Talk:Convergent evolution

Bad Example

A picture of an owl and cat are compared, and it is said that they have conversantly evolved directional ears. The tufts on some owls' heads have nothing to do with hearing, they are display structures, so this doesn't constitute an example of convergent evolution. — Preceding unsigned comment added by 50.131.184.173 (talk) 18:09, 30 October 2011 (UTC)

Opening paragraph

Bats' wings and birds' wings are convergent, but are also homologous with each other and with human arms. All three evolved from the forelimbs of their common reptilian ancestor. Grassynoel (talk) 04:41, 10 September 2010 (UTC)

Convergent/Parallel evolution and subsequent animal classification

Is there a categorization of animal that groups them based in their morpohology, that is, in the total of their phenotypes? Ignoring phyllogenetic trees and all... Just based in what "looks alike"? Mmm... For example placing tazmanian devils with coyotes and dogs... Placing rhinos with triceratops and worms with snakes or cats with saber-tooth tigers? Undead Herle King 09:09, 24 June 2007 (UTC)

Sure - you just call it a paraphyletic system of classification; a bit like speaking of reptiles and excluding aves, or talking about all fish. Or maybe just in classifying all things that swim as sea creatures - including whales, fish, and seals all together. One might see this referred to as an nichetype. Aderksen (talk) 20:53, 20 October 2008 (UTC)

thanks for the data, now... I'm thinking of this for its importance to the historic and trans-ethnic meaning of animals to the humanity that has met them... The place of wildlife in human culture is based more on paraphyletic taxonomies (so paraphyletic that unlike grouping reptiles and ignoring aves it demands a wildy variant series of selections of creatures to exclude and no simple rule would predict a phylogenetic-based algorythm to determine its operation) limited by a particular ethnias historically derived knowledge than on what science has found out about the origin of species. Symbolism occurs at face value and, while the shapes animals have has a lot to do with their niche, their niche makes up just a portion of what causes their shape; anacondas, bears, crocodiles, octopus and vampire bats all prey on animals one way or another but they all are different...

To humans not influenced by science they have less in common that hares, hyraxes, pikas and guinea pigs... Even worms, eels, snakes and caecilians are more closely related to their eyes, even if worms and snakes do not share the same niche, I do not know which niche caecilians fill, but I hope my point gets across... Likewise "aquatic creatures" might serve as a category in the classifications I'm asking if anyone knows to exist, however it would have sub-categories that might cross-reference other categories, eels would for example cross-reference a category for slithering creatures, for creepy crawlies, due to their similitude with snakes. Tadpoles and fish would probably be grouped together no matter whether fishes are fresh water or salt water fishes. Walruses would belong to a nearby category with some primitive amphibians because, morphologically, they aint exactly fish-like, decapods and jellyfishws would be grouped together, and so on...Undead Herle King (talk) 11:27, 13 July 2009 (UTC)

Sentence modified

I changed "also developed similar to insects due to the need to detect smells in the air." There is no directed evolution. Evolution is thought to be a blind and purposeless process. Birds did not evolve wings because they needed to fly. Giraffes did not evolve long necks because they needed to feed on tree leaves.

The idea of "nature did this and that because of this and that" has no room in a materialistic world view. Everything is just pure chance of mutation and merciless natural selection.

And of course a materialistic worldview is the only valid one, right?

Rebuttal: This view is that of this particular author and is not accepted by everyone, a large group believe that giraffes actually did evolve long necks in order to reach the new 'type' of trees which had leaves taller. They developed and evoloved in order to reach a environmental niche which hadn't as yet been utilised. (Aswell as other reasons i'm not going to go into now). This topic is still greatly debated and i urge you to research using other materials in order to reach you opinion.

Commenting on the rebuttal: The point about evolution being directed should be clarified. Giraffes did not "evolve long necks in order to reach the new 'type' of trees which had leaves taller. They developed and evoloved in order to reach a environmental niche which hadn't as yet been utilised." This implies foresight and a goal, neither of which exist. This should be phrased as "those giraffes that happened to have longer necks were better able to survive and reproduce, and passed on the alleles for longer necks in a higher proportion compared to other alleles." However, there is compelling evidence that giraffe necks are not adaptations for feeding at all, but rather for combat. I recommend the article "Winning by a neck: Sexual selection in the evolution of giraffe" by RE Simmons and L Scheepers, published in American Naturalist Vol. 148, no. 5, pp. 771-786. Nov 1996. The gist of it is that:a) male giraffes fight for mates by clubbing each other with their heads/necks, b) during the dry season when food is scarce, giraffes still feed on lower vegetation available to other browsers, and c) the neck has increased much more than the legs, even though legs provide a much more economical way of gaining height. Even though it seems "obvious" that the long neck is for feeding on higher leaves, it is important not to make conclusions without investigation.

