Tuesday, October 31, 2006

More thinky stuff: Evolution

I don't want to get into a huge discussion, as my brains mainly thinking about cannibalism (obviously I'm not actually thinking about that lots, I just mean thats my current hypothetical discussion topic).

Here comes the question: How did bats evolve? Hannah was given a leaflet thing with that very question. Bats are mammals so evolved from another mammal. Most people ("evolutionists") think it was something like the shrew.

For us to believe in evolution (which I mostly do) we then have to accept that:

  • There was some creature between a bat and a shrew (or similar) that existed long enough to give enough offspring to be the father of all bats (possible, 1 mutation could produce offspring in an isolated place where they multiplied)
  • The in-between creature (randomly) mutated longer and lighter fingers (I can see how this could mutate a bit, but not enough for a bat to emerge without creating a really unfit creature, the fingers would not be strong enough to dig, not light enough to fly). Update: Tom's commented again saying a gradual process would work, like with gliding squirrels. The problem I have with bats though is that when a ground-dwelling, digging animal starts mutating wings, the hands will be less fit at digging and not suitable fit to start gliding. I don't think it could be a mutation over millions of years. Maybe nuclear radiation or something mutated a few creatures lots and they got lucky.
  • There are no intermediate fossils between species around today (acceptable, I haven't done sufficient digging myself). Update: Tom's commented again! He says the creationist argument of the eye not being able to evolve (e.g. 1/2 an eye wont work) is poop. I think it's poop too. Tom also says not having fossils isn't really a problem. I'm not so sure. As there's lots of fossils, by chance there should be fossils of inter-special creatures. I don't think there are any. If there were then everyone would know about it. Let me know if I'm wrong.
It definitely seems possible. Personally I find it much easier to believe that God took a shrew and converted it into a bat. I bet he even said "Hazzar!". What do you think? (Tom, I expect another prize-winning comment :-)

Update: Mike's said "evolution is a fact (probably)". Facts and theories aren't opposite things, they're different categories. Evolution is a theory based on facts (and I guess some assumptions too). Becky says "appreciate them for really cute furry flying machines". I do. Becky also seems to like simplicity (maybe that was a bit rude. Sorry :-).


Tommeh said...

Don't have time right now for a comment of legendary proportions, but I expect they developed possibly like how some species of squirrels developed gliding ability with an extra bit of skin between limbs and themselves. Then perhaps they evolved to strengthen this and eventually more control over them and began to propel themselves a bit, and the ones that were better obviously survived and then bats were like "Yo, screw the squirrels, we're batty". etc.

Tommeh said...

Also I don't think the lack of fossil evidence so far for some of the Bat record should be worrying for evolution. As things like the age old creationist arguments like the eye not being able to be evolved cos its too complicated etc are often based on ignoring a lot of facts. Though in this case its true there is over 50% of the fossil record not got yet, there's still a lot there, and they can see they branched off about 50 million years ago or something I think I read somewhere. Anyway I gotta stop typing cos I could go on about evolution all day and that wouldn't help with me writing 500 words by Friday about something I have researched yet. ARGH.

Michael said...

Wibble? All I know is that it is all over my head... evolution is a fact. Simple. Probably.

becky said...

dave, why the sudden intense philosophical/religious debates? bats exist. full stop. they have done for a long time, and we're never going to know exactly at what point they became bats as opposed to anything else. just appreciate them for really cute furry flying machines and the world will seem a far simpler place. trust me.

Tommeh said...

Btw latest South Park, and in fact the next one, all about Evolution. Tis the funny

Tommeh said...

Also the prob is there's a lot more underground than overground and the amount of people actually looking for fossils is tiny, and they're always finding new fossils that fit in new places. I reckon it just takes time.

Tommeh said...

Whoa, I have insomnia and was browsing this blog of wonder against and came across this. More thoughts and research flooded in. Apparently only 60% of the fossil record for bats is missing, though obviously that's the majority, that's still 40% available, which is impressive as apparently the frail tiny bones of bats do not fossilise well, so a large reason for the lack of a fossil record is just the small chance of fossils surviving.

Other people have been working on the genes of bats, and it appears it only took 1 gene to be activated to allow the ancestors of bats to grow extended digits, which could explain how bats evolved flight so rapidly.

In conclusion I don't think a theory, such as evolution, can be thrown out simply because we have some missing evidence, it seems unlikely we'll be able to get 100% of all the evolutionary evidence ever, just because it doesn't exist anymore, and that's just how nature works. But the overwhelming majority of evidence seems to point towards evolution. Plus I don't think you can't certify one theory based solely on faults or missing details of another.

Disclaimer: I don't pretend to be knowledgeable on this subject, and my views will never probably be unbias in nature.