facts of evolution

[t8yman]

Are there creatures without eyes? I guess there are.

In which case, unless they evolved away eyes they had in the past (is anything known to have done this? I've no idea), these split from the evolutionary path that we share with the creature that evolved the original eye before the evolution of that eye.

[eFestivals]

surely thats the case for every living thing and its constituent parts?

all mammals have a womb, is that the same womb?

we all have ears - the same ear?

etc

etc

am I missing something?

I'd guess it's the case for lots of things but not all things.

For example (am using a hypothetical example because I don't know enough to give an accurate happening), it might be the case that that eye evolved before any creatures had limbs. Shortly after the eye came about the evolutionary path might have split, and these new mutations came to evolve limbs independently of each other without a common limb coming from the same creature that gave us the common eye.

(I'm struggling here for the right way of describing things cos I know so little on the subject, but hopefully that's clear enough to get it across).

[krisskross]

Yes, we all ultimately evolved from the same organism, but we have not all followed the same evolutionary path.

Some similar things have evolved independently of each other. Eyes have not.

[t8yman]

Did you see Stephen Fry on Jonathon Woss? he is doing a series about endangered species, and said that when New Zealand was formed, there were no mammals - only birds and insects - purely by chance when the continents shifted, and that some of the birds un-evolved their ability to fly due to no need to evade predators. the explorers brought rats and dogs with them and changed the entire eco system. really interesting, and something I had never heard before.

[eFestivals]

could it not be that each eye evolved independantly? I understand the cow is closer genetically to the whale than it is to the horse, so why should it be that the human eye and the sheep eye branched away from one common eye?

why? Who knows. But apparently they know via genetics/dna that there is only one eye that ever evolved, and all creatures with eyes share the creature that evolved it as a direct ancestor.

In the same programme, they said that the whale's closest modern genetic cousin is the hippo who somewhere up the chain share a common ancestor (I can't remember if they said the ancestor had a blow hole like a whale and hippo; it might be that that common ancestor had the possibility of evolving a blow hole).

[krisskross]

Coincidentally, I am currently "reading" Hitchens' "God Is Not Great" audiobook, and two days ago he was discussing this very subject, the evolution of the eye. surely the eye is just a processor of light information (forgive me, I am not a scientist) with lens etc. The eye of a bat may well be based upon the same design of eye as the hawk, yet both eyes have evolved independantly to become completely different in terms of performance, therefore they wont really be the same eye?

he also mentioned a fish that has 4 eyes, both sets of which are different in form and position, one pair on the side of the head, and one pair looking below.

It is a truly fascinating subject, but one that still swamps my tiny brain a little.

[eFestivals]

It depends on how you want to describe an eye. What most would consider an eye, have all come from the same lineage but there is another line which evolved independantly - molloscs etc. Developed from a different photoreceptor apparently.

the professor presenting the programme said that there was only one eye.

..... goes off to bbc to find out name of programme......

[krisskross]

Did you see Stephen Fry on Jonathon Woss? he is doing a series about endangered species, and said that when New Zealand was formed, there were no mammals - only birds and insects - purely by chance when the continents shifted, and that some of the birds un-evolved their ability to fly due to no need to evade predators. the explorers brought rats and dogs with them and changed the entire eco system. really interesting, and something I had never heard before.

[eFestivals]

the programme was called "What Darwin Didn't Know".

I only caught about the last half hour which was fascinating. Presumably the first hour was just as good.

From the BBC blurb....

Documentary which tells the story of evolution theory since Darwin postulated it in 1859 in 'On the Origin of Species'.

The theory of evolution by natural selection is now scientific orthodoxy, but when it was unveiled it caused a storm of controversy, from fellow scientists as well as religious people. They criticised it for being short on evidence and long on assertion and Darwin, being the honest scientist that he was, agreed with them. He knew that his theory was riddled with 'difficulties', but he entrusted future generations to complete his work and prove the essential truth of his vision, which is what scientists have been doing for the past 150 years.