Well stated, anonymous poster! Always be wary of the "just so story" and the Panglossian paradigm! Aderksen (talk) 20:59, 20 October 2008 (UTC)

From immediately below "Sentence Modified" is "Evolution is thought to be a blind and purposeless process." This is incorrect. Mutation is a somewhat random process - limited by the nature of DNA which picks up fewer mutations than RNA for example - but evolution is directed by successful mutations where success is indicated by long term replication success. — Preceding unsigned comment added by Dna replication (talk • contribs) 15:54, 26 January 2012

Marsupials vs placentals

What about the marsupials of australia vs the placentals of everywhere else? Isn't this considered an example, too? There are bear-like, mouse-like, wolf-like, squirrel-like marsupials. - Omegatron 01:32, Jan 3, 2005 (UTC)

http://www.nwcreation.net/images/marsupials.gif maybe public domain?

• Added, thank you.Telecine Guy

Yes, and there are some good examples

Campbells Biology 7th edition notes these in a nice chart on page 969 (Marsupial/Eutherian): Plantigale/Deer Mouse Marsupial Mole/Mole Sugar Glider/Flying Squirrel Wombat/Woodchuck Tasmanian Devil/Wolverine Kangaroo/Patagonian Cavy —Preceding unsigned comment added by 24.95.246.192 (talk) 05:16, 9 December 2007 (UTC)

• Added, thank you.Telecine Guy

New paragraph moved for discussion

I removed the following paragraph from the article.

several anti-evolutionist critcisms have pointed out that the explanation of convergent evolution make darwinain homologies basically immune to critcism, one of many ways it is alledged evolution makes itself virtually immune to falsification, and hence "unfair". Some authors have gone as far as to claim that darwinism is compatiable with all (or basically all) possible worlds, hence making it unscientfic, or even pseudoscientfic, using the hypothesis of convergent evolution as a example of such "data avoidance", CF popper. Evolutionary biologists usually respond by saying that evolution only has so much "wiggle room" and hence if false could be proven so by certain results.

Could someone explain how convergent evolution makes evolution unfalsifiable? That doesn't make any sense to me, although I should disclaim that I am a firm believer in science and religious criticisms of science rarely make sense to me. Can the contributor provide any scientist works that allege such problems with evolution's falsifiability (since the criticism seems to be of scientific problems with evolution, and not of the "my book says it's not so" variety). — Knowledge Seeker দ (talk) 09:22, 7 Jan 2005 (UTC)

Doesn't make sense to me, either. - Omegatron 23:22, Jan 22, 2005 (UTC)

As I hold this view myself, I'll try to explain. When one is trying to support or discredit evolution, one looks at the animals alive today and judges whether they show evidence of having evolved that way or were more or less created that way. Things like amphibians support evolution, because they're seemingly a transitionary stage between fish and reptiles, but to see two creatures that look nearly identical yet are supposedly genetically very different would imply that they were created that way by a higher being that enjoyed that shape. Because evolution is said to be random, i.e. mutations happen completely at random and hopefully only beneficial ones make it into the gene pool, it would be an amazing coincidence for the same set of mutations to occur -twice-, just like lightning striking twice. (for that matter, a lot of scientists believe it's an amazingly rare phenomenon for any mutation to be beneficial) For a creationist, this seems like a good argument, then evolutionists come out with 'convergent evolution' without any explanation as to -why- it occurs, but simply a claim that it does, as a defense.. and to us it seems an unfair defense, as it's completely unfalsifiable. When evolution follows expected rules, it makes sense, yet when it doesn't, they seem to make up new rules to -make- it make sense. Understand?

