What is true about the isolated small tribal populations?

The correct option is C

there is a decline in population as boys marry girls only from their own tribe

The correct option is C.

Explanation of the correct option:

1. Since the guys would marry the girls from their own tribe, there would be no gene flow or gene migration, and as a result, the population would decrease.
2. A phenomenon like inbreeding depression is to blame for the population drop. Here, homozygosity is elevated, which lowers an individual's capacity for reproduction and lowers the population.
3. The term "inbreeding depression" refers to a similar phenomenon seen in livestock. This happens when inbreeding persists or when it is closed, which lowers fertility or productivity.

Explanation of the incorrect option:

Option A:

1. Characteristics that are acquired during one's lifetime and are not passed down from one's parents are known as acquired characteristics, while those that are passed down from one's parents to one's offspring are known as inherited characteristics.
2. Wrestlers develop strong muscles; they do so through exercise and diet, not through their genes.
3. Since genes are irrelevant in this situation, these traits are not passed down to the kids.
4. It serves as an illustration of acquired character.

Option B:

1. Due to a deficiency in either the red or green cones of the eye, a person with colour blindness is unable to distinguish between red and green colours and perceives an intermediate colour as grey.
2. It is a sex-linked recessive condition caused by mutations in specific X chromosome genes.
3. Because the gene pool of small isolated communities will be small, inbreeding in those populations will lead to the spread of genetic illnesses like colour blindness.

Option D:

1. The totality of all the population members' genes in an inbreeding population is referred to as the gene pool.
2. The frequency of different genotypes in the gene pool will depend on the percentage of each genotype in the small isolated tribal community.
3. Because the population is isolated, the genes are restricted to that region alone, and no genes from outside can get in.
4. As a result, they won't have a huge gene pool.

Final answer: In isolated small tribal populations, there is a decline in population as boys marry girls only from their own tribe