconstruct a great deal of the evolutionary history of modern organisms (and even in some instances of the evolutionary history of extinct organisms, such as the recovered gene sequences of mammoths or Neanderthals). These reconstructed phylogenies recapitulate the relationships established through morphological and biochemical studies. The most detailed reconstructions have been performed on the basis of the mitochondrial genomes shared by all eukaryotic organisms, which are short and easy to sequence; the broadest reconstructions have been performed either using the sequences of a few very ancient proteins or by using ribosomal RNA sequence.
Phylogenetic relationships also extend to a wide variety of nonfunctional sequence elements, including repeats, transposons, pseudogenes, and mutations in protein-coding sequences that do not result in changes in amino-acid sequence. While a minority of these elements might later be found to harbor function, in aggregate they demonstrate that identity must be the product of common descent rather than common function.
Universal biochemical organisation and molecular variance patterns
All known extant (surviving) organisms are based on the same biochemical processes: genetic information encoded as nucleic acid (DNA, or RNA for many viruses), transcribed into RNA, then translated into proteins (that is, polymers of amino acids) by highly conserved ribosomes. Perhaps most tellingly, the Genetic Code (the "translation table" between DNA and amino acids) is the same for almost every organism, meaning that a piece of DNA in a bacterium codes for the same amino acid as in a human cell. ATP is used as energy currency by all extant life. A deeper understanding of developmental biology shows that common morphology is, in fact, the product of shared genetic elements.[2] For example, although camera-like eyes are believed to have evolved independently on many separate occasions,[3] they share a common set of light-sensing proteins (opsins), suggesting a common point of origin for all sighted creatures.[4][5] Another noteworthy example is the familiar vertebrate body plan, whose structure is controlled by the homeobox (Hox) family of genes.
DNA sequencing
Comparison of the DNA sequences allows organisms to be grouped by sequence similarity, and the resulting phylogenetic trees are typically congruent with traditional taxonomy, and are often used to strengthen or correct taxonomic classifications. Sequence comparison is considered a measure robust enough to correct erroneous assumptions in the phylogenetic tree in instances where other evidence is scarce. For example, neutral human DNA sequences are approximately 1.2% divergent (based on substitutions) from those of their nearest genetic relative, the chimpanzee, 1.6% from gorillas, and 6.6% from baboons.[6][7] Genetic sequence evidence thus allows inference and quantification of genetic relatedness between humans and other apes.[8][9] The sequence of the 16S ribosomal RNA gene, a vital gene encoding a part of the ribosome, was used to find the broad phylogenetic relationships between all extant life. The analysis, originally done by Carl Woese, resulted in the three-domain system, arguing for two major splits in the early evolution of life. The first split led to modern Bacteria and the subsequent split led to modern Archaea and Eukaryotes.
Some DNA sequences are shared by very different organisms. It has been predicted by the theory of evolution that the differences in such DNA sequences between two organisms should roughly resemble both the biological difference between them according to their anatomy and the time that had passed since these two organisms have separated in the course of evolution, as seen in fossil evidence. The rate of accumulating such changes should be low for some sequences, namely those that code for critical RNA or proteins, and high for others that code for less critical RNA or proteins; but for every specific sequence, the rate of change should be roughly constant over time. These results have been experimentally confirmed. Two examples are DNA sequences coding for rRNA, which is highly conserved, and DNA sequences coding for fibrinopeptides (amino acid chains that are discarded during the formation of fibrin), which are highly non-conserved.[10]
Endogenous retroviruses
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Endogenous retroviruses (or ERVs) are remnant sequences in the genome left from ancient viral infections in an organism. The retroviruses (or virogenes) are always passed on to the next generation of that organism that received the infection. This leaves the virogene left in the genome. Because this event is rare and random, finding identical chromosomal positions of a virogene in two different species suggests common ancestry.[11] Cats (Felidae) present an notable instance of virogene sequences demonstrating common descent. The standard phylogenetic tree for Felidae have smaller cats (Felis chaus, Felis silvestris, Felis nigripes, and Felis catus) diverging from larger cats such as the subfamily Pantherinae and other carnivores. The fact that small cats have an ERV where the larger cats do not suggests that the gene was inserted into the ancestor of the small cats after the larger cats had diverged.[12] Another example of this is with humans and chimps. Humans contain numerous ERVs that comprise a considerable percentage of the genome. Sources vary, however, 1%[13] to 8%[14] has been proposed. Humans and chimps share seven different occurrences of virogenes while all primates share similar retroviruses congruent with phylogeny.[15]
Proteins
The proteomic evidence also supports the universal ancestry of life. Vital proteins, such as the ribosome, DNA polymerase, and RNA polymerase, are found in everything from the most primitive bacteria to the most complex mammals. The core part of the protein is conserved across all lineages of life, serving similar functions. Higher organisms have evolved additional protein subunits, largely affecting the regulation and protein-protein interaction of the core. Other overarching similarities between all lineages of extant organisms, such as DNA, RNA, amino acids, and the lipid bilayer, give support to the theory of common descent. Phylogenetic analyses of protein sequences from various organisms produce similar trees of relationship between all organisms.[16] The chirality of DNA, RNA, and amino acids is conserved across all known life. As there is no functional advantage to right- or left-handed molecular chirality, the simplest hypothesis is that the choice was made randomly by early organisms and passed on to all extant life through common descent. Further evidence for reconstructing ancestral lineages comes from junk DNA such as pseudogenes, "dead" genes that steadily accumulate mutations.[17]
Pseudogenes
Pseudogenes, also known as noncoding DNA, are extra DNA in a genome that do not get transcribed into RNA to synthesize proteins. Some of this noncoding DNA has known functions, but much of it has no known function and is called "Junk DNA". This is an example of a vestige since replicating these genes uses energy, making it a waste in many cases. A pseudogene can be produced when a coding gene accumulates mutations that prevent it from being transcribed, making it non-functional. But since it is not transcribed, it may disappear without affecting fitness, unless it has provided some beneficial function as non-coding DNA. Non-functional pseudogenes may be passed on to later species, thereby labeling the later species as descended from the earlier species.