I don't believe that organisms that have some similar property but that are genetically different (why the supposedly?) implies that they were created that way. There is more than one way to accomplish a certain task, like construct an eye, for instance. Evolution is decidedly not random: mutations may be, but the ones that survive, and therefore the progression of the gene pool, is highly directed—that's why evolution works. You are correct that it would be unlikely for the same set of mutations to occur twice—but organisms displaying convergent evolution have similar features from entirely different genes. I don't believe convergent evolution is a new concept that scientists have recently come up with, but I will try to explain why it occurs. Fins arose in the early vertebrates (the fish) presumably because they help the animals to move faster and more efficiently, and therefore are more likely to survive. However, they're not too useful on land, although legs are, which is why land animals have these. But the group of mammals that spent increasing amounts of time in the water had an advantage if they could swim more efficiently, and this was likely the reason for the progression of forelimbs to flippers and the regression of the hind limbs in the dolphins and whales (and the muscular tail). There are only so many ways to propel oneself in the water; it is not surprising that a smooth, solid (as opposed to having separate digits) appendage occurs in both sharks and dolphins, animals that very superficially resemble each other (enough so that dolphins were once considered to be fish, like sharks). Even human swimmers use a similar apparatus (flippers that are smooth, rubbery, solid, and with a large surface area) to help them move through the water, since our appendages are clearly not well-suited for aquatic travel. The similarity between dolphins and sharks is superficial, however. Dolphins are "warm-blooded" like other mammals, give birth to live young, and need to breathe air like other mammals. Most telling, however, is the anatomy of the homologous structures. The fins of a shark are constructed like the fins of other fish, and sharks too swim with their tail oriented vertically, moving from side to side. Dolphins, however, are descended from land mammals like we are. The bones of their flippers include a shortened humerus (arm bone), radius and ulna (forearm bones), carpals, metacarpals, and five "fingers", with the corresponding numbers (three phalanges for the 4 fingers, two for the "thumb"), just like in us. Why dolphins should have a distorted "hand" inside their flippers makes little sense from a design perspective, but makes perfect sense considering their origin. Incidentally, most whales/dolphins don't have hind limbs, although some have tiny vestigial ones deep inside their bodies. Also, the spine of a dolphin is like ours—it bends more easily and more powerfully forward and backwards (or for the dolphin, up and down), not side to side—so their tails are oriented horizontally and they move their tails up and down to swim. In fact, it is similar to the way a human with flippers swims—and different from the sharks and other fish. That's convergent evolution—superficially similar structures, to accomplish the same task, but arising by different routes. Convergent evolution would be expected, not a surprise. As for your point of the appearance of new rules, I'm afraid that's how science works. If new evidence arises, then you try to find a new theory that best explains the available evidence. Sometimes it means modifying the theory. Sometimes it means coming up with a whole new theory. If new information comes to light, we modify or discard the theory, instead of stubbornly clinging to it as overwhelming evidence continues to accumulate. — Knowledge Seeker দ 05:33, 18 October 2005 (UTC)

Could someone just please post a link to an article which describes how convergent evolution occurs, instead of just giving examples? I think this would mollify the folks crying "unfalsifiable". - LyleK

There aren't any, that's the problem. Nobody knows "why" or "how" it works, it's just a term made up to explain an observation.

B-U-L-L-S-H-I-T to the nth degree. Look up natural selection and ecological niche and population genetics and exaptation in any good encyclopedia anytime. This is not the 19th century anymore.

"it's just a term made up", yeah, right... Do me a favor: learn to read. You can write, so not all hope's lost...

Sop you wanna have an example? Here goes:

Shrew-like mammal lives on ground, has forelimbs, can dig a bit. Some descendants dig better than others. Some decendants are also mutations, freaks, cripples, you name it - but they can still make some sort of living. Some of these happen to have clubby hands and stumpy fingers. Makes them better diggers, if nothing else.

Repeat for say 500.000 generations.

Repeat again, this time with a sort of grasshoppery insect.

Result? Moles and mole crickets.

This could essentially be done for any case on the list - the bottom line is that in evolution, any property that doesn't kill you will get tried out. And "any" is, basically anything that natural variation is able to produce (including heritable diseases). And that is a lot.

The problem with people like you is, you have NO FRICKIN IDEA HOW MUCH it is. You have noit the slightest inkling of understanding what biodiversity is or what it means.

There is one case in the list where I am abolutely sure that I at least cannot give an answer, and I think nobody can. The look-alike longspur and meadowlark.

Assuming that Genesis is right and Darwin is wrong [which may well be so, but shutting your ears and singing "lalala no evidence can't hear you" won't get you anywhere], the closest thing to a "proof" for that would be a bunch of songbirds that are pretty irrelevant in the big scheme of things.

What does this tell you about God?

(Believe me - you'll be better off with trusting in evolution. God, if He exists, is either a bitch who finds it more important to create mosquitos and beetles than to care about humans, or a freak on LSD.) Dysmorodrepanis (talk) 04:27, 16 February 2008 (UTC)

parallel convergence

please clarify the difference between parallel and convergent evolution - Omegatron 23:22, Jan 22, 2005 (UTC)

Done. Let me know if you feel this requires further elaboration - Gdvorsky 19:54, Jan 22, 2005 (EST)

i think i get it, but it requires me to think about it a second. some examples would be great. eyes are used as examples in both articles, which probably contributes to my misunderstanding. - Omegatron 04:07, Jan 23, 2005 (UTC)

Oh! i get it, i think:

• convergent evolution: insects, octopuses, and fish-->birds/fish-->mammals all have eyes, but some branched off from the others before eyes had evolved

• parallel evolution: birds and fish both have streamlined body plans and broad flat appendages which happen to work well in both environments - Omegatron 04:11, Jan 23, 2005 (UTC)

