Question

QUESTION The rough-skinned newt, Taricha granulosa, is a common prey species for garter snakes, Thamnophis sirtalis. odotoxin biosynthes s in newts is poary understocd, but its mechanism of action is known: the toxin binds to the Voltage-0ated Na channel found on the membrane of nerve cells and bigcks actico pctentias in nerves and muscles Garter snakes that prey on newts become poisoned if they eat TTX-producing newts. However, resistance to TTX has evolved in some garter the votage-gated sodium channel (Nav) gene. One of these mutations, D1684N, prevents the toxin binding to the channel, resulting in a highly resistant, yet functional NaV channel protein ake populations. The TTX-resistant phenotype in snakes is associated with mutations in Rough-skinned newt Garter snake Which of these words or phrases best describes resistance to TTX in garter snakes? BItis a beneficial alleie. C. It is a genotype. D. It is the result of exposure to TTX. QUESTION 2 If asked how the ability to resis: tetrodotoxin evolved in a snake population that initialy dd not have this ability, a biologist would infer that such evolution mos: likely occured by A. genetic drif B. gene flow D any one of these mechanisms QUESTION 3 3 points] The mutant allele, Na which confers resistance t (assuming that garter snakes continued to eat TTX-producing newts)? Briefly explain your reasoning. TTX, is dominant to the wild-type allele, Na. Would you expect that, over tme, the recessive wild-type allele would completely eliminated from the popuiation 3 (12pt) #TEE T TT Arial Words 0 Path: p Click Save and Submit to save and submit. Click Save All Answers to save all ansuvers. Save All Answers Close

Answer 1

1. It is an adaptation

The resistance to TTX during evolutionary trade‐offs is predicted to arise in the process of local adaptation. The snakes underwent adaptive evolution in response to a selective challenge.

2.