A) A textbook definition would be that genetic drift is: a random change in allele frequency caused by a series of chance occurences that cause an allele to become more or less common in a population. In layman's terms, this means that genetic drift happens when luck makes the genetic pool of the population to deviate from what is expected.
B) The cause for this genetic drift is the aformentioned couple. Because amish communities are small and they select partners from their community, having even a couple of carriers of alleles in a community can make the allele freuency much larger than expected; for example, if the community was 100 persons, the percentage would be in the order of 1%, still much larger than the general population. Thus, the cause here is that a small population had a couple of carriers.
C) Sexual reproduction leads to a mixing of alleles from both mother and father and helps diversity. When a population is isolated, the gene pool is fixed and no new genes can come in, reducing diversity. Also some people that have an allele might die, hitting diversity even more. Finally, having a small population creates a strong pressure in some circumstances that leads to elimination of some traits and diversity.
Answer:
1. Are usually single-celled.
2. Do not contain membrane-bound organelles
3. Have DNA located in cytoplasm
Explanation:
Prokaryotic cells are single-celled organisms which have the following characters:
1. They lack a true nucleus and hence, they do not have their genetic material enclosed in a nuclear membrane-bound nucleus, rather it is present in the cytoplasm.
2. They lack all the membrane-bound organelles such as mitochondria, endoplasmic reticulum, etc.
3. They are usually. very small in size and hence are microscopic.
Examples include all the bacterias.
Answer:
Explanation:
an example is the ability to endure the sugar, lactose, in milk. In many places of the world, people can't drink milk in light of the fact that their body turns off the intestinal creation of lactase, a chemical that processes the sugar in the milk.
