What do you know "without googling" about the reputed mechanisms for evolution? (page 2)

inkling

It's really pretty pathetic, actually.

Well, we all wait with bated breath for you to enlighten us
from the patheticness of our error strewn ways...

[inkling] <--- offically annoyed by this wankery

TD

I read and hear people speak of the volumes of data pro or con and when I ask for specific examples of what each may be referring to, I am often met with silence.

I always hesitate to get into these discussions, because in the past, I've ended up conversing with people that truly, honestly don't know what a species is, how one is discovered, how one is described, and how that description is accepted or rejected.

Here is an example that I have some experience with. It's not earthshaking and it won't change anyone's mind, but for those with an actual hands-on interest in biology, (As opposed to arm-chair Googlers) it is tile in the larger mosaic:

A seminal work on family Cactacea in America was done by Briton and Rose in the 1920's. These two gentlemen did a lot of field work and collected a lot of specimans. The result was a four volume work entitled "The Cactacea"

Since then, this family has been reorganized every 25 to 30 years. Major recent works have concentrated on individual genera within this family. For example, John Pilbeam has recently written on mammillaria, Graham Charles has recently written on gymnocalicium and, Rudolf Schulz has recently authored a book on copiapoa.

Each time one of these books is published, two things happen: (1) A few species that were previously described can no longer be found in the wild. Some species described by Briton and Rose for example, exist only in cultivation today. (2) A few new species are discovered.

This can only happen so many times before the idea that species both come into and drift out of existence faster than was previously thought starts to sink in.

People can say, "What's the big deal? A cactus is still a cactus and plants freely hybridize in the wild anyway." I would answer, "True -- but when the result is an entirely new species, you are describing a "reputed mechanism for evolution." --Remember the mantra, "Any change to a breeding poplulation at or above the level of species.""

inkling

And if this is going to end up like "nope, the answer we were looking
for was blind chance. Thanks for playing", I swear to dog I will jump
though this monitor and throttle you.

You know, with all due respect

[inkling]

BurnTheShips

Throttle me too please. I don't know what I am talking about.

inkling

Here's a simplified illustration of genetic drift: A group of people leave their home and sail to another land. They meet with disaster at sea and only half of the people make it to the new land. By coincidence, all the survivors happen to have blue eyes. Therefore, while the proportion of blue eyes relative to other colors was only 50% of the original group, it is now 100% of the surviving group and therefore 100% of the genetic stock that will reproduce at the new land.

Ahh, ok.

So in this case, if you were to imagine a evolutionary biologst
in the future studying these people, if he had to explain everything
via natural selection, he would assume that blue eyes imparted
some survivability advantage in the past, and he would be wrong.

Sometimes shit just happens, and a gene ("good" or "bad") gets
popular by basically winning a lotto rather than "working" their
way up.

Also, if you took the same situation, except all the brown-eyed
people were specifically killed by, say, a racist, then in that case
it WOULDN'T be drift, right? Because even though it only happened
once, blue eyes did in fact increase their survivability.

[inkling]

inkling

Throttle me too please. I don't know what I am talking about.

I'm just worried you might enjoy it...

Midget-Sasquatch

Honestly gubberningbody, this pretense of you knowing how ignorant the rest of us are, and how we're not getting it is, is condescending.

You've gotten an excellent summary on the key drivers of evolution with natural and sexual selection as well as a solid description of the way chance can come into play with bottlenecks and genetic drift.

Yes the mutations themselves are to the best of our knowlegdge undirected, but the selective pressure on the phenotypes that result from those altered genotypes tends to direct in someway. Now that direction may not always be towards complexity, but it sure has generated alot of diversity.

Let's have something more relevant to the discussion instead of insults.

Satanus

Just taking a peek in the door. Carry on, gentlemen.

S, ooohing and aahhhing ;))

inkling

Let's have something more relevant to the discussion instead of insults.

Here here!

Thanks Midget-Sasquatch.

What with the whole Mother Teresa nonsensical "joke"
thread, and now this, I am starting to think GB is being
intentionally obtuse. Someone needs attention maybe? Oh well, at least it has given the rest of us a change to
have an actual, you know, "conversation" involving the
exchange of information and ideas.

[inkling]

villabolo

Survival of the most reproductive in a given environment.This is as concise as it gets. For an example take wingless birds. The mutation that gives an occasional bird a stunted wing would assure their death before being able to reproduce by virtue of the fact that they could not fly away from predators. However if these birds were to migrate and take up residence in a secluded island where there are no natural predators any mutation like that would not kill them in fact it would improve their chances for survival during drought induced famines due to the fact that wings are metabolically expensive to maintain if there is no good reason to maintain them.

A famine that may kill, let's say, 50% of all birds on the island may just leave the wingless bird scrawny and weak. As soon as the famine ends the population of normal winged birds doubles along with the wingless one except that now the wingless one is overrepresented-his numbers has doubled in proportion to the "normal" birds. As these cycles of famine continue, every few centuries or so, the wingless birds eventually out repoduce the winged ones and a new species is born.

What do you know "without googling" about the reputed mechanisms for evolution?

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