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Special Topics in Evolution

Special Topics in Evolution

The Theme of Unity and Diversity in Special Topics in Evolution

Evolution is, by definition, a study of diversity in groups. In the previous theme, we talked about the various types of organization: population, organism, cellular, genomic. At each level there is a diversification of character: organism changes in the population, cellular or genetic changes in the organism, genomic changes in the cell, or DNA changes in the genome. Interestingly, all of these changes increase the diversity within the level of organization. Increases in diversity increases the success of the population, organism, cell, or genome as a whole.

Since mutations will arise due to spontaneous errors in DNA replication, some mutations will be fixed in organisms. Those organisms that survive to have offspring will also acquire mutations. If you look at a field of cows, even if the cows are all related to each other, each cow will have a slightly different genetic sequence from the other cow. The variation from cow to cow generally allows for better fitness for cows. If a disease targets certain cows, than cows with slightly different genetic sequences might be resistant. This is why diseases as effective as influenza or HIV will never truly wipe out the human population. Our diversity guarantees that some people will be resistant to a lethal pandemic. Our diversity brings about unity of the group by improving the fitness of the group overall.

The study of biodiversity is becoming increasingly more important as evolutionary biologists begin to understand the importance of diversity in the environment.

It is estimated that human activities will make 100-1000 times more species go extinct than occurs at a natural rate. Check out the major extinctions over the last 500 million years here. While evolution is the process of natural selection, the last 10-20 thousand years marks a new era in evolution driven by artificial or human selection. Species most capable of survival in this era are the ones who are best adapted to the damage that we create in the environment with our activities.

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