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# Bio 1M: Evolution by natural selection ## 1 Evolution - The theory of evolution has replaced the theory of special creation in science. - The theory of special creation asserts that each species is a unique “type”, created by God. - The theory of evolution asserts that species have changed throu...

# Bio 1M: Evolution by natural selection ## 1 Evolution - The theory of evolution has replaced the theory of special creation in science. - The theory of special creation asserts that each species is a unique “type”, created by God. - The theory of evolution asserts that species have changed through time (evolved). - Does this mean that scientists don’t believe in God? - Can scientists believe in God? ## 1.1 Change through time ### Fossils - A fossil is a physical trace of an organism that lived in the past - Fossils can be dated using (complicated) radiometric and geological techniques - Fossils provide information about the history of life - The fossil record refers to the collection of all known fossils ### Extinction - Many fossils have been left by organisms that are no longer around - We say such organisms are extinct - Extinction is one piece of evidence that species are changing - In a very limited way - How convincing is it as support for the theory that species got here by gradual evolution? ### Transitional forms — Fig 22.22 - When a species disappears from the fossil record, a similar species often appears - This often happens in the same geographic area — Fig 22.22 - Consistent with species evolving: changing through time ### Vestigial traits - A vestigial trait is a structure that has no function, but is similar to functioning structures in related species - Examples? ### Directly observed evolution - Although much evolution occurs very slowly, some kinds of evolution can be, and have been, observed on faster time scales - Ground finches — Fig 20.8 - Tuberculosis - E. Coli — Fig 1.17