Theme 2: EVOLUTION
Description: Biological change of organisms that occurs over time. Which is driven by the process of natural selection. Evolution accounts for the diversity of life on Earth.
Clarification: You would post here examples of evolutionary change in populations of organisms that we have been able to observe or have evidence of.
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Many organisms possess vestigal structures that have no apparent function but resemble structures their presumed ancestors had. The skeleton of a whale reveals the presence of pelvic bones. These bones resemble those of other mammals, but are only weakly developed in the whale and have no apparent function.
Heterozygote advantage is when heterozygotes are favored over homozygotes and if this happens than natural selection will tend to maintain variation in the population. We see this in Africa where their are more heterozygotes who possess an allele for sickle cell anemia,50% of their red blood cells are sickle. Homozygous dominant die of malaria while homozygous recessive die of sickle cell anemia. However, heterozygotes are relatively free from both malaria and sickle cell.
Bacterias resistance to Penecillin can also be used to demonstrate evolution. Evolution when defined as a change in species over time is very easy to see and very uncontroversial UNTIL we add Humans into the equation.
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