BIOL 2400 Lecture Notes - Lecture 2: Body Plan, Thomas Robert Malthus, Ernst Haeckel
13 Sep 2017
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Closely related species differed from island to island. Date, time, exact location, and name of specimen were labelled. In darwin"s time people believed all species were all fully developed and were not changing. Geological change happens really slowly, so does evolution. When migrating between islands, the finch had to adapt to a new set of conditions through years of natural selection. Tortoises differ on islands based on their food sources i. e. some have better suited mouths for eating cactus. Differences in beak shape that are all well adapted for eating food specific to their island. Alfred russel wallace proposed similar ideas about common ancestry and natural selection in a letter to darwin. Homologous trait: similar because of inheritance from a common ancestor (human arm, flipper and bat wing) Darwin"s hypothesize that whales descended from terrestrial mammals. Whales share synapomorphies (shared derived characters) with mammals such as: mammary glands, three middle ear bones, hair (in developing embryos)