Other mechanisms
There is also a large body of molecular evidence for a number of different mechanisms for large evolutionary changes, among them: genome and gene duplication, which facilitates rapid evolution by providing substantial quantities of genetic material under weak or no selective constraints; horizontal gene transfer, the process of transferring genetic material to another cell that is not an organism's offspring, allowing for species to acquire beneficial genes from each other; and recombination, capable of reassorting large numbers of different alleles and of establishing reproductive isolation. The Endosymbiotic theory explains the origin of mitochondria and plastids (e.g. chloroplasts), which are organelles of eukaryotic cells, as the incorporation of an ancient prokaryotic cell into ancient eukaryotic cell. Rather than evolving eukaryotic organelles slowly, this theory offers a mechanism for a sudden evolutionary leap by incorporating the genetic material and biochemical composition of a separate species. Evidence supporting this mechanism has been found in the protist Hatena: as a predator it engulfs a green algae cell, which subsequently behaves as an endosymbiont, nourishing Hatena, which in turn loses its feeding apparatus and behaves as an autotroph.[18][19]
Since metabolic processes do not leave fossils, research into the evolution of the basic cellular processes is done largely by comparison of existing organisms. Many lineages diverged when new metabolic processes appeared, and it is theoretically possible to determine when certain metabolic processes appeared by comparing the traits of the descendants of a common ancestor or by detecting their physical manifestations. As an example, the appearance of oxygen in the earth's atmosphere is linked to the evolution of photosynthesis.
Proteins
The proteomic evidence also supports the universal ancestry of life. Vital proteins, such as the ribosome, DNA polymerase, and RNA polymerase, are found in everything from the most primitive bacteria to the most complex mammals. The core part of the protein is conserved across all lineages of life, serving similar functions. Higher organisms have evolved additional protein subunits, largely affecting the regulation and protein-protein interaction of the core. Other overarching similarities between all lineages of extant organisms, such as DNA, RNA, amino acids, and the lipid bilayer, give support to the theory of common descent. Phylogenetic analyses of protein sequences from various organisms produce similar trees of relationship between all organisms.[16] The chirality of DNA, RNA, and amino acids is conserved across all known life. As there is no functional advantage to right- or left-handed molecular chirality, the simplest hypothesis is that the choice was made randomly by early organisms and passed on to all extant life through common descent. Further evidence for reconstructing ancestral lineages comes from junk DNA such as pseudogenes, "dead" genes that steadily accumulate mutations.[17]
Pseudogenes
Pseudogenes, also known as noncoding DNA, are extra DNA in a genome that do not get transcribed into RNA to synthesize proteins. Some of this noncoding DNA has known functions, but much of it has no known function and is called "Junk DNA". This is an example of a vestige since replicating these genes uses energy, making it a waste in many cases. A pseudogene can be produced when a coding gene accumulates mutations that prevent it from being transcribed, making it non-functional. But since it is not transcribed, it may disappear without affecting fitness, unless it has provided some beneficial function as non-coding DNA. Non-functional pseudogenes may be passed on to later species, thereby labeling the later species as descended from the earlier species.
Other mechanisms
There is also a large body of molecular evidence for a number of different mechanisms for large evolutionary changes, among them: genome and gene duplication, which facilitates rapid evolution by providing substantial quantities of genetic material under weak or no selective constraints; horizontal gene transfer, the process of transferring genetic material to another cell that is not an organism's offspring, allowing for species to acquire beneficial genes from each other; and recombination, capable of reassorting large numbers of different alleles and of establishing reproductive isolation. The Endosymbiotic theory explains the origin of mitochondria and plastids (e.g. chloroplasts), which are organelles of eukaryotic cells, as the incorporation of an ancient prokaryotic cell into ancient eukaryotic cell. Rather than evolving eukaryotic organelles slowly, this theory offers a mechanism for a sudden evolutionary leap by incorporating the genetic material and biochemical composition of a separate species. Evidence supporting this mechanism has been found in the protist Hatena: as a predator it engulfs a green algae cell, which subsequently behaves as an endosymbiont, nourishing Hatena, which in turn loses its feeding apparatus and behaves as an autotroph.[18][19]
Since metabolic processes do not leave fossils, research into the evolution of the basic cellular processes is done largely by comparison of existing organisms. Many lineages diverged when new metabolic processes appeared, and it is theoretically possible to determine when certain metabolic processes appeared by comparing the traits of the descendants of a common ancestor or by detecting their physical manifestations. As an example, the appearance of oxygen in the earth's atmosphere is linked to the evolution of photosynthesis.