Yes, I think your examples are close, but I would like to get some better examples in there. Currently working on it... - Gdvorsky 23:34, Jan 22, 2005 (EST)

Okay, I think that now *I* finally have it. I've clarified the definitions of both convergent evolution and parallel evolution, and added yet a third phenomenon, evolutionary relay. I also removed the discussion of mimicry, as I don't believe it's in the same family of evolutionary processes as these three -- but I did add mimicry to each article's Related articles section. - Gdvorsky 13:25, Jan 23, 2005 (EST)

Good work... but are parallel evolution and evolutionary relay specific instances of of the more general term, convergent evolution? 68.81.231.127 21:34, 24 Jan 2005 (UTC)

I believe the answer is no, for a reason that facilitated me making these changes in the first place. A post-grad friend of mine recently got nailed during an evo-bio oral examination for not correctly distinguishing between convergent and parallel evolution, prompting me to find the answer. That being said, I think all these entries are still very insufficient, not taking into account things like systematics characters, molecular-level convergence/parallelism, evolutionary regression into convergence/parallelism, etc. Unfortunately, this topic is outside my expertise. - Gdvorsky 21:48, Jan 24, 2005 (EST)

I am having trouble understanding the difference between convergent evolution and evolutionary relay. The article says that what distinguishes the latter is a separation in time, but the evolution of pterosaur wings and bat wings and bird wings (the examples given for convergant evolution) are certainly well-separated in time. And the shark/ichthyosaur example seems weird because sharks were, actually around back when ichthyosaurs evolved. So the examples given don't clarify anything for me. --Xkcd 11:35, 27 February 2007 (UTC)xkcd

New section for "examples"

I made a new section here for "other examples", hoping to encourage some other interesting and exotic examples of convergent evolution. I included some recent findings on the poison dart frog (found in a NY Times article, http://www.nytimes.com/2005/08/09/science/09frog.html). Archie Paulson 21:11, 10 August 2005 (UTC)

A Good Addition; this may lead to some new 'break-out' articles. I am pretty sure that there are macroscopic(family and order) versions(as in Australia vs the rest of the Continents) of Conv. evol. vs smaller, family and genus versions. I am adding the New World vultures and the Old World vultures. The New world use Smell, the Old world are in the Eagle family and use Sight (I found this out working on a bird page.).MMcAnnis--Mmcannis 05:31, 24 February 2006 (UTC)

"Form follows Function", i.e.--Convergent evolution

It seems too easy to forget the main reason for creating a term: Convergent Evolution. It is as simple as: Form–follows–Function. It is why virtually all of the placentals evolved species categories equivalent to the marsupials, or vice-versa. (It is obvious the oldest and earliest explorers all saw this.) ..MMcAnnis--Mmcannis 18:41, 26 February 2006 (UTC)

Brilliant! Dysmorodrepanis (talk) 04:28, 16 February 2008 (UTC)

Not sure where I should put this, but I wanted to say it :) "Similarity can also be explained by shared ancestry, as evolution can only work with what is already there - thus wings were modified from limbs, as evidenced by their bone structure." (from the [Convergent evolution] page). Doesn't this beg the question: "where did the limbs specialize from?" —Preceding unsigned comment added by 130.126.161.132 (talk) 22:42, 5 March 2009 (UTC)

unreferenced

I added the unreferenced tag to this article. Perhaps one or a few standard texts on evolutionary biology could serve. 24.196.111.46 05:39, 11 April 2006 (UTC)

Merge from Morphological convergence?

Most of the examples here seem to concern anatomy already. Melchoir 22:20, 23 April 2006 (UTC)

This seems like a good idea - morphological convergence is a subtopic of this article, and it would be difficult to explain it properly without referencing most of the content presented here. Mike Serfas 02:14, 30 April 2006 (UTC)

2 levels of "convergent evolution"

1-It should be noted that there are individual, a species level of convergent evolution.

2-However, on a Macroscopic level, all of continental australia has forms with analogues in the Placental world vs the Marsupial.

I am not sure that "Morphological convergence" or Convergent Evolution, is addressing these two major, topical distinctions, of Convergent Evolution.--MichaelMcAnnisYumaAZ,USA--Mmcannis 09:46, 20 May 2006 (UTC)

Convergent evolution does also occur at the molecular and physiological levels. While is currently is not covered, it provides justification to keep the entries separate.

