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In lectures you heard a number of times about the vast diversity of life that has evolved over the past few billions years. We discussed life in its major domains and spent a some time on the major eukaryotic groups—plants and animals. We explained the idea of natural selection as the major force creating this diversity and mentioned Darwin and Wallace as the major contributors to this scientific hypothesis. We looked at the “family tree” of birds and hypothesized why, despite being overall similar, they have notably different beaks! They descended from a common ancestor, and show selection for beaks that helped them eat different prey, reproduce, and maintain this helpful variation. This is the explanation for evolution and for extinction.
Something to ponder: while the diversity of animals seems nearly endless, today the Earth is experiencing the greatest mass extinction in its long history. During this lab period, 20 species will probably go extinct, mostly due to habitat loss and degradation of the environment. Most of these are considered small and unimportant by many people. However, I do not know what is “unimportant” and why our species is more important then others...