The California newt, Toricha toroso, lives in the coastal areas around Los Angeles. Which of the following is a valid null hypothesis relating fitness to survival of a bottleneck event in a coastal area where a small, isolated population of California newts resides?

(A) Only those salamanders with the lowest evolutionary fitness will be eliminated by the bottleneck effect, lowering the allelic frequencies of their traits.
(B) Only those salamanders with the highest evolutionary fitness will survive the bottleneck event, raising the allelic frequencies of their traits.
(C) Surviving the bottleneck event will be random, so any change in the allelic frequencies of the salamander population is not attributed to fitness
(D) Surviving the bottleneck event will be random, so there will be no changes to the allelic frequencies due to the bottleneck event.

(B) Only those salamanders with the highest evolutionary fitness will survive the bottleneck event, raising the allelic frequencies of their traits.

Explanation:

Toricha toroso is a type of salamander which lives in the coastal areas of California after the bottleneck event. Bottleneck event is a kind of event in which population of organisms are reduced due to harsh climatic condition. In these harsh climatic condition of the environment, Toricha toroso survive because of the fitness of this salamander. Fitness plays a vital role in the survival of organisms.

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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.