Prof. J.D. Pettigrew FRS of UQ Brain Institute has written the paper "Summary of Studies on Primate Phylogeny and 'Flying Primate' Hypothesis" (http://www.uq.edu.au/nuq/jack/consensus.htm) which addresses problems in assessing phylogeny from a purely DNA-based analysis. He points out that genetic drift in certain areas can heavily distort the relevance of any comparison. There is a suggestion that environmental factors actually impose a level of genetic convergence, I think. 211.26.165.199 (talk) 08:27, 24 October 2008 (UTC) Ian Ison

Interesting find, Ian. I don't think it's a WP:RS in its own right and note that it was last updated in 1999, which is a long time in the relatively new discipline of molocular phylogenetics, but it can certainly provide plenty of leads for searching. -- Philcha (talk) 11:08, 24 October 2008 (UTC)

removed questionable bullet

• "Spines have evolved in several mammal groups independently - Echidnas (Monotremes), Hedgehogs (insectivores), Old World porcupines (Rodents) and New World porcupines (a separate group of rodents). In this case, because the two groups of Porcupines are relatively closely related, they would be considered to be an example of parallel evolution; neither Echidnas nor Hedgehogs, however, are closely related to Rodents at all. In fact the last common ancestor of all four groups was a contemporary of the Dinosaurs."

Excuse me, what? "spines have evolved in mammals"? I suppose before that key event, they were part of the little-known but widespread group of spineless mammals? Spines - to the best of my knowledge - are thought to have evolved before any animal put foot (or flipper) on land, in anchient fish, carried into tetrapods, diapids, therapods (the proto-mammals), and kept the *whole* time, right up untill placentals, marsupuals and monotremes diverged. So no convergent evolution there - Jack (talk) 02:06, 20 July 2006 (UTC)

Wrong spines. We're talking about the spiky ones. Is there a better word for those? - Samsara (talk • contribs) 08:24, 20 July 2006 (UTC)

Lol. *kicks self* should have thought bout it before I launched into rant - Jack (talk) 13:32, 20 July 2006 (UTC)

Regarding the perported contradition between parallel and convergent evolution; I believe this stems from a misunderstanding between the two concepts.

Parrallel evoluton refers to the evolution of similar traits which have resulted from similar ancestral characteristics. For example Marsupials in Australia and Placentals in south America share similar ancestors but have developed in parallel although seperated as a result of plate tectonics resulting in continental drift.

Convergent evolution species on the other hand do not have similar ancestors or traits. It is the case that evolution have arrived at the same answer to a problem through different developmental pathways. for example; a bats wing, a bees wing and a birds wing are all different in structure, in terms of homology, but represent a similar solution to the problem of flight.

cliveClive140359 12:09, 9 May 2007 (UTC)

"Not monophyletic" organisms?

I think that this criterion is somewhat unclear, since there are no special creations, all life is monophyletic at some point. More proper would be something like that "organisms that aren't from far related taxa or clades", even though it is not quite clear as well, how much relatedness is far and how much is close. Actually I don't even know and I'm often guilty of using "parallel" and "convergent" interchangeably (not on wikipedia, calm down). Not that it really is. Related with this issue, the article of evolutionary relay, a obscure, new to me, distinction of parallel evolution even cites bees and hummingbirds hovering flight as parallel evolution. If such phyletic distance is yet "monophyletic" enough, real convergence would occur only between plants and animals, terrestrials and aliens or something as far as that. --Extremophile 17:26, 9 November 2007 (UTC)

Links to this page

I noticed that Homoplasy redirects here but the term itself is never mentioned. Would somebody please add a definition? HannsEwald (talk) 00:33, 23 April 2008 (UTC)

• Done, thank you Telecine Guy 05:23, 7 October 2008 (UTC)

Improvements

This article has just been serviced by the Cambrian Explosion Task Force! Find out how you can get involved.

We're hoping to get this article up to "B-class", and your input would be welcomed. The article could use input from a sociocluturalist to at least cite the reference to cultural evolution, and comments on its structure would be welcomed. Martin (Smith609 – Talk) 02:22, 7 October 2008 (UTC)

Kapow!! (for the explosion) Possibly then from Vere Gordon Childe that describes "divergence" and "convergence". Rursus dixit. (^mbork³!) 19:54, 3 May 2010 (UTC)

Discussion

(Copied from WT:CEX)

Without looking anything up, just based on vague memories of articles I've edited recently, there's quite a lot more, with sources. I suspect Googling for "convergent evolution convergence convergently" using advanced search restricted to Wikipedia would get quite a lot. A few items that spring to mind:

• Bats' and birds' wings.
• "Rampant convergence" in spiders' webs.
• There's got to be something in Halwaxiid.
• Convergent evolution of Malphigian tubules in terrestrial members of arthropod sub-phyla, with loss of nephridia.
• Convergence of segmentation in annelids and arthropods, if the Ecdysozoa / Lophotrochzoa split is right.
• Coelom in protostomes and deuterostomes.
• Camera eyes - how many times?
• Venomous fangs in spiders, ants, snakes & beaded lizards.
• Warm-bloodedness in mammals and in birds / dinos.
• Problem-solving intelligence in spiders, octopuses, birds and mammals.
• In cladistics, "parsimony" = "minimum of convergences and reversals" (in PAUP).
• There have to be examples in our articles of convergence either confounding phylogenetic analyses and / or invoked as "get out of jail" cards. -- Philcha (talk) 17:03, 20 October 2008 (UTC)

Given my own personal research biases, I'd have to suggest that you go ahead and include insects as examples of convergence in flight - they have wings which perform the same function, but then you can conveniently demonstrate them as an obvious outgroup when compared to the descendants of tetrapods. Or maybe that would be tossing too many ideas at people at one time?

