2 Flap #1: Fossil Evidence Fossils Show Change and agePreserved remains formed in sedimentary rock. Relative Dating compares them in different layers.The oldest fossils are at the bottom. The youngest fossils are at the topYoungest fossils at the topOldest fossils at the bottom
3 Flap #2: Homologous Structures Similar skeletal arrangement. May have different functions.Indicates that organisms share a common ancestor and DNAHomologous structures such as the arms/fins shown, are similar in arrangement. These organisms share DNA and an ancestor.
4 Flap #3: Vestigial Structures Useless organ to modern organisms, but probably was useful in ancestors (wisdom teeth, pelvic bone in whales, appendix in humans).The Pelvic bone in whales seen on the left is indicative that whales used to have legs/feet for walking. Over time the pelvic bone has gradually gotten smaller. It has no current use.
5 Flap #4: EmbryologyEmbryos of different species look similar because of closely similar DNA, RNA, and Amino Acid sequences
6 Flap #5: BiochemistryMost organisms share DNA, ATP, hormones, and enzymes. This is why organisms look similar as embryosSmall differences = closely related, shared ancestor
7 Flap # 6: Geographic Distribution Similar environments have similar types of organisms.The same species of an organism may appear different because of its geographic location.Geographic isolation: species separated by physical boundaries, limiting variation in mating. Leads to speciation.Speciation: one single species (after being isolated for so long), gives rise to another new species.An Island is a physical barrier that could separate a species. After being separated for a long time, species become physically and genetically different. This reduces mating options. When the species reunite, new species forms.