Convergent evolution

[Moontanman]

Examples of convergent evolution are the similar shapes of Earthworms, worm snakes, Caecilians, worm lizards, glass lizards, amphiumas, real snakes, eels, sirens. The long slender legless or almost legless shape has been repeated many times. How many different examples of convergent evolution can be found?

 

BTW convergent evolution is an important example of why evolution is false according to creationists.

[Ganoderma]

although they appear different, those designs are all incredibly different and varied. for example worms have hairs which help to move. caecilians have a hard head and push out their skin/scales and use their spine and head like an arrow to push forward. snakes use belly scales to move back and forth, eels swim....

 

they are all legless (although some some snakes have leg remnants - boids-), but its like saying a dogs and elephants are the same guess we can split hairs anyway up the chain though eh?

 

one interesting example is ergoline alkaloids found in fungi (where lsd gets is origin). it is also found in some plants (convolvulaceae). it was theorized to be as said above. 2 groups, in this case in different kingdoms, managed to get the same chemicals. later on, ie now, it is found that they live in harmony together and the fungi seems to develop the chemicals and the plant accumulates them. i thought this was interesting how science is showing symbiotic relation ships in weird new ways.

 

i think one of the coolest things though would be 2 eyes.

 

the problem with evolution and creationism theories are, they can both argue their point, and there is no way to either prove or disprove either one. "god made it that way" or "nature made it that"...i gave up as it seems god and nature are one in the same...helps me think less lol.

[C1ay]

i gave up as it seems god and nature are one in the same...

 

Ahh, a pantheist among us

[Moontanman]

although they appear different, those designs are all incredibly different and varied. for example worms have hairs which help to move. caecilians have a hard head and push out their skin/scales and use their spine and head like an arrow to push forward. snakes use belly scales to move back and forth, eels swim....

 

they are all legless (although some some snakes have leg remnants - boids-), but its like saying a dogs and elephants are the same guess we can split hairs anyway up the chain though eh?

 

one interesting example is ergoline alkaloids found in fungi (where lsd gets is origin). it is also found in some plants (convolvulaceae). it was theorized to be as said above. 2 groups, in this case in different kingdoms, managed to get the same chemicals. later on, ie now, it is found that they live in harmony together and the fungi seems to develop the chemicals and the plant accumulates them. i thought this was interesting how science is showing symbiotic relation ships in weird new ways.

 

i think one of the coolest things though would be 2 eyes.

 

the problem with evolution and creationism theories are, they can both argue their point, and there is no way to either prove or disprove either one. "god made it that way" or "nature made it that"...i gave up as it seems god and nature are one in the same...helps me think less lol.

 

I think you are missing the big picture here. yes in close up detail all these animals are quite different, but Caecilians move across the surface with serpentine movements just like a snake, eels move across land the same way, as do sirens, amphiumas, even some worms do this. They all swim the same way, the ones that live under ground move in very similar ways, worm snakes and worm lizards look so much like worms, right down to the segmented rings on their bodies that are often mistaken for worms, only their dry bodies and dry habitats give them away. All these animals exploit the long worm like shape in similar ways to similar ends. Such similarities show up in four footed creatures as well, although horses, dogs and elephants are far more closely related than a snake and glass lizard much less a snake and an eel. Convergent evolution occurs all around us at the visual level. These animals have all evolved similar body plans under similar stresses and natural selection. There are other basic groups of similar body plans in animals that are far removed from each other in evolutionary terms. I was hoping for more examples but i will give another good one. Ichthyosaurs, sharks, and dolphins come to mind.

[Getting A Life]

Form depicts function. They (worm shaped organisms) move like that because they are made like that. I could walk on my hands with enough practise, but the way I am shaped, it conserves much energy to walk on my feet.

 

Form depicts function.

 

An example is the femur/metatarsal ratio in quadropeds. The higher the ratio the (potentially) faster an animal is. We can predict the speed of an extinct organism fairly accurately through examining this ratio and if the foot is plantigrade, digitigrade or centigrade. Applying the same ratio to extant species gives the expected results. Higher femur/metatarsal ratio = faster animal.

 

Whereas, if you examine the wide leg stance of reptiles leg bones compared to mammals you will almost immediately understand why they undulate their bodies side to side in a 'waddle' as they walk like they do.

 

The remnants of limbs are known as vestigial structures. Found in dolphins, whales, snakes...

[Moontanman]

No getalife, snakes do not move in a serpentine motion because they are legless. They are legless because natural selection favored that shape due to environmental pressures. the serpentine motion started before the loss of legs. It can bee seen today in some lizard species that are beginning to loose their legs because they don't need legs due to using their bodies in the serpentine motion being more efficient in their natural environment.

 

The form of the long legless body has evolved many times in many totally different animals due to natural selection. mammals seem to have missed the boat on this body from unless you count ferrets, the little snaky bastards are as close being snakes as any mammal I know of.