Would it also be worthwhile to point out that neutral convergence exists for things like DNA sequences, where random chance (n ~ 1:4) or chemical probability (C-->G swaps) will create similar sequences? Aderksen (talk) 20:31, 20 October 2008 (UTC)

I've tried to avoid turning the article into a list of examples of convergent evolution, because I think the focus should be on the concept. I think it's more beneficial to keep the article short and concise so the points are clear than to try and make it fully comprehensive, which may be an impossible task! Martin (Smith609 – Talk) 21:15, 20 October 2008 (UTC)

Also, does C->G count as convergent evolution? I've never hears the phrase applied in that sense before and wonder how appropriate it is. Martin (Smith609 – Talk) 21:18, 20 October 2008 (UTC)

Martin, I sympathise with your desire to avoid another "list" article. I produced these examples off the top to show the range of levels at which convergence can operate, from body plans to behaviour. Now Aderksen has reminded us both that convergence can also bedevil mol phylo, which I think is a very important point - I'm sure there must be good RNA examples to avoid your concern about whether C->G is really convergence. I'd go for one example in each of body plans, behaviour, mol phylo and warm-bloodedness (physiology) plus 1 morphological / functional example at an intermediate level.

As your comment implies, there's also a lot of theoretical significance to explain. -- Philcha (talk) 21:44, 20 October 2008 (UTC)

"Arthropods have failed to evolve a camera eye"

This statement is probably false - the main ocelli of jumping spiders are very acute and have a "telephoto" lens system, see spider for more info and refs. --Philcha (talk) 11:42, 20 November 2008 (UTC)

It basically depends on how restrictive you are in the definition of "camera eye" (ie, just like humans and octopi, or including all other single-lens systems). It is rather suspect, though, as a result. I did a bit of poking around on google scholar, and could find very little on "camera eye" + spider, or even just "camera eye" - it seems to be a vernacular term, rather that a precise scientific one, hence the problem of sloppy definition. Mokele (talk) 13:49, 20 November 2008 (UTC)

Mokele's point about sloppy definition is a good one. Pax 6: mastering eye morphogenesis and eye evolution does not actually define "camera eye" but says cephalopods and vertebrates have them, and also the bivalves Cardium and Pecten (scallop), with a nice diagram of all the eye types the authors consider. The difference between Cardium+Pecten and vertebrates+coleids (i.e. cephalopods excluding Nautilus) appears to be that in vertebrates+coleids the lens is adjustable, but that's just my WP:OR and I found no sources that said this. I can find sources that use "camera eye" to describe those of vertebrates and of coleid cephalopods, and "pinhole eye" or "pinhole camera eye" to describe that of Nautilus (e.g. Ruppert, E.E., Fox, R.S., and Barnes, R.D. (2004). Invertebrate Zoology (7 ed.). Brooks / Cole. p. 361. ISBN 0030259827. ). Looks like possession of a lens is the key feature. I still think "Arthropods have failed to evolve a camera eye" is very questionable and probably plain false, and should be removed unless supported very strongly by WP:RS. --Philcha (talk) 14:54, 20 November 2008 (UTC)

I've done a little looking and it seems that to me the biggest difference between human eyes and compound eyes is single lense + pupil + sensor (ie camera lense, shutter, film) where compound eyes have multiple lenses/sensors and no pupils - but I'm no biologist. The best (first? or only?) site I could find that made reference to a camera eye was http://library.thinkquest.org/28030/eyeevo.htm#camera and this site uses somewhat different functional definitions of "simple eye" and "compound eye" from those in eye. Also the three sentences beginning with "However, evolutionary history can act as a constraint..." don't sit well with me personally, but more importantly they don't contribute anything relevant to the topic of the article.---Puff (talk) 03:42, 29 December 2008 (UTC)

This is by no means the accepted view as a google search for "advantages of the compound eye" will reveal:

this reference shows that the reasons for the existence of the two systems exist are not that well understood, and to quote from here

There is, however, a great advantage to the compound eye system. Image processing is so much more efficient than is the case with, for example, a human's eyes, that the compound eye offers a much greater flicker fusion rate. This means that an insect can assimilate changes in what it's seeing many times more quickly than we can.