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Specific examples
Chromosome 2 in humans
Main article: Chromosome 2 (human)
Further information: Genes of the Chromosome 2 fusion site in chimpanzees
Fusion of ancestral chromosomes left distinctive remnants of telomeres, and a vestigial centromere
Evidence for the evolution of Homo sapiens from a common ancestor with chimpanzees is found in the number of chromosomes in humans as compared to all other members of Hominidae. All hominidae have 24 pairs of chromosomes, except humans, who have only 23 pairs. Human chromosome 2 is a result of an end-to-end fusion of two ancestral chromosomes.[20][21]
The evidence for this includes:
Cytochrome c and b
Main article: Cytochrome c
A classic example of biochemical evidence for evolution is the variance of the ubiquitous (i.e. all living organisms have it, because it performs very basic life functions) protein Cytochrome c in living cells. The variance of cytochrome c of different organisms is measured in the number of differing amino acids, each differing amino acid being a result of a base pair substitution, a mutation. If each differing amino acid is assumed the result of one base pair substitution, it can be calculated how long ago the two species diverged by multiplying the number of base pair substitutions by the estimated time it takes for a substituted base pair of the cytochrome c gene to be successfully passed on. For example, if the average time it takes for a base pair of the cytochrome c gene to mutate is N years, the number of amino acids making up the cytochrome c protein in monkeys differ by one from that of humans, this leads to the conclusion that the two species diverged N years ago.
The primary structure of cytochrome c consists of a chain of about 100 amino acids. Many higher order organisms possess a chain of 104 amino acids.[26]
The cytochrome c molecule has been extensively studied for the glimpse it gives into evolutionary biology. Both chicken and turkeys have identical sequence homology (amino acid for amino acid), as do pigs, cows and sheep. Both humans and chimpanzees share the identical molecule, while rhesus monkeys share all but one of the amino acids:[27] the 66th amino acid is isoleucine in the former and threonine in the latter.[26]
What makes these homologous similarities particularly suggestive of common ancestry in the case of cytochrome c, in addition to the fact that the phylogenies derived from them match other phylogenies very well, is the high degree of functional redundancy of the cytochrome c molecule. The different existing configurations of amino acids do not significantly affect the functionality of the protein, which indicates that the base pair substitutions are not part of a directed design, but the result of random mutations that aren't subject to selection.[28]
In addition, Cytochrome b is commonly used as a region of mitochondrial DNA to determine phylogenetic relationships between organisms due to its sequence variability. It is considered most useful in determining relationships within families and genera. Comparative studies involving cytochrome b have resulted in new classification schemes and have been used to assign newly described species to a genus, as well as deepen the understanding of evolutionary relationships.[29]
Recent African origin of modern humans
Main article: Recent single-origin hypothesis
See also: Human mitochondrial DNA haplogroup and Human Y-chromosome DNA haplogroup
Mathematical models of evolution, pioneered by the likes of Sewall Wright, Ronald Fisher and J. B. S. Haldane and extended via diffusion theory by Motoo Kimura, allow predictions about the genetic structure of evolving populations. Direct examination of the genetic structure of modern populations via DNA sequencing has allowed verification of many of these predictions. For example, the Out of Africa theory of human origins, which states that modern humans developed in Africa and a small sub-population migrated out (undergoing a population bottleneck), implies that modern populations should show the signatures of this migration pattern. Specifically, post-bottleneck populations (Europeans and Asians) should show lower overall genetic diversity and a more uniform distribution of allele frequencies compared to the African population. Both of these predictions are borne out by actual data from a number of studies.[30]
Chromosome 2 in humans
Main article: Chromosome 2 (human)
Further information: Genes of the Chromosome 2 fusion site in chimpanzees
Fusion of ancestral chromosomes left distinctive remnants of telomeres, and a vestigial centromere
Evidence for the evolution of Homo sapiens from a common ancestor with chimpanzees is found in the number of chromosomes in humans as compared to all other members of Hominidae. All hominidae have 24 pairs of chromosomes, except humans, who have only 23 pairs. Human chromosome 2 is a result of an end-to-end fusion of two ancestral chromosomes.[20][21]
The evidence for this includes:
- The correspondence of chromosome 2 to two ape chromosomes. The closest human relative, the common chimpanzee, has near-identical DNA sequences to human chromosome 2, but they are found in two separate chromosomes. The same is true of the more distant gorilla and orangutan.[22][23]
- The presence of a vestigial centromere. Normally a chromosome has just one centromere, but in chromosome 2 there are remnants of a second centromere.[24]
- The presence of vestigial telomeres. These are normally found only at the ends of a chromosome, but in chromosome 2 there are additional telomere sequences in the middle.[25]
Cytochrome c and b
Main article: Cytochrome c
A classic example of biochemical evidence for evolution is the variance of the ubiquitous (i.e. all living organisms have it, because it performs very basic life functions) protein Cytochrome c in living cells. The variance of cytochrome c of different organisms is measured in the number of differing amino acids, each differing amino acid being a result of a base pair substitution, a mutation. If each differing amino acid is assumed the result of one base pair substitution, it can be calculated how long ago the two species diverged by multiplying the number of base pair substitutions by the estimated time it takes for a substituted base pair of the cytochrome c gene to be successfully passed on. For example, if the average time it takes for a base pair of the cytochrome c gene to mutate is N years, the number of amino acids making up the cytochrome c protein in monkeys differ by one from that of humans, this leads to the conclusion that the two species diverged N years ago.
