Evolution Review for UNIT TEST Hint, Wink, Nudge, Do a Dance Inhabiting the Earth • Big Bang Bacteria Plants Plant – Eaters Meat Eaters Darwin • The process of Natural Selection – the biological mechanism that promotes the evolution of a species. Genetic Variation • Needed for Natural Selection to occur. • Can be caused by a mutation or genetic recombination. Darwin’s Observations • Darwin noted similarities between species living on the Galapagos Islands and those living on the Coast of South America. • Finches, plants, iguanas His Explanation • Ancestors of similar species migrated from South America to the Galapagos Islands. Adaptations • Animals and plants develop characteristics that allow them to survive (eat, maintain homeostasis) and reproduce. Competition The land iguana and the marine iguana have different adaptations and occupy different niches in order to reduce competition between the two. Invasive Non – Native Species • If a non-native animal is introduced to an ecosystem, the native species must adapt. Coevolution • Animals that evolved at the same time will have different adaptations that allow them to occupy different niches. Evidence of a Common Ancestor • • • • • • Fossils (Transitional Forms) Carbon Dating Homologous Structures Vestigial Structures DNA Fingerprinting Embryo Development • All of these show the relatedness among a species. Carbon Dating • The half-life of carbon – 14 is 5,730 years. If an organism containing one gram of carbon – 14 in its tissues died about 17,000 years ago, how much carbon-14 is left in its bones? Relative Dating • No! It is not dating your relatives. • It is looking at rock layers in order to determine the relative age of the rock. Homologous Structures • Same structure, different function • Evidence of a common ancestor Embryology • Embryology shows us the at early stages all vertebrates have the same characteristics = common ancestor. Transitional Forms • Intermediate stages found in the fossil record between the common ancestor and the present stage of an organism. Kettlewell’s Experiment • Before the industrial revolution there were many white moths, and very few dark moths – because the trees were white. After the Industrial Revolution The trees are covered in soot, so white moths are more easily seen and get eaten, leaving dark moths to survive and reproduce. Increase in dark moths due to natural selection Kettelwell’s Hypothesis • Based on his observations, Kettelwell hypothesized that moths whose body color matches the color of the tree bark are more likely to survive. Evolution of the Horse Summary: Horses have undergone several changes that are evident in the fossil record. Classification • • • • • • • Kingdom Phylum Class Order Family Genus Species Classification Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Perissodactyla Family: Equidae Genus: Equus What makes a species? • In order for two organisms to be considered members of the same species they must be able to produce fertile offspring. Hominid Evolutionary Tree Able to determine the ancestors of human. Evolution of Primates • Paleontologists can distinguish an ape skull from a human skull by the size of the cranial cavity. • Several species developed and then became extinct, leaving no descendants. • Fossil evidence suggests that human beings did not evolve from modern apes. Comparing Amino Acid Differences Number of Amino Acid Differences when compared to human hemoglobin = 0 They are most closely related to humans. Artificial Selection • When HUMANS intervene. • Change the genes of plants or animals.