Also in Next-generation cameras inspired by fruit flies and moths it says:

insects such as fruit flies and moths have a completely different type of eye called compound eyes to accommodate the animals’ small size and low brain processing capabilities…The arrangement allows for a large field of view, but does not require large signal processing

I have expanded the example and added new references but it may be that it just isn't a good example and should be removed. Richerman (talk) 12:00, 16 March 2009 (UTC)

Wrong examples?

1. It is not clear, why marsupials and mammals are an example of convergent evolution. To me it seems divergent evolution.

2. The development from photoreceptive spot to eye may be bare evolution or parallel evolution, but development of human eyes beside compound eyes is divergent evolution (from the same ancestrial genes).--Wickey-nl (talk) 16:43, 4 June 2009 (UTC)

Marsupials vs mammals refers to specific instances where two are very similar, such as the mole and marsupial mole. As for eyes, it's specifically talking about the 'camera eye', which, in two separate lineages developed more or less the same form independently. Mokele (talk) 18:26, 4 June 2009 (UTC)

Not really an answere.
1. What is the acquired common trait in both lineages? This is an exemple of parallel evolution (see Parallel_evolution#Parallel_evolution_between_marsupials_and_placentals) so it should be deleted here.
2. When talking about the 'camera eye' we have a bare evolution (from photoreceptive spot to simple and compound eyes). When talking about simple eyes versus compound eyes we have a divergent evolution in the case that one of the two was developed first. We have a parallel evolution in the case that both developed independant in both lineages from the photoreceptive spot. In all cases it does not belong in this article. --Wickey-nl (talk) 07:10, 5 June 2009 (UTC)

There seems to be some confusion here, To quote from the Parallel evolution article:

When the ancestral forms are unspecified or unknown, or the range of traits considered is not clearly specified, the distinction between parallel and convergent evolution becomes more subjective. For instance, the striking example of similar placental and marsupial forms is described by Richard Dawkins in The Blind Watchmaker as a case of convergent evolution, because mammals on each continent had a long evolutionary history prior to the extinction of the dinosaurs under which to accumulate relevant differences. Stephen Jay Gould describes many of the same examples as parallel evolution starting from the common ancestor of all marsupials and placentals.

Now you're saying its divergent evolution - do you have a reference for that? Richerman (talk) 12:55, 5 June 2009 (UTC)

Indeed, it's crucial to specify of which trait(s) you are speaking. That is neglected here.
When the ancestor splits into two lineages, marsupials and placentals, there is developement into different directions. So clearly divergent evolution.
When, starting from the photoreceptive spot, one lineage develops 'simple' eyes and one lineage compound eyes there is also clearly divergent evolution. Logical arguing. There is no acquisition of the same biological trait in unrelated lineages.--Wickey-nl (talk) 14:48, 7 June 2009 (UTC)

The problem is that the distinction between convergent and parallel is subjective at best. "Unrelated lineages" is wrong - there are NO unrelated organisms, all life descends from a common ancestor. So the issue then becomes "how far apart, morphologically or phylogenetically, do organisms have to be for it to be 'convegent' instead of parallel? I remember having this debate recently at a discussion group with some faculty, and nobody could pin down a difference (and this is at an Ivy League school).Mokele (talk) 16:15, 5 June 2009 (UTC)

With 'unrelated lineages' here is meant: two lineages that developed independant starting from a common ancestor. --Wickey-nl (talk) 14:48, 7 June 2009 (UTC)

I know, but it's a sloppy term, and should *NEVER* be used. I actually think there's no difference between convergent and parallel evolution, and it's all just a consequence of people being sloppy with terms. If two organisms develop the same trait independently, and the common ancestor lacked that trait, it's convergent evolution. Parallel evolution is the same thing with a different name, usually applied to more closely related organisms. Mokele (talk) 16:58, 7 June 2009 (UTC)

I don't agree. Convergence means that two different traits develop to one alternative trait. That's the opposite of divergence and not the same as parallel.--Wickey-nl (talk) 17:13, 7 June 2009 (UTC)

That's easy to say, hard to actually apply, especially for morphology. What is "one trait" that's converged upon, and how precisely? Wings could be seen as convergences, but that's a very *broad* description of the structures, and each wing is different at the finer scale. And how do you define "two diffferent traits", especially when you're dealing with something as broad as overall body plan? Consider snakes and amphisbaenians: both evolved from lizards, and both lost their limbs. If this parallel, because the start and end points are the same, or convergent, because snakes went through an aquatic phase while amphisbaenians didn't? Does the process matter, or is it just the start and end points? Mokele (talk) 19:44, 7 June 2009 (UTC)