The primary structure of cytochrome c consists of a chain of about 100 amino acids. Many higher order organisms possess a chain of 104 amino acids.[26]
The cytochrome c molecule has been extensively studied for the glimpse it gives into evolutionary biology. Both chicken and turkeys have identical sequence homology (amino acid for amino acid), as do pigs, cows and sheep. Both humans and chimpanzees share the identical molecule, while rhesus monkeys share all but one of the amino acids:[27] the 66th amino acid is isoleucine in the former and threonine in the latter.[26]
What makes these homologous similarities particularly suggestive of common ancestry in the case of cytochrome c, in addition to the fact that the phylogenies derived from them match other phylogenies very well, is the high degree of functional redundancy of the cytochrome c molecule. The different existing configurations of amino acids do not significantly affect the functionality of the protein, which indicates that the base pair substitutions are not part of a directed design, but the result of random mutations that aren't subject to selection.[28]
In addition, Cytochrome b is commonly used as a region of mitochondrial DNA to determine phylogenetic relationships between organisms due to its sequence variability. It is considered most useful in determining relationships within families and genera. Comparative studies involving cytochrome b have resulted in new classification schemes and have been used to assign newly described species to a genus, as well as deepen the understanding of evolutionary relationships.[29]
Recent African origin of modern humans
Main article: Recent single-origin hypothesis
See also: Human mitochondrial DNA haplogroup and Human Y-chromosome DNA haplogroup
Mathematical models of evolution, pioneered by the likes of Sewall Wright, Ronald Fisher and J. B. S. Haldane and extended via diffusion theory by Motoo Kimura, allow predictions about the genetic structure of evolving populations. Direct examination of the genetic structure of modern populations via DNA sequencing has allowed verification of many of these predictions. For example, the Out of Africa theory of human origins, which states that modern humans developed in Africa and a small sub-population migrated out (undergoing a population bottleneck), implies that modern populations should show the signatures of this migration pattern. Specifically, post-bottleneck populations (Europeans and Asians) should show lower overall genetic diversity and a more uniform distribution of allele frequencies compared to the African population. Both of these predictions are borne out by actual data from a number of studies.[30]
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Evidence from comparative anatomy
Comparative study of the anatomy of groups of animals or plants reveals that certain structural features are basically similar. For example, the basic structure of all flowers consists of sepals, petals, stigma, style and ovary; yet the size, colour, number of parts and specific structure are different for each individual species. The neural anatomy of fossilized remains may also be compared using advanced imaging techniques.[31]
Atavisms
Main article: Atavism
Hindlegs of a humpback whale reported in 1921 by the American Museum
An atavism is an evolutionary throwback, such as traits reappearing that had disappeared generations ago.[32] Atavisms occur because genes for previously existing phenotypical features are often preserved in DNA, even though the genes are not expressed in some or most of the organisms possessing them.[33] Some examples of this are hind-legged snakes[34] or whales[35] (In July 1919 a humpback whale was caught by a ship operating out of Vancouver that had legs 4 ft 2 in (1.27 m) long.[36]); the extra toes of ungulates that do not even reach the ground,[37] chicken's teeth,[38] reemergence of sexual reproduction in Hieracium pilosella and Crotoniidae;[39] and humans with tails,[32] extra nipples,[34] and large canine teeth.[34]
Evolutionary developmental biology and embryonic development
Main article: Evolutionary developmental biology
See also: Embryogenesis
Evolutionary developmental biology is the biological field that compares the developmental process of different organisms to determine ancestral relationships between species. A large variety of organism’s genomes contain a small fraction of genes that control the organisms development. Hox genes are an example of these types of nearly universal genes in organisms pointing to an origin of common ancestry. Embryological evidence comes from the development of organisms at the embryological level with the comparison of different organisms embryos similarity. Remains of ancestral traits often appear and disappear in different stages of the embryological development process. Examples include such as hair growth and loss (lanugo) during human development;[40] development and degeneration of a yolk sac; terrestrial frogs and salamanders passing through the larval stage within the egg—with features of typically aquatic larvae—but hatch ready for life on land;[41] and the appearance of gill-like structures (pharyngeal arch) in vertebrate embryo development. Note that in fish, the arches continue to develop as branchial arches while in humans, for example, they give rise to a variety of structures within the head and neck.
