Question

17. Who is Mitochondrial Eve, and what is significant about her? Was she a real person? Explain. 18. How do organisms that only reproduce via asexual reproduction produce genetic variation? a. disruption b. mutation C. refinement d. reservation e conservation 19. Which one does not belong for Pre-zygotic barrier? a. Habitat b. Gametic barrier c. Hybrid sterility d. Mechanical e. Temporal 20. T/F A change in allele frequencies is known as microevolution

Answer 1

17. In human genetics, the Mitochondrial Eve  is the matrilineal most recent common ancestor (MRCA) of all living humans, i.e., the most recent woman from whom all living humans descend in an unbroken line purely through their mothers and through the mothers of those mothers, back until all lines converge on one woman. The holder of this title is believed by some to have lived about 150,000 years ago in what is now Ethiopia, Kenya or Tanzania. The time she lived is calculated based on the molecular clock technique of correlating elapsed time with observed genetic drift. Mitochondrial DNA is passed through matrilineal descent, all humans alive today have mitochondrial DNA that is traceable back to Mitochondrial Eve.

18. b. mutation

In asexual reproduction there is no mating or mixing of genetics. Asexual reproduction results in a clone of the parent, meaning the offspring have identical DNA as the parent. One way for an asexually reproducing species to get diversity is through mutations at the DNA level. If there is a mistake in mitosis, the copying of the DNA, then that mistake will be passed down to the offspring, possibly changing its traits.

19. c. Hybrid sterility

Pre- zygotic barrier are causes through which there is no fertilisation occuring between the two organisms. All the other given option are barriers which will cease the mating of the two organisms. However, hybrid sterilisation shows there has been mating with a viable offspring produced though sterile which is case of post zygotic barrier.

20. Microevolution is the change in allele frequencies that occurs over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift.

Suppose you sample a beetle population this year, and determine that 80% of the genes in the population are for green coloration and 20% of them are for brown coloration. You go back the next year, repeat the procedure, and find a new ratio: 60% green genes to 40% brown genes. You have detected a microevolutionary pattern: a change in gene frequency. A change in gene frequency over time means that the population has evolved.