Natural Selection, Geological Formations, and Ecology

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Concepts

1. The Hardy-Weinberg theorem states that the sexual shuffling of genes is an inadequate means of evolutionary change. The reasoning is that, if there is no environmental pressure to change, then the genes in any individual will not be any more or less favored than they were in previous hosts.

2. Genetic drift refers to changes in the gene pool of a small population due to chance, including mutations.

3. The stabilizing section favors intermediate variants by acting against extreme phenotypes. Directional selection favors one extreme phenotype over others. Disruptive selection favors extreme phenotypes in general over intermediate variants.

4. Layers of sedimentary rock allow a scientist to date a fossil discovered within a certain rock formation by determining the age and geochronology of the rock formation.

5. A forested biome will typically be a semi humid, temperate area. Its inhabitants include many mammals and birds, warm-blooded creatures to handle the winter. A coral reef will be a tropical, aquatic biome that finds many fish, crustaceans, and corals adapted to saltwater. A desert biome will be an arid area, with organisms such as snakes and scorpions evolved to handle the dry, hot environment.

6. An ecosystem refers to the biological interactions, direct and indirect, within an area and the biome refers to the area united in biological processes itself.

7. The primary consumer elevates the resources gathered by the producers so that they are accessible to predators. In addition, they provide a natural selection for producers.

8. An ecological niche is the sum of an organism’s utilization of the biotic and abiotic resources of its environment. Competitive exclusion is the process of eliminating one species when it competes with a more advantageous species over the same niche.