Homologous structures and divergent (adaptive) evolution
If widely separated groups of organisms are originated from a common ancestry, they are expected to have certain basic features in common. The degree of resemblance between two organisms should indicate how closely related they are in evolution:
Nested hierarchies and classification
Taxonomy is based on the fact that all organisms are related to each other in nested hierarchies based on shared characteristics. Most existing species can be organized rather easily in a nested hierarchical classification. This is evident from the Linnaean classification scheme. Based on shared derived characters, closely related organisms can be placed in one group (such as a genus), several genera can be grouped together into one family, several families can be grouped together into an order, etc.[42] The existence of these nested hierarchies was recognized by many biologists before Darwin, but he showed that his theory of evolution with its branching pattern of common descent could explain them.[42][43] Darwin described how common descent could provide a logical basis for classification:[44]
“ All the foregoing rules and aids and difficulties in classification are explained, if I do not greatly deceive myself, on the view that the natural system is founded on descent with modification; that the characters which naturalists consider as showing true affinity between any two or more species, are those which have been inherited from a common parent, and, in so far, all true classification is genealogical; that community of descent is the hidden bond which naturalists have been unconsciously seeking, ... ”
—Charles Darwin, On the Origin of Species, page 577
Comparative study of the anatomy of groups of animals or plants reveals that certain structural features are basically similar. For example, the basic structure of all flowers consists of sepals, petals, stigma, style and ovary; yet the size, colour, number of parts and specific structure are different for each individual species. The neural anatomy of fossilized remains may also be compared using advanced imaging techniques.[31]
Atavisms
Main article: Atavism
Hindlegs of a humpback whale reported in 1921 by the American Museum
An atavism is an evolutionary throwback, such as traits reappearing that had disappeared generations ago.[32] Atavisms occur because genes for previously existing phenotypical features are often preserved in DNA, even though the genes are not expressed in some or most of the organisms possessing them.[33] Some examples of this are hind-legged snakes[34] or whales[35] (In July 1919 a humpback whale was caught by a ship operating out of Vancouver that had legs 4 ft 2 in (1.27 m) long.[36]); the extra toes of ungulates that do not even reach the ground,[37] chicken's teeth,[38] reemergence of sexual reproduction in Hieracium pilosella and Crotoniidae;[39] and humans with tails,[32] extra nipples,[34] and large canine teeth.[34]
Evolutionary developmental biology and embryonic development
Main article: Evolutionary developmental biology
See also: Embryogenesis
Evolutionary developmental biology is the biological field that compares the developmental process of different organisms to determine ancestral relationships between species. A large variety of organism’s genomes contain a small fraction of genes that control the organisms development. Hox genes are an example of these types of nearly universal genes in organisms pointing to an origin of common ancestry. Embryological evidence comes from the development of organisms at the embryological level with the comparison of different organisms embryos similarity. Remains of ancestral traits often appear and disappear in different stages of the embryological development process. Examples include such as hair growth and loss (lanugo) during human development;[40] development and degeneration of a yolk sac; terrestrial frogs and salamanders passing through the larval stage within the egg—with features of typically aquatic larvae—but hatch ready for life on land;[41] and the appearance of gill-like structures (pharyngeal arch) in vertebrate embryo development. Note that in fish, the arches continue to develop as branchial arches while in humans, for example, they give rise to a variety of structures within the head and neck.
Homologous structures and divergent (adaptive) evolution
If widely separated groups of organisms are originated from a common ancestry, they are expected to have certain basic features in common. The degree of resemblance between two organisms should indicate how closely related they are in evolution:
- Groups with little in common are assumed to have diverged from a common ancestor much earlier in geological history than groups with a lot in common;
- In deciding how closely related two animals are, a comparative anatomist looks for structures that are fundamentally similar, even though they may serve different functions in the adult. Such structures are described as homologous and suggest a common origin.
- In cases where the similar structures serve different functions in adults, it may be necessary to trace their origin and embryonic development. A similar developmental origin suggests they are the same structure, and thus likely derived from a common ancestor.
