If a variety of light colored moths and dark colored moths lived in a forest of trees with a lighter colored bark and the environment changed causing the bark to darken, what will likely happen to the frequency of the genes that control the light and dark colors? A.
The frequency of the dark colored gene increases and the frequency of the light colored gene decreases.
B.
The frequency of the light colored gene increases and the frequency of the dark colored gene decreases.
C.
The gene frequency of the light and dark genes remain the same.
D.
The frequency of the dark colored gene stays the same and the frequency of the light colored gene increases.

A.

Explanation:

Dark coloured moths will be better camouflaged and so better protected from predators. More of them will survive and reproduce, increasing the frequency of dark coloured genes.

Light coloured gene will provide less camouflage, those moths will be caught by predators more often and live to reproduce less. So the light coloured gene will decrease.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.