What is directional selection?

  1. a low-frequency phenotype is selected: yes
  2. a predator could be the cause: yes
  3. the frequency of a recessive allele increases: yes

I don’t know why 1 and 3 are right.
Can anyone explain me about directional selection? :smiling_face_with_tear:

directional selection is when environmental pressure favors one phenotype more than the other
both 1 and 3 are correct. 1st one is possible in directional selection.

as you can see, one phenotype is selected over the other. for both 1st and 3rd, it doesn’t mean that the phenotype should be dominant in order for it to withstand environmental changes. it can be a low-frequency, recessive one as well. it just means that one phenotype got selected over a lot than the other one causing a big shift in the graph
hope this clears it up

Oh, it could be both low and high frequency phenotype, but since the question said one of them, that means it’s the correct answer, right? And the same goes for 3 (both recessive and dominant).
Thank you so much for your kind explanation.:grin::grin:

yes! tricky question but explains the topic very well

1 Like