Nested hierarchies and classification
Taxonomy is based on the fact that all organisms are related to each other in nested hierarchies based on shared characteristics. Most existing species can be organized rather easily in a nested hierarchical classification. This is evident from the Linnaean classification scheme. Based on shared derived characters, closely related organisms can be placed in one group (such as a genus), several genera can be grouped together into one family, several families can be grouped together into an order, etc.[42] The existence of these nested hierarchies was recognized by many biologists before Darwin, but he showed that his theory of evolution with its branching pattern of common descent could explain them.[42][43] Darwin described how common descent could provide a logical basis for classification:[44]
“ All the foregoing rules and aids and difficulties in classification are explained, if I do not greatly deceive myself, on the view that the natural system is founded on descent with modification; that the characters which naturalists consider as showing true affinity between any two or more species, are those which have been inherited from a common parent, and, in so far, all true classification is genealogical; that community of descent is the hidden bond which naturalists have been unconsciously seeking, ... ”
—Charles Darwin, On the Origin of Species, page 577
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Evolutionary trees
An evolutionary tree (of Amniota, for example, the last common ancestor of mammals and reptiles, and all its descendants) illustrates the initial conditions causing evolutionary patterns of similarity (e.g., all Amniotes produce an egg that possesses the amnios) and the patterns of divergence amongst lineages (e.g., mammals and reptiles branching from the common ancestry in Amniota). Evolutionary trees provide conceptual models of evolving systems once thought limited in the domain of making predictions out of the theory.[45] However, the method of phylogenetic bracketing is used to infer predictions with far greater probability than raw speculation. For example, paleontologists use this technique to make predictions about nonpreservable traits in fossil organisms, such as feathered dinosaurs, and molecular biologists use the technique to posit predictions about RNA metabolism and protein functions.[46][47] Thus evolutionary trees are evolutionary hypotheses that refer to specific facts, such as the characteristics of organisms (e.g., scales, feathers, fur), providing evidence for the patterns of descent, and a causal explanation for modification (i.e., natural selection or neutral drift) in any given lineage (e.g., Amniota). Evolutionary biologists test evolutionary theory using phylogenetic systematic methods that measure how much the hypothesis (a particular branching pattern in an evolutionary tree) increases the likelihood of the evidence (the distribution of characters among lineages).[48][49][50] The severity of tests for a theory increases if the predictions "are the least probable of being observed if the causal event did not occur."[51] "Testability is a measure of how much the hypothesis increases the likelihood of the evidence."[52]
Vestigial structures
Main article: Vestigiality
See also: Human vestigiality
A strong and direct evidence for common descent comes from vestigial structures.[53] Rudimentary body parts, those that are smaller and simpler in structure than corresponding parts in the ancestral species, are called vestigial organs. They are usually degenerated or underdeveloped. The existence of vestigial organs can be explained in terms of changes in the environment or modes of life of the species. Those organs are typically functional in the ancestral species but are now either nonfunctional or re-purposed. Examples are the pelvic girdles of whales, haltere (hind wings) of flies and mosquitos, wings of flightless birds such as ostriches, and the leaves of some xerophytes (e.g. cactus) and parasitic plants (e.g. dodder). However, vestigial structures may have their original function replaced with another. For example, the halteres in dipterists help balance the insect while in flight and the wings of ostriches are used in mating rituals.
Specific examples
Figure 5a: Skeleton of a Baleen whale with the hind limb and pelvic bone structure circled in red. This bone structure stays internal during the entire life of the species.
Figure 5b: Adaptation of insect mouthparts: a, antennae; c, compound eye; lb, labrium; lr, labrum; md, mandibles; mx, maxillae.
(A) Primitive state — biting and chewing: e.g. grasshopper. Strong mandibles and maxillae for manipulating food.
(B) Ticking and biting: e.g. honey bee. Labium long to lap up nectar; mandibles chew pollen and mould wax.
(C) Sucking: e.g. butterfly. Labrum reduced; mandibles lost; maxillae long forming sucking tube.
(D) Piercing and sucking, e.g.. female mosquito. Labrum and maxillae form tube; mandibles form piercing stylets; labrum grooved to hold other parts.
Figure 5c: Illustration of the Eoraptor lunensis pelvis of the saurischian order and the Lesothosaurus diagnosticus pelvis of the ornithischian order in the Dinosauria superorder. The parts of the pelvis show modification over time. The cladogram is shown to illustrate the distance of divergence between the two species.
Figure 5d: The principle of homology illustrated by the adaptive radiation of the forelimb of mammals. All conform to the basic pentadactyl pattern but are modified for different usages. The third metacarpal is shaded throughout; the shoulder is crossed-hatched.
Figure 5e: The path of the recurrent laryngeal nerve in giraffes. The laryngeal nerve is compensated for by subsequent tinkering from natural selection.
Hind structures in whales
Whales possess internally reduced hind parts such as the pelvis and hind legs (Fig. 5a).[54][55] Occasionally, the genes that code for longer extremities cause a modern whale to develop legs. On October 28, 2006, a four-finned bottlenose dolphin was caught and studied due to its extra set of hind limbs.[56] These legged Cetacea display an example of an atavism predicted from their common ancestry.
