Atlantic cod are reaching maturity at smaller and smaller sizes. This is Illustr

Question

Atlantic cod are reaching maturity at smaller and smaller sizes. This is Illustrative of what concept? Select one: a. Species with massively reduced population sizes are undergoing genetic decline b. The adaptive landscape mapping size onto fitness has been changed by humans, and populations are evolving via selection If a new adaptive mutation escapes drift while rare, it will rapidly increase in frequency. This is sometimes associated with a 'selective sweeps that eliminates linked variation. The increasing frequency In the new mutation is favored by selection: is the sweep also favored by selection, or is it just a side effect? Select one: a. The reduction in linked variation is adaptive. b. The reduction in linked variation Is just a side-effect of selection on the adaptive allele.

Explanation / Answer

Hi,

. 1. The answer is Option B.

The cod fishes are one of the important fishes of coastal waters of the North Atlantic Ocean. These fishes are regularly caught by humans. Usually mature and larger fishes are caught due to their economic value and ease of catching. This has increased the selection pressure, wherein smaller fishes survive and they mature early. Thus with continuous fishing selection pressure entire population becomes smaller in size and early maturing.

2. The genetic sweep involves selection of a rare allele, which confirms beneficiary fitness to the organism. As the allele gets selected the genetic background i.e the neighboring genes, also get selected along with the rare allele, this is called as genetic hichchiking. The sweeps are adaptive in nature.

Hence answer is option A.

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