Animal Behavior (Ethology) and Evolution Unit 8 Animal Behavior (Ethology) and Evolution

Day 3 Evidence of Evolution

Evolution Change in a population over time

Evolution theories Lamark- use and disuse The more a structure is used, the bigger and better it gets Structures not used, decrease and disappear These traits (acquired characteristics) that develop during life are passed to offspring but not through genes

Evolution theories Darwin- Father of Evolution Origin of Species- book that discussed the theory of natural selection “Survival of the Fittest”- organism best suited to the environment will survive and reproduce and pass traits to the next generation

Natural selection Organisms most fit to environment survive and reproduce passing these adaptations to the next generation Ex: Runt of the litter is the least likely to survive Ex: Peppered Moth of England Color was white until the industrial revolution left light bark trees dark. Species mutated to the dark colored moth due to camouflage

Natural selection Variation: Caused by sexual reproduction Occurs within a population when it needs to adapt to environment Caused by gene shuffling during fertilization and crossing over or when a positive mutation occurs Over-reproduction: more offspring are produced in each generation than can survive Competition: Due to individuals living in the same area and having the same niche (job)

Evidence of Evolution Fossils Old layers in lower rock layers, new fossils in upper rock layers Fossils tell that fewer organisms were on Earth in earlier eras and that they were less complex

fossils Form in sedimentary rock Imprints, molds, casts, petrified fossils Relative age of fossils can be determined from the layer of rock the fossil is in Old fossils in bottom layers and young in upper layers Absolute age- radioactive isotopes, carbon 14, half life

Evidence of evolution Comparative Anatomy Vestigial structures- have no function Ex: Appendix, pelvis of a whale Homologous Structures- looks the same but have different functions Ex: bones in the hand and flippers Analogous structures- look different but have the same function Ex: wings of a bird and insect

Evidence of evolution Embryology- study of embryos Compare embryos of different species at different stages of development More alike, more related

Evidence of evolution Biochemical comparison #1 thing scientists use to group/ classify based on evolutionary relationships Compare organisms proteins and their DNA Only 1% difference in the DNA or a chimp and a human