My AP Biology ThoughtsEpisode 7Welcome to My AP Biology Thoughts podcast, my name is Victoria and I am your host for episode #7 called Unit 7 Evolution: Evidence of Evolution. Today we will be defining the 4 Pieces of Evidence for Evolution, giving examples of each, and making connections to the unit of evolution. Segment 1: Introduction to Evidence of EvolutionWhat is evolution?A change in the allelic frequencies of a gene pool Continuous 4 Pieces of Evidence of Evolution - Fossil Recordthe preserved remains of traces of any organisms from the remote past, included both discovered and undiscoveredOnly the hard parts of an organism are preserved Fossil evidence can be either Direct (body fossils): bones, teeth shells, leavesIndirect (trace fossils): footprints, tooth marks, tracks, burrowsLike timeline, different kinds of organisms do not occur randomly but are found in rocks in a consistent order, this is known as the law of fossil succession It is incomplete, and requires an unusual combination of specific circumstances for it to occur, creating many gaps in the fossil record Biogeography:Organisms located in one area of the planet are closely related than those found in other parts of the planetIt describes the distribution of organisms, over geographical areas, both in the past and presentComparative Anatomy:The comparison of the anatomic features of different species2 Key types of structures that support thisHomologous structuresDemonstrate a similar underlying anatomy due to shared evolutionary origin, but have evolved into a variety of distinct forms or speciation due to the presence of different selective pressuresThe more similar the homologous structures between the two species are, the more closely related they are likely to beAdaptive radiation through divergent evolution, as similar basic organisms have been adapted to suit various environmental niches Analogous structures