BIOLOGY 1101 Lecture Notes - Lecture 16: Radiometric Dating, Reproductive Isolation, Genetic Divergence
21 Oct 2016
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Thursday 10/20: estimated age of earth, 4. 5 billion years (radiometric dating), phase 1. The formation of small molecules containing carbon and hydrogen. Earth"s atmosphere had almost no oxygen and was filled with many compounds released during volcanic eruptions. Populations of organisms that interbreed with each other, or could possibly breed, under natural conditions. Reproductively isolated from other such groups: two key features. One species splits into two distinct species. Requires more than just evolutionary change in a population. Barriers that prevent offspring from being conceived. Hawthorne/apple maggot flies: hawthorne/apple maggot flies. Introduction of apples to n. america provided new habitat for larvae. Offspring tend to lay their eggs in the same type of fruit they hatched in. Hypothesized this could lead to biologically distinct species: species are not always easily defined. It may not be possible to identify an exact point at which the change occurred.