An evolutionary tree (of Amniota, for example, the last common ancestor of mammals and reptiles, and all its descendants) illustrates the initial conditions causing evolutionary patterns of similarity (e.g., all Amniotes produce an egg that possesses the amnios) and the patterns of divergence amongst lineages (e.g., mammals and reptiles branching from the common ancestry in Amniota). Evolutionary trees provide conceptual models of evolving systems once thought limited in the domain of making predictions out of the theory.[45] However, the method of phylogenetic bracketing is used to infer predictions with far greater probability than raw speculation. For example, paleontologists use this technique to make predictions about nonpreservable traits in fossil organisms, such as feathered dinosaurs, and molecular biologists use the technique to posit predictions about RNA metabolism and protein functions.[46][47] Thus evolutionary trees are evolutionary hypotheses that refer to specific facts, such as the characteristics of organisms (e.g., scales, feathers, fur), providing evidence for the patterns of descent, and a causal explanation for modification (i.e., natural selection or neutral drift) in any given lineage (e.g., Amniota). Evolutionary biologists test evolutionary theory using phylogenetic systematic methods that measure how much the hypothesis (a particular branching pattern in an evolutionary tree) increases the likelihood of the evidence (the distribution of characters among lineages).[48][49][50] The severity of tests for a theory increases if the predictions "are the least probable of being observed if the causal event did not occur."[51] "Testability is a measure of how much the hypothesis increases the likelihood of the evidence."[52]
Vestigial structures
Main article: Vestigiality
See also: Human vestigiality
A strong and direct evidence for common descent comes from vestigial structures.[53] Rudimentary body parts, those that are smaller and simpler in structure than corresponding parts in the ancestral species, are called vestigial organs. They are usually degenerated or underdeveloped. The existence of vestigial organs can be explained in terms of changes in the environment or modes of life of the species. Those organs are typically functional in the ancestral species but are now either nonfunctional or re-purposed. Examples are the pelvic girdles of whales, haltere (hind wings) of flies and mosquitos, wings of flightless birds such as ostriches, and the leaves of some xerophytes (e.g. cactus) and parasitic plants (e.g. dodder). However, vestigial structures may have their original function replaced with another. For example, the halteres in dipterists help balance the insect while in flight and the wings of ostriches are used in mating rituals.
Specific examples
Figure 5a: Skeleton of a Baleen whale with the hind limb and pelvic bone structure circled in red. This bone structure stays internal during the entire life of the species.
Figure 5b: Adaptation of insect mouthparts: a, antennae; c, compound eye; lb, labrium; lr, labrum; md, mandibles; mx, maxillae.
(A) Primitive state — biting and chewing: e.g. grasshopper. Strong mandibles and maxillae for manipulating food.
(B) Ticking and biting: e.g. honey bee. Labium long to lap up nectar; mandibles chew pollen and mould wax.
(C) Sucking: e.g. butterfly. Labrum reduced; mandibles lost; maxillae long forming sucking tube.
(D) Piercing and sucking, e.g.. female mosquito. Labrum and maxillae form tube; mandibles form piercing stylets; labrum grooved to hold other parts.
Figure 5c: Illustration of the Eoraptor lunensis pelvis of the saurischian order and the Lesothosaurus diagnosticus pelvis of the ornithischian order in the Dinosauria superorder. The parts of the pelvis show modification over time. The cladogram is shown to illustrate the distance of divergence between the two species.
Figure 5d: The principle of homology illustrated by the adaptive radiation of the forelimb of mammals. All conform to the basic pentadactyl pattern but are modified for different usages. The third metacarpal is shaded throughout; the shoulder is crossed-hatched.
Figure 5e: The path of the recurrent laryngeal nerve in giraffes. The laryngeal nerve is compensated for by subsequent tinkering from natural selection.
Hind structures in whales
Whales possess internally reduced hind parts such as the pelvis and hind legs (Fig. 5a).[54][55] Occasionally, the genes that code for longer extremities cause a modern whale to develop legs. On October 28, 2006, a four-finned bottlenose dolphin was caught and studied due to its extra set of hind limbs.[56] These legged Cetacea display an example of an atavism predicted from their common ancestry.
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Other arthropod appendages
Insect mouthparts and antennae are considered homologues of insect legs. Parallel developments are seen in some arachnids: The anterior pair of legs may be modified as analogues of antennae, particularly in whip scorpions, which walk on six legs. These developments provide support for the theory that complex modifications often arise by duplication of components, with the duplicates modified in different directions.
Pelvic structure of dinosaurs
See also: Evolution of dinosaurs and Evolution of birds
Similar to the pentadactyl limb in mammals, the earliest dinosaurs split into two distinct orders—the saurischia and ornithischia. They are classified as one or the other in accordance with what the fossils demonstrate. Figure 5c, shows that early saurischians resembled early ornithischians. The pattern of the pelvis in all species of dinosaurs is an example of homologous structures. Each order of dinosaur has slightly differing pelvis bones providing evidence of common descent. Additionally, modern birds show a similarity to ancient saurischian pelvic structures indicating the evolution of birds from dinosaurs. This can also be seen in Figure 5c as the Aves branch off the Theropoda suborder.
Pentadactyl limb
Further information: Evolution of mammals
The pattern of limb bones called pentadactyl limb is an example of homologous structures (Fig. 5d). It is found in all classes of tetrapods (i.e. from amphibians to mammals). It can even be traced back to the fins of certain fossil fishes from which the first amphibians evolved such as tiktaalik. The limb has a single proximal bone (humerus), two distal bones (radius and ulna), a series of carpals (wrist bones), followed by five series of metacarpals (palm bones) and phalanges (digits). Throughout the tetrapods, the fundamental structures of pentadactyl limbs are the same, indicating that they originated from a common ancestor. But in the course of evolution, these fundamental structures have been modified. They have become superficially different and unrelated structures to serve different functions in adaptation to different environments and modes of life. This phenomenon is shown in the forelimbs of mammals. For example:
Insect mouthparts and antennae are considered homologues of insect legs. Parallel developments are seen in some arachnids: The anterior pair of legs may be modified as analogues of antennae, particularly in whip scorpions, which walk on six legs. These developments provide support for the theory that complex modifications often arise by duplication of components, with the duplicates modified in different directions.
