1. Evolution- Chapter 10
Process of biological change that results in descendants being different from their ancestors

2. Early Scientists Linnaues- developed classification system
Leclerc de Buffon- argued that species shared ancestors & that the Earth was much older than 6000 years- which most scholars believed
Eramas Darwin- proposed that all living things were descendants of a common ancestor
Lamarck- proposed that all organisms evolved toward perfection and complexity due to environmental changes (long neck of giraffe)
Charles Darwin- developed Theory of Evolution

3. Theories of Geologic Change
Catastrophism- natural disasters that changed Earths landform resulted in species to become extinct; a different species would move into the area
Gradualism- landforms resulted from slow changes over a long period of time;
Uniformitarianism- geologic processes that shape Earth are uniform through time and that they have occurred at a constant rate and are ongoing

4. Darwin’s Observations
Variation of traits among similar species; Variation-differences in traits
Species from one island looked different from those on nearby islands in the Galapagos Island chain.
Examples:
Saddleback tortoise-long necked lived in area with tall plants
Dome-backed tortoise- short neck lived in wet area with short plants
Adaptation- a feature that allows an organism to better survive and reproduce in its environment

5. Fossil and Geological evidence
Fossils (Paleontology) of huge animals that are similar in appearance to modern animals
Fossils of marine (sea) animals on the top of mountains
Geography-Organisms change to their environment; Species that get separated from each other develop adaptations that favor their environment
Developmental Similarities (notochord, dorsal nerve cord, pharyngeal arches (face in humans, gills)
Homologous structures- hand, bat wing
Analogous structures-perform similar functions (wings of bat to wings of fly)
Vestigial structures- organs not used ( appendix)

6. Theory of Natural Selection- Darwin
Artificial Selection- humans a species by breeding it for certain traits – selective breeding (pugdoodle, racehorses)
Natural Selection- individual organisms that have inherited a beneficial adaptation tend to produce more offspring than other organisms of that species.
Population- all the individuals of a species that live in an area

7. Main Principles of Natural Selection
Variation-inheritable differences in a population that come from changes in genetic material by beneficial traits passed on or by mutation
Overproduction- many offspring increase chance of survival of species; also results in competition for resources
Adaptation- beneficial trait that gives species an edge on competition; live longer & more offspring
Descent with modification- over time, natural selection will result in species with adaptations that are well suited for survival and reproduction in an environment.

8. Evolution of Populations – Chapter 11
Genetic variation- more variations in the gene pool the better chance of survival (gene pool- combined alleles of all individuals in a population)
Mutations or Recombination during meiosis (crossing over)

9. Distribution of Traits
Normal Distribution- the frequency is highest near the mean value
Directional Distribution-favors phenotypes at one extreme of a trait’s range drug resistant bacteria
Stabilizing Selection- intermediate phenotype becomes more common
Disruptive Selection- both extreme phenotypes become more common

10. Other Mechanisms of Evolution
Gene flow- the movement of alleles from one population to another; increases genetic variation (which helps with survival of species)
Genetic Drift- a change in allele frequency due to chance; causes a loss of genetic diversity
Bottleneck effect- event reduces size of population (overhunting, catastrophe)
Founder effect-small number colonize a new area (Amish )

11. Origin of Life Hypotheses
Organic molecules were produced from lightning passing through atmosphere of methane, ammonia, and water vapor (miller-urey experiment)
Organic molecules arrived by meteorite

12. Radiation (spreading out) of Multicellular Life
Paleozoic- multicellular organisms first appeared; Cambrian explosion-huge diversity of animal species evolved
Mesozoic- Age of Reptiles
Triassic- earliest crocodiles and dinosaurs and first animals; ended in mass extinction
Jurassic- radiation of other dinosaurs; many underwater dinosaurs
Cretaceous- ended in mass extinction of dinosaurs
Cenozoic-65 million years ago to today- mammals radiate to all parts of earth

13. Cladograms