Question

1. Explain why negative or harmful mutations have no role in the evolution of a population.
2. How do pseudogenes offer evidence in support of evolution?
3. Give an example of the bottleneck and founder effects.
4. Explain how bottleneck effect has affected cheetahs.
5. If variation in a species was only due to meiosis, how would that limit the evolution of that species?
6. If it is survival of the fittest, explain why organisms would show altruistic behaviour or kinship. For example, why would lions group together as a pride?
7. Explain how altruism and cooperation are not contrary to evolution.
8. Explain how cumulative selection allows for more detailed structures.

Answer 1

Ans 1) Negative or harmful mutation donot have any role in evolution of population because harmful mutation is among those mutations that occur during a person's lifetime and cause harm to body cells but are generally non heritable, so natural selection cannot play a role. Example of harmful mutation is cystic fibrosis which only causes harm to the individual suffering with it, is neither spreadable nor heritable (in almost all cases). Thus such mutations that are not heritable cannot play a role in the evolution of a population because for a population to evolve, transfer of genes from one generation to other is extremely important.

Ans 2) Pseudogenes are DNA sequences that resemble protein coding genes but are not transcribed to a mRNA in a way that could be translated into some functional protein. Many have suggested that pseudoy are simply molecular fossils that illustrate and provide evidence for evolutionary history.

Ans 3)

Example of bottleneck effect:-

As the size of bottle reduces moving upwards from his base to its neck, similarly if a pool of population decreases from very much to very less, in the pattern of a bottleneck, is called as bottleneck effect. Example of bottleneck effect is the reducee population of cheetah's that were in very much abundance in the previous centuries.

Example of Founder effect:-

The Afrikaner population of Dutch settlers in South Africa is desended mianky from a few colonist. Today the Afrikaner population has a an unusual high frequency of the gene that causes Huntington disease because those original dutch colonists just happened to carry that gene with unusual high frequency. This effect is easy to recognize in genetic diseases.

Ans 4) the bottleneck effect has caused the cheetah's to mate within their own relatives or it can also be said that bottle neck effect has caused inbreeding among cheetah's.