Pelvic structure of dinosaurs
See also: Evolution of dinosaurs and Evolution of birds
Similar to the pentadactyl limb in mammals, the earliest dinosaurs split into two distinct orders—the saurischia and ornithischia. They are classified as one or the other in accordance with what the fossils demonstrate. Figure 5c, shows that early saurischians resembled early ornithischians. The pattern of the pelvis in all species of dinosaurs is an example of homologous structures. Each order of dinosaur has slightly differing pelvis bones providing evidence of common descent. Additionally, modern birds show a similarity to ancient saurischian pelvic structures indicating the evolution of birds from dinosaurs. This can also be seen in Figure 5c as the Aves branch off the Theropoda suborder.
Pentadactyl limb
Further information: Evolution of mammals
The pattern of limb bones called pentadactyl limb is an example of homologous structures (Fig. 5d). It is found in all classes of tetrapods (i.e. from amphibians to mammals). It can even be traced back to the fins of certain fossil fishes from which the first amphibians evolved such as tiktaalik. The limb has a single proximal bone (humerus), two distal bones (radius and ulna), a series of carpals (wrist bones), followed by five series of metacarpals (palm bones) and phalanges (digits). Throughout the tetrapods, the fundamental structures of pentadactyl limbs are the same, indicating that they originated from a common ancestor. But in the course of evolution, these fundamental structures have been modified. They have become superficially different and unrelated structures to serve different functions in adaptation to different environments and modes of life. This phenomenon is shown in the forelimbs of mammals. For example:
- In the monkey, the forelimbs are much elongated to form a grasping hand for climbing and swinging among trees.
- In the pig, the first digit is lost, and the second and fifth digits are reduced. The remaining two digits are longer and stouter than the rest and bear a hoof for supporting the body.
- In the horse, the forelimbs are adapted for support and running by great elongation of the third digit bearing a hoof.
- The mole has a pair of short, spade-like forelimbs for burrowing.
- The anteater uses its enlarged third digit for tearing down ant hills and termite nests.
- In the whale, the forelimbs become flippers for steering and maintaining equilibrium during swimming.
- In the bat, the forelimbs have turned into wings for flying by great elongation of four digits, while the hook-like first digit remains free for hanging from trees.
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Recurrent laryngeal nerve in giraffes
The recurrent laryngeal nerve is a fourth branch of the vagus nerve, which is a cranial nerve. In mammals, its path is unusually long. As a part of the vagus nerve, it comes from the brain, passes through the neck down to heart, rounds the dorsal aorta and returns up to the larynx, again through the neck. (Fig. 5e)
This path is suboptimal even for humans, but for giraffes it becomes even more suboptimal. Due to the lengths of their necks, the recurrent laryngeal nerve may be up to 4m long (13 ft), despite its optimal route being a distance of just several inches.
The indirect route of this nerve is the result of evolution of mammals from fish, which had no neck and had a relatively short nerve that innervated one gill slit and passed near the gill arch. Since then, the gill it innervated has become the larynx and the gill arch has become the dorsal aorta in mammals.[57][58]
Route of the vas deferens
Route of the vas deferens from the testis to the penis.
Similar to the laryngeal nerve in giraffes, the vas deferens is part of the male anatomy of many vertebrates; it transports sperm from the epididymis in anticipation of ejaculation. In humans, the vas deferens routes up from the testicle, looping over the ureter, and back down to the urethra and penis. It has been suggested that this is due to the descent of the testicles during the course of human evolution—likely associated with temperature. As the testicles descended, the vas deferens lengthened to accommodate the accidental "hook" over the ureter.[58][59]
The recurrent laryngeal nerve is a fourth branch of the vagus nerve, which is a cranial nerve. In mammals, its path is unusually long. As a part of the vagus nerve, it comes from the brain, passes through the neck down to heart, rounds the dorsal aorta and returns up to the larynx, again through the neck. (Fig. 5e)
This path is suboptimal even for humans, but for giraffes it becomes even more suboptimal. Due to the lengths of their necks, the recurrent laryngeal nerve may be up to 4m long (13 ft), despite its optimal route being a distance of just several inches.
The indirect route of this nerve is the result of evolution of mammals from fish, which had no neck and had a relatively short nerve that innervated one gill slit and passed near the gill arch. Since then, the gill it innervated has become the larynx and the gill arch has become the dorsal aorta in mammals.[57][58]
Route of the vas deferens
Route of the vas deferens from the testis to the penis.
Similar to the laryngeal nerve in giraffes, the vas deferens is part of the male anatomy of many vertebrates; it transports sperm from the epididymis in anticipation of ejaculation. In humans, the vas deferens routes up from the testicle, looping over the ureter, and back down to the urethra and penis. It has been suggested that this is due to the descent of the testicles during the course of human evolution—likely associated with temperature. As the testicles descended, the vas deferens lengthened to accommodate the accidental "hook" over the ureter.[58][59]