Yellow legs and red legs are two different traits which can converge to orange (or brown) legs.
Lizards is a good exemple. If snakes and amphisbaenians lost their limbs independant (after some generations) it would be a parallel evolution (with snakes and amphisbaenians with limbs between). If there was an ancestor between lizard on the one hand and snakes and amphisbaenians on the other hand and that ancestor already lost his limbs, then there was a bare evolution between lizard and the ancester between. No convergence because there was no developement from different traits (or better different species with different traits) to different species with the same trait. The problem could be the determination wether there was such an ancestor between or not. For that you need genetic data. --Wickey-nl (talk) 10:35, 8 June 2009 (UTC)

Do not replace the content of this page with your oversimplified, pedestrian understanding of this concept. I have tried to educate you on the complexities of this issue, and you've merely showcased your ignorance. Any further edits without explicit talk-page consensus will be considered vandalism. Mokele (talk) 21:15, 8 June 2009 (UTC)

The only thing that a real simple mind can do is reverting an edit.--Wickey-nl (talk) 11:48, 9 June 2009 (UTC)

Are owls ears really targeted? In what sense do you mean? I think many people will think that you mean both cats and owls can rotate their ears when an owl just has ear tufts and it's actual ears are very different. — Preceding unsigned comment added by 68.80.183.113 (talk) 23:16, 26 September 2011 (UTC)

Convergent evolution in humans

A good example—“the best example of convergent evolution in humans that I’ve ever seen,” according to Joel Hirschhorn, a geneticist and paediatrician at Children’s Hospital Boston, Massachusetts—can be found in NATURE, Vol 444, 21-28 December 2006 in the article: "How Africa learned to love the cow" by Erika Check. It describes the discovery of convergent evolution in humans with regard to lactose tolerance by adults. (Africans apparently evolved it completely separately—and quite recently—from Europeans.) RobertM525 (talk) 04:06, 26 January 2010 (UTC)

Adaptations towards malaria#Evolutionary pressure of malaria on human genes would be another example. Some may consider them parallel evolution anyway. In the malaria example, some may even consider it divergent evolution. Of course these would be better in the list Nil Einne (talk) 11:15, 5 February 2010 (UTC)

Intelligence

I came across these refs http://www.genomeweb.com/sequencing/phylogenomic-study-points-convergent-evolution-humans-and-elephants http://www.pnas.org/content/106/49/20824.abstract regarding evidence for covergent evolution among humans and elephants for intelligence. I thought of inserting them under the part that mentions intelligence but it only meantions crows, primates and dolphins so doesn't really fit. But perhaps they'll be useful somewhere Nil Einne (talk) 11:34, 5 February 2010 (UTC)

Distinction from re-evolution

This paragraph describes genes as having a lifespan dictated in years, surely the lifespan is dictated by generations instead? With 'years' being the product of generations x lifespan? 188.141.100.24 (talk) 13:14, 18 July 2010 (UTC)

Further Reading

The link given in

- Convergent Evolution Examples- Ecological Equivalents, Department of Biology, Bellarmine University.

is currently broken. I have left it, since it may be fixable and/or someone may know where the content has been moved. If not, it needs to be removed or replaced. 87.113.177.37 (talk) 01:41, 25 August 2011 (UTC)

Homoplasty

"Homoplasty" redirects here, but the page only mentions "Homoplasy", which I believe is something different. "Homoplasty" is "the formation of homologous tissues" per Webster 1913. 86.182.222.189 (talk) 13:24, 30 November 2011 (UTC)

Owl/Cat example not referenced and questionable

The owl/cat example has several problems. (1) The example doesn't have a reference. (2)Both could be images of domestication not evolution. (3)The taxa is not given for either. I think the removal of that part is vital especially since the doll face silver persian image represent human intervention in these character states and thus not evolution by natural selection. So this isn't convergent evolution. BenjaminDHolland

It's called "selective breeding". Obviously not convergent evolution. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:44, 4 January 2012 (UTC)

It's always [[Natural selection] unless you are saying that being a Human is not natural. Selective breeding is a form of selection typically associated with pressures from one particular Species. Dna replication (talk) 19:03, 27 January 2012 (UTC)

Dollos law is not holding up to scrutiny

As DNA sequencing converges with cladistic analysis it is becoming clear that Dollos law does not hold water [1]. Someone should edit the second sentence of the section "Distinction from re-evolution" to reflect this current knowledge... which does cause one to ask how this could become a law while evolution remains classified as a theory - ergo what constitutes a proof. — Preceding unsigned comment added by Dna replication (talk • contribs) 15:54, 26 January 2012

Dna replication, if you are knowledgeable in the subject, be bold and add it yourself! Welcome to Wikipedia! jonkerz ♠talk 19:08, 27 January 2012 (UTC)