Overlapping selection pressures: evolution booster?

[Gottservant]

Hi there,

Say you have selection pressures that overlap, like for example, you learn to climb trees, tall and short, both of which have fruit. Unlike you, another creature learns to climb short trees only. Theoretically you will thrive, if it turns out that short trees have limited fruit, but its not technically your adaptation that is doing it, just luck. (Say this is evidenced by the fact that every so often your tribe has a child that can only climb short trees.)

What exactly is progress in this instance? Divergence from tall tree climbing ability? When that would mean taking a chance on different terrain, say plains? Or refining tall tree climbing ability? So that you almost don't need to climb short trees at all?

Can you play chance regardless of the fact that you have learned something adaptive already? Isn't the very fact that an adaptation is there going to bias results?

Thoughts?

 

[Architeuthus]

I think you have learning and evolution confused.

 

[Gottservant]

Sorry...

uh... are you expecting me to explain something, you are saying I don't understand?

 

[AV1611VET]

Say you have selection pressures that overlap, like for example, you learn to climb trees, tall and short, both of which have fruit. Unlike you, another creature learns to climb short trees only.

Short trees = Ewoks

Tall trees = Kamonians

 

[Kylie]

There can be multiple selection pressures in effect at one time. In fact, I would say that there are nearly ALWAYS multiple pressures.

 

[AV1611VET]

There can be multiple selection pressures in effect at one time. In fact, I would say that there are nearly ALWAYS multiple pressures.

Correct.

Butter Pecan or Mint Chocolate Chip
Pepperoni & Hamburger or Pepperoni & Sausage
Filet-o-Fish or Double Cheeseburger
Kirk or Pecard

Not to mention the most famous of all time: Coca-Cola or Pepsi.

 

[Architeuthus]

There can be multiple selection pressures in effect at one time. In fact, I would say that there are nearly ALWAYS multiple pressures.

I would think so. Some relating to food (or for plants, nutrients, water, and sunlight), and some relating purely to reproduction.

 

[Kylie]

I would think so. Some relating to food (or for plants, nutrients, water, and sunlight), and some relating purely to reproduction.

ALL selection pressures relate to reproduction.

 

[Architeuthus]

ALL selection pressures relate to reproduction.

Ultimately, yes, but some relate directly to the reproductive process (e.g. seed dispersal in plants, mate selection in animals), while some relate to survival until such time as reproduction can occur.

The two can be in conflict: features which support mate selection (e.g. colourful feathers, long tail) may be negative for survival (by making a bird easier for a predator to see, or hindering movement). The net selection pressure will be a combination of the various effects.

 

[Kylie]

Ultimately, yes, but some relate directly to the reproductive process (e.g. seed dispersal in plants, mate selection in animals), while some relate to survival until such time as reproduction can occur.

But it does all relate to reproduction in that something that doesn't influence the organism's ability to reproduce isn't going to be affected by natural selection.

The two can be in conflict: features which support mate selection (e.g. colourful feathers, long tail) may be negative for survival (by making a bird easier for a predator to see, or hindering movement). The net selection pressure will be a combination of the various effects.

But it does increase the bird's chances of reproducing. And natural selection views an animal that lives for a year and produces 10 offspring to be more successful than an animal that lives for 10 years and produces 1 offspring. In short, it doesn't matter how long the individual lives for, as long as it produces lots of offspring compared to other individuals of that species.

 

[Architeuthus]

But it does all relate to reproduction in that something that doesn't influence the organism's ability to reproduce isn't going to be affected by natural selection.

Well, obviously. But you miss my point completely. Selection for purely reproductive features may be completely orthogonal to selection for survival/growth. In mate selection they intersect, but often they involve completely different attributes of the plant or animal (e.g. there may be selection on an animal to run faster and to bear larger litters). Which is what the OP was about, I think.

But it does increase the bird's chances of reproducing. And natural selection views an animal that lives for a year and produces 10 offspring to be more successful than an animal that lives for 10 years and produces 1 offspring. In short, it doesn't matter how long the individual lives for, as long as it produces lots of offspring compared to other individuals of that species.

Thank you, Captain Obvious.

 

[Kylie]

Thank you, Captain Obvious.

No need to get snarky...

 

[Architeuthus]

No need to get snarky...

Sorry.

But you were teaching your grandfather to suck eggs.

 

[Kylie]

If you apologize and then try to justify what you were apologizing for, it just tells me that your apology was not sincere.

In any case, what you said suggested that natural selection works on many different areas of fitness, whereas I was explaining that only one area matters when it comes to natural selection - how much of an reproductive advantage or disadvantage the variation gives the organism.