 

The pressures of natural selection have driven evolution to repeat many body forms over the last 500,000,000 years. You could walk on your hands and if the hand walking made you more likely to have offspring at some point, thousands if not millions of generations hence, your descendants just might walk on their hands naturally but not because you can hand walk but because natural selection favored you because you could.

[Getting A Life]

I am not saying they move that way because they are legless. I am saying they move that way because that is the most efficient way of moving without legs. Rolling would not work as too many obstacles would get in their path.

 

Form depicts function, right from a molecular level.

[Moontanman]

So are you saying there is no convergent evolution?

[freeztar]

I don't think he's saying that. In fact, it seems you are both on the same page as far as homoplasy is concerned, just coming at it from different angles.

 

Form does depict function (most of the time anyway), but that is a direct result of convergent evolution acting on species with unrelated ancestors adapting through natural selection to the same, or similar, environments.

 

Bats, birds, and pterodactyls all have wings, though they are only distantly related on a cladogram. They evolved wings separately, but for similar "reasons".

[Moontanman]

Earthworm

 

 

Worm caecilian

 

 

Worm Lizard

 

 

Worm Snake

 

 

 

Kid snake

 

[Moontanman]

I think it is also interesting that you don't see huge herbivorous snakes sliding around, most large herbivores conform to certain body shapes as well.

[Getting A Life]

I am in agreeance with what you are saying MTM except me 'not believing' in convergent evolution. The pictures are great thanks.

 

I was trying to point out that convergent evolution not only displays similar form, but the form denotes similar function - thus explaining a bit about why convergent evolution appears. Thanks to Craig, too.

 

I'm fascinated by natural 'function'. So many plans tested over geological time. With convergent evolution not only do we get to see these plans in working displays, they're also peer reviewed in other organisms. (ok, now I'm taking liberties...) :rolleyes:

 

I find it difficult not to anthropomorphize animals. Not if you've seen a bit of kanzi...

 

YouTube - Kanzi with lexigram http://www.youtube.com/watch?v=wRM7vTrIIis&feature=related

 

Pretty impressive.

[Moontanman]

Sorry Getting a life, my mistake, BTW how do you get a life? I want to know I need one :naughty:

[Getting A Life]

No problem.

 

Well, getting a life... Having been blinded by a fundamentalist background I am only recently 'enlightened'. So I have gone back to school and am learning about science.

 

Upon dropping the god paradigm I had a bit of an existential quandary - what now? Finally realised I needed to be engaged with life at some level for it to make sense. Now I'm busy learning science I've never been happier.

 

Purpose. Being purposeful. Getting a life.

 

Back to discuss evolution later, I'm off to an Alan Carr clinic see if they can't hypnotise me into not smoking... Very cynical, we shall see.

[Moontanman]

No problem.

 

Well, getting a life... Having been blinded by a fundamentalist background I am only recently 'enlightened'. So I have gone back to school and am learning about science.

 

Upon dropping the god paradigm I had a bit of an existential quandary - what now? Finally realised I needed to be engaged with life at some level for it to make sense. Now I'm busy learning science I've never been happier.

 

Purpose. Being purposeful. Getting a life.

 

Back to discuss evolution later, I'm off to an Alan Carr clinic see if they can't hypnotise me into not smoking... Very cynical, we shall see.

 

You're a brave man "getting a life" very few people are brave enough to even question their world view much less actually change it. My hats off to you for sure. I hope the hypnosis works :)

[Boerseun]

Back to the OP - why would convergent evolution be in support of the idea that evolution never happened?

 

Whales' closest living family is the hippopotamus, if memory serves. Whatever the case may be, their closest relatives are land-based mammals. Yet you would never say so on the face of it, because if truth be told, they look like fish. Fins, the works. Sleek hydrodynamic design, everything.

 

I think convergent evolution is a perfect example of animals evolving to suit their niches. Similar environmental challenges being solves with similar means. Nature might be cruel, but she's very economical. I think it supports evolution way more than the fundies might think.

[Moontanman]

Back to the OP - why would convergent evolution be in support of the idea that evolution never happened?

 

Whales' closest living family is the hippopotamus, if memory serves. Whatever the case may be, their closest relatives are land-based mammals. Yet you would never say so on the face of it, because if truth be told, they look like fish. Fins, the works. Sleek hydrodynamic design, everything.

 

I think convergent evolution is a perfect example of animals evolving to suit their niches. Similar environmental challenges being solves with similar means. Nature might be cruel, but she's very economical. I think it supports evolution way more than the fundies might think.

 

This isn't the first place I found this idea but it is expressed here the same way.

 

 

Creation versus Evolution :: Truth Watch :: Test Everything, Hold on to the Good

 

The numerous examples in biology of so-called "parallel evolution" in which completely different species have developed similar features or skills on supposedly different evolutionary paths also contradict the random-chance premise of evolution. This is more adequately explained by the creationist view of there being a common designer who has elected to use common design features in different creatures.