Evolutionary biologist Professor Armand Marie Leroi charts the scientific endeavour that brought about the triumphant renaissance of Darwin's theory. He argues that, with the new science of evolutionary developmental biology (evo devo), it may be possible to take that theory to a new level - to do more than explain what has evolved in the past, and start to predict what might evolve in the future.

Broadcast on:

BBC Four, 9:00pm Monday 26th January

Duration:

90 minutes

Available until:

4:09am Wednesday 4th February

Category:

* Sign Zone

Credits:

Key talent

Armand Leroi

[krisskross]

link: http://www.bbc.co.uk/iplayer/episode/b00h6...win_Didnt_Know/

edit: will have a watch later - off to interview and stop being lazy and unemployed

Edited January 30, 2009 by krisskross

[t8yman]

divx available to rapidshare users if you know where to look!

[Atlanteanlost]

The professor on the programme was arguing that the eye only needed to evolve once because as an adaption it has been part of the genetic makup of every species that lives in a world where light is part of the environment. There are many species in the dark places which have never evolved eyes because they were not a relevant adaption. Also, there are those species who no longer have eyes because, even though their ancestors were sighted, they populated envronments that are dark (salamandars in caves etc).

[sifi]

I thought eyes were different in flies and birds, for example. Or the way that they process vision anyhow?

Nice idea mind.

[eFestivals]

he actually went further than that with his speculation (tho not just specifically in relation to the eye), to say that he thought the evolution of certain characteristics is pre-programmed into our DNA, thus making them coming about an inevitability. This is why he thinks it will be possible to predict future evolutionary paths.

However, he did couch that with something more, via a comparison to weather forecasting. We might fail to predict what the weather will do next month because chaos theory interferes too much to be able to get it always right, but the bigger picture of climate that unpredictable weather operates within is free of that chaos (or rather, the chaos evens out as a predictable pattern) and so predictable.

[Atlanteanlost]

I thought eyes were different in flies and birds, for example.

[eFestivals]

I thought eyes were different in flies and birds, for example. Or the way that they process vision anyhow?

any differences such as that are what have evolved since that original eye care about - they're caused by mutations to that original eye.

[Atlanteanlost]

This is why he thinks it will be possible to predict future evolutionary paths.

[sifi]

If I look around me on a Saturday morning in the High Street, I can pretty much predict where evolution is heading. Although a more appropriate word would be devolution bcause it seems to me that those primitive recessive genes are on the rise.

[eFestivals]

If I look around me on a Saturday morning in the High Street, I can pretty much predict where evolution is heading. Although a more appropriate word would be devolution bcause it seems to me that those primitive recessive genes are on the rise.

being a little less grumpy than you () and a little more optimistic, I see things such as that as a part of a two-steps-forward-one-step-back scenario.

There's plenty of times within human history that we've started to take ourselves down a certain path, to later discover our error and correct ourselves and move forwards ... only to then go thru the same routine again.

[eFestivals]

I read somewhere that in two hundred years time, there will be two distinct variations of humans. One will be very tall, thin and pale, the other will be smaller and troll like.

I can't remember which paper it was I read that in, but they did produce a picture like this under the article to underline their point.

I can predict how that will come about. Here's one of the things that'll help bring about evolution like that.....

http://news.bbc.co.uk/1/hi/uk/7854680.stm

[oafc0000]

I can predict how that will come about. Here's one of the things that'll help bring about evolution like that.....

http://news.bbc.co.uk/1/hi/uk/7854680.stm

Edited January 30, 2009 by oafc0000

[Radar]

Sooo...

If we are all evolved from a single species... why is bestiality wrong?

(Said the trolling Welshman)

[Atlanteanlost]

Sooo...

If we are all evolved from a single species... why is bestiality wrong?

(Said the trolling Welshman)

[sifi]

If we are all evolved from a single species... why is bestiality wrong?

[Radar]

So you f**k your relations?