Of course we can survive without clothes. We evolved a hairless body because our ancestor was an ape that was forced to live in the hot, open savanna, where fur is not needed. In fact, many people around the world did not wear any clothes. Native Hawaiians, for example, wore no clothes when the first European explorers arrived. Amazonians and Africans also did not wear clothes. Humans evolved in Africa about 150,000 years ago, and the early humans wore no clothes. Humans started migrating out of Africa about 60,000 to 70,000 years ago. They followed the coast line and went all the way to Australia. These early migrants ended up in places that required no clothes. Only when humans migrated to places like ice age Europe and northern parts of Asia (northern parts of China, Japan and Korea) did they need to wear clothes or animal skins to stay warm. Wearing clothes blocks out the sun and these people were in danger of vitamin D deficiency, which leads to rickets. Rickets can result in muscle cramps, broken or deformed bones and even death. In order to absorb enough UV light to synthesize vitamin D, there was strong selection pressure to evolve lighter skin tones.
The habit of wearing clothes, even in places that do not require them, was spread by European Christians. Basically they forced and/or shamed the natives to wear clothes wherever they went.Of course, not wearing clothes means that humans will no longer be able to live in temperate areas around the world, at least not during the fall and winter months.
Answer:
Mainly, the number of genes that control traits.
Explanation:
Polygenic inheritance does not follow Mendel's law of dominance. According to Mendel the dominant trait will mask the recessive trait however, this is not always the case. Polygenic inheritance states that traits are controlled by two or more genes and is also dependent on the environment.
Let's take skin color for example. A fair-skinned person will have a child with a dark-skinned person.
Mendelian inheritance would assume that the offspring would either be fair or dark only.
Polygenic inheritance would assume that the offspring would be either fair, dark, or a tone in between, depending on the environment they are in as well.
Hope you understood it.
A common birth defect characterized by an opening between the upper lip and the nose is called Cleft Lip. Cleft lip happens during the early stage of pregnancy. This occurs when there is an unsuccessful connection in the face and lip area while the fetus is developing inside the womb. Both cleft lip and cleft palate are successfully treated with surgery.
Answer:
The evolutionary mechanism that could be influencing the allele frequencies between both islands and the mainland population might be Founder Effect.
Explanation:
Genetic drift is the random change that occurs in the allelic frequency of a population through generations. The magnitude of this change is inversely related to the size of the original population. These changes produced by genetic drift accumulate in time and eventually, some alleles get lost, while some others might set. Genetic drift affects a population and reduces its size dramatically due to a disaster -bottleneck effect- or because of a population split -founder effect-. In <u>founder effect</u>, a new population originates when a few individuals who are coming from a bigger population carrying its genes, settle down in a new area and reproduce. This small population might or might not be genetically representative of the original one. Some rare alleles might be exceeded or might be completely lost. Consequently, when the small population increases in size, it will have a genetically different composition from the original one. In these situations, <u>genetic variability is reduced</u> and there exists the possibility of developing a peculiar allelic composition. If the number of individuals that originated the new population is low, the founder effect will be very extreme, because the effects of the genetic drift are inversely proportional to the original number of individuals.
<em>In the exposed situation, the evolutionary mechanism that could be influencing the allele frequencies between both islands and the mainland population might be Founder Effect. The fact that both islands are similar in their frequencies might be due to little genetic variation on island 1, or because dispersion to island 2 is a recent event on time. </em>
Well, the cell would be out of energy! The mitochondria plays a very important role in cell functions. With out it, it cannot do whatever job that needs to be acquired.
