Evolution Question

[dentalknight]

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Kaplan #38

Which type of selection is most likely to lead to speciatioin?

1. Directional Selection
2. Disruptive Selection
3. Sexual Selection
4. Stabilizing Selection

a) 1 and 2
b) 2 only
c) 2 and 3
d) 4 only
e) 3 and 4

I know disruptive definately dose so that cancels out d and e. i wasnt sure if the other ones cause speciation.

 

[PooyaH]

I'm thinking B! Directional would just cause an extinction of a group.

 

[doc3232]

Going with B
Directional means all the individuals change in the same manner. Is that speciation (not a rhetorical question, I am asking)?

 

[dentalknight]

well speciation is the evolution of a new species.. i know for sure disruptive selection causes that. i wasnt sure about directional and sexual, although iw as pretty sure sexual does not lead to evolution of a NEW species..

 

[PooyaH]

Going with B
Directional means all the individuals change in the same manner. Is that speciation (not a rhetorical question, I am asking)?

hmm not quite...Directional selection changes the characteristics of a population by favoring individuals that vary in one direction from the mean of the population...not all individuals change!

 

[appleonius]

i vote for A.

directional b/c one trait constantly gets selected for until the point where those individuals w/that trait can no longer breed with the original population. maybe i'm thinking too into the Q.

edit: ehh..maybe not. graph on wiki just shows a strong preference for one allele.

edit 2: maybe i was right the first time. look under adaptive radiation

 

[doc3232]

Sexual is big males and smaller females...as you said, that isn't speciation.

 

[td4azklz]

I agree A makes sense

 

[doc3232]

I agree A makes sense

So lets say, elephants weighed 20k pounds (average of all elephants), 20 years later they weigh 25k pounds (average).
Would you say those elephants are a new species?

 

[appleonius]

So lets say, elephants weighed 20k pounds (average of all elephants), 20 years later they weigh 25k pounds (average).
Would you say those elephants are a new species?

as long as they can't interbreed, then yes. 😉

 

[td4azklz]

as long as they can't interbreed, then yes. 😉

that's right, "interbreed" is the key word 😀

 

[excusezmoi]

Directional selection is it kinda relates to sympatric speciation?
Disruptive could be allopatric speciation/adaptive radiation?
so A?

but in cliffs sexual selection looks like the disruptive's graph but it's not related since it's more like a behavior...

the speciation word seem so vague...🙁

 

[AdaAda87]

Answer is definately B. Directional does not cause speciation.

 

[Optimism Smiles]

that's right, "interbreed" is the key word 😀

Only under the Biological Species Concept...😀 For the others, not so much!