On 29-11-2017 4:08, omniverse wrote:
> Stephen <mca### [at] aolcom> wrote:
>> Evolution in progress. Another entry for the Darwin Awards. ;)
>>
>> Talking about Darwin (and his finches).
>>
>> http://www.bbc.co.uk/news/science-environment-42103058
> 
> Don't get me started on evolution. I've wondered a lot why there aren't more
> inbetween animals, instead of only things like the occasional Platypus
> creatures. Such as, since there are air-breathing sea-going animals like seals,
> where's the ones that only swim sometimes and mostly stay on land? Certainly not
> the polar bears, I wouldn't think. But instead there's simply one kind and then
> another entirely different kind.

Darwin's finches are exactly the examples you are looking for, and 
particularly that news item Stephen posted. Otherwise, "intermediate" 
animals are present in the fossil record but rarely to be found. Browse 
the scientific literature and you will see that the record abounds in 
all kind of intermediates.

> 
> Or in other words, the way evolution seems to be mostly finished. You don't see
> a creature becoming future whales or dolphins anymore. What happened to their
> land-based counterparts? How could they only be 100% water-borne since they
> began taking to the ocean, why not half and half, like seals and walruses?
> Somehow I doubt those are each others distant relatives, being more like
> separate animals entirely.

Not true (see the finches) and look at our own species for instance: we 
were on our way to speciation (black, white, yellow) when we thought it 
more smart to travel extensively and visit our cousins. This slowed down 
(obvious) evolution but did not stop it. Only, you do not see it happen 
in your life time. But compare skulls and skeletons from different ages 
and specialists will tell you the differences.

And don't forget our own little job of evolutionary tinkering: dogs, 
cats... what do you think those are? They are the product of controlled 
evolution, only not nature but man is the agent.

> 
> It's just that there are huge gaps from one thing to another. Maybe that's the
> way it is, some freaky biological dead zones. I just can't believe that doesn't
> mean all sorts of other creatures shouldn't also exist today. I've never really
> been convinced of a string of lineages over time from one thing to the next
> either. It's like the infamous human missing link idea, I guess only because of
> sudden change?

It is a matter of extinction and extinction rates. When you adapt to a 
particular (new) situation, there is no reason to keep the old ways so 
those traits are rapidly lost. Evolution goes very fast in most cases on 
a geological time scale, even in a matter of a few dozen generations as 
survival is often involved, and that is why most in-between changes are 
lost forever and not preserved.

> 
> I don't know, like I said, I get to thinking on that subject and it doesn't end!
> 

Keep on thinking!

-- 
Thomas

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