Evolution and Natural Selection

[zkt]

Since the validity of evolution and natural selection has become a hot political topic:

Biology Online Course, Khan Academy Biology, Salman Khan | Free Video lectures, Download

 

[beav7]

Do evolutionists believe that evolution kind of reacts to what is needed for survival?
For example if a certain animal needed longer legs or whatever in order to survive better or hunt better then would this somehow magically trigger an evolutionary process so that the offspring would then suddenly have longer legs to have bigger chances of survival?
If this is the case then I wonder why has evolution not yet given us humans a third eye or maybe a pair of wings in order to fly? Wouldn't it be pretty practical to have a third eye on the back or some wings to take off and fly to the supermarket? I really wonder why evolution isn't doing anything about this.
Is it possible that evolutionary processes need some kind of trigger, maybe a mental trigger and that evolutionary processes only kick in when the animals really despair and think something like Man I really needed longer legs and this mental stimulus then serves as a trigger to cause all kinds of mutations?

 

[jmills]

Beav, seriously?
Here is a simple explanation of evolution/natural selection:
Organisms tend to go through tiny changes within their species. Some of these changes confer an advantage to them, such as a different colour skin, which helps them avoid predators. Consider a type of moth, which is preyed upon by birds in the twilight. Those who benefit from this advantage will tend to live long enough to breed, passing it on - this is the origin of the slightly confusing phrase "survival of the fittest" - confusing because 'fittest' in this case is not to do with being strongest or fastest, or biggest and best fighter, but the one 'fitting-in' to the environment.
The whole Theory of Evolution depends on these tiny changes, which are called 'mutations'. Some will not help at all, leading nowhere. These will not tend to be passed on. The mechanism of these mutations, is quite possibly simply errors in DNA replication from parent to their off-spring.

The way you talk about evolution, it seems to me like you think it is something that "happens" magically right now...but its not...its something that tends to happen by tiny changes over (mostly) many generations.

Hope that helps a little,
Jmills

 

[zkt]

Beav, why dont you just watch the videos ? Kahn is a really smart guy who wants nothing more than to spread the light of understanding.

 

[beav7]

What if you need a whole set of changes all at once? Imagine a little critter which lived a few million years ago. Now luckily through a mutation it developed a set of teeth but unfortunately it cannot swallow yet because it doesn't produce saliva. What does it do now?

 

[zkt]

You win. I give up.

 

[beav7]

You win. I give up.

You mean you have no answer for my question?

 

[jmills]

What if you need a whole set of changes all at once? Imagine a little critter which lived a few million years ago. Now luckily through a mutation it developed a set of teeth but unfortunately it cannot swallow yet because it doesn't produce saliva. What does it do now?

It dies...and doesnt pass that mutation along...and I dont think you got a response because maybe Z didnt think you would understand a response given your questions and the responses you've already recieved.

 

[beav7]

If it dies then this means you actually needed multiple mutations all at once. I wonder how likely that is. Then I wonder why don't we see babies being born with wings or third eyes? Why doesn't this "simply" happen? After all evolution is still working right?

 

[ergomaniac]

If it dies then this means you actually needed multiple mutations all at once. I wonder how likely that is. Then I wonder why don't we see babies being born with wings or third eyes? Why doesn't this "simply" happen? After all evolution is still working right?

obviously not well enough.
because beav. evolution is a long process. and most mutations dont just "simply" happen for no reason. and multiple mutations would mean a new animal in its entirety.
mutations either survive or they dont. and theres a reason. are they functional. or are they just for convenience. evolution doesnt just happen so you can fly to the grocery store. survival of the fittest is the way it works. or so it should. but the human race is different. and different gifts can sometime contribute to the whole. some athletes think not so good. some good thinkers not so athletic. and some are just artistic ( flakes). like me. really somewhere inbetween is best. i think. so you can handle all of lifes problems. bigger, faster, stronger, better. just in case. and the most applicable.
really though. little babies arent born with wings and three eyes for a reason.
they dont have fangs and claws. really beav. how can little babies be born with wings and three eyes. if they dont have fangs and claws. think for a minute. ok stop. got it. its just common sense. fangs. claws. wings. and a third eye. awww. so cute.
and you know whats next right?...

 

[Michael Scally MD]

What if you need a whole set of changes all at once? Imagine a little critter which lived a few million years ago. Now luckily through a mutation it developed a set of teeth but unfortunately it cannot swallow yet because it doesn't produce saliva. What does it do now?

How do you use this example to demonstrate evolution? What you describe is a random mutation that would work against life. This is more analogous to aberrant mutations seen in nature now that go nowhere!

 

[ergomaniac]

obviously not well enough.
because beav. evolution is a long process. and most mutations dont just "simply" happen for no reason. and multiple mutations would mean a new animal in its entirety.
mutations either survive or they dont. and theres a reason. are they functional. or are they just for convenience. evolution doesnt just happen so you can fly to the grocery store. survival of the fittest is the way it works. or so it should. but the human race is different. and different gifts can sometime contribute to the whole. some athletes think not so good. some good thinkers not so athletic. and some are just artistic ( flakes). like me. really somewhere inbetween is best. i think. so you can handle all of lifes problems. bigger, faster, stronger, better. just in case. and the most applicable.
really though. little babies arent born with wings and three eyes for a reason.
they dont have fangs and claws. really beav. how can little babies be born with wings and three eyes. if they dont have fangs and claws. think for a minute. ok stop. got it. its just common sense. fangs. claws. wings. and a third eye. awww. so cute.
and you know whats next right?...

scales and a tail.
am i the only one thinking here?

 

[beav7]

Where is the difference between random mutations and evolution?
Evolution is based on random mutations. This means that one day long ago before something like teeth existed a creature must have been born which due to a mutation suddenly had the first teeth. And then, because teeth are so practical, this creature survived and passed the teeth on to its descendents, right?

Now if something like teeth all of a sudden developed then why should other things not also be able to develop all of a sudden? Then it also wouldn't be impossible for a baby being born with a third eye or wings on its back. It could virtually happen any second in one of the millions of hospitals on the planet. This is actually a pretty scary thought.