each of the following refers to one aspect of evolution. explain each in terms of natural selecton.?

Question

1)convergent evolution and the similarities amoung species in a particular biome
2)insecticide resistance
3)speciation and isolation
4)heterozygote advantage

Answer 1

1. When species live in the same biome, they have similar environments, similar habitats, and similar needs. Convergent evolution can cause unrelated species to evolve similar adaptations to fit these similar needs.
2. When insecticides are used on a population, many of the insects are killed. Those that are able to to withstand the insecticide survive, reproduce, and are likely to pass on that favorable variation to their offspring.
3. Isolation is necessary for speciation to occur. Isolation can be reproductive or geographic. In either case a population doesn't interbreed with the main population, so any variations that arise are not shared with the main population. After many generations the isolated population has accumulated so many differences that the two populations can no longer interbreed, even if they are in the same area. They have become separate species.
4. Heterozygote advantage is when the heterozygotes have a better chance of surviving than either the homozygous dominant or homozygous recessive individuals. Sickle cell is an example of this. Individuals who are homozygous for sickle cell have sickle cell disease and are likely to die from the disorder. Individuals who are homozygous for normal hemoglobin do not have sickle cell disease or trait, but they may die from malaria. The heterozygotes have sickle cell trait. Since sickle cell trait is codominant, these individuals have some hemoglobin that sickles and some that does not. The malaria parasite gets into the red blood cells, actively uses oxygen in the red blood cells, and causes the infected red blood cells to sickle and die. The parasites die too. So sickle cell trait, the heterozygous condition, offers protection against malaria while not causing the more serious sickle cell disease.

Answer 2

It is simple..
Plants in a close area, ( particular biome) tend to evolve similarly. These plants will survive, because they have developed defences to help them survive..the same in the animal and insect world.. Some butterflies mimic other more poisonous butterflies in their appearance, because they know that birds will not eat them because they are toxic..
Plants develope resistance to insects by producing toxins in their cells.. Hemp is very successful at this..there are not too many insects that can destroy the plant..they are very insect resistant.
Heterozygote advantage ensures the survival of certain genetic traits.. These are fitter bigger better faster and can out perform the dominant heterzygote genome... not always for the better either.. but it is basically survival of the fittest.

Answer 3

Try reading the book "Did man get here by evolution or creation?"