Evolution Review 2013

History of Major Events Earth is 6 billion years old Radiometric Dating: a method to establish the age of materials. Radioactive decay = half life First organic compounds ▫Urey Miller experiment were able to produce organic compounds by initiating lightening on water vapor, H2, CH4 and NH3 ▫Development of first cells– Microsphere and coacervates.

Transition of chemosynthetic, photosynthetic, and aerobic ▫Chemosynthetic used sulfur for energy– Archaea today ▫Gave rise to photosynthetic bacteria –used sun as energy source---aerobic respiration produces O2 ▫Eukaryotic organisms developed through endosymbiosis—chloroplasts and mitochondria ▫Check events that lead to aerobic life. Why did heterotrophs evolve first?

Modern Evolutionary Theory People: Explain their contribution on Darwin’s thinking ▫Darwin ▫Cuvier ▫Lyell ▫Lamark ▫Wallace ▫Malthus ▫Steno

Darwin ▫Traveled to Galapagos ▫Studied how animals adapted to environments ▫Ship: HMS Beagle ▫Book: On the Origin of Species by means of Natural Selection ▫Did Darwin know anything about genetics?

Evidence for evolution ▫Fossils ▫Species variation ▫Anatomy/embryology ▫This is very incomplete!!!!!! Check your book and the ppt. on Charles Darwin.

Species and populations Microevolution: change in the collective genetic material of a population Put in some examples here Macroevolution: the evolution of a species on a large scale. Effects the entire species Give examples

Hardy-Weinberg Genotype frequencies in a population tend to remain the same from generation to generation unless acted o by outside influences. Conditions for a stable population ▫No mutation ▫No immigration or emigration ▫Pop. Is large ▫Selection does not occur ▫Individual mate randomly

Causes of microevolution Mutation; give example Gene flow: give example Genetic Drift: give example Nonrandom mating: give example Natural Selection: give example

Variation in a population Sources: ▫Mutation: random change in a gene passed to offspring ▫Recombination: reshuffling of genes during independent assortment and crossing over. ▫Random pairing of gametes: large number and fetilizes randomly.

Single gene traits: determined by a single gene with two or more alleles Examples Polygenic traits: influenced by several genes. Examples Patterns of Natural Selection ▫Disruptive ▫Stabilizing ▫Directional ▫Be able to draw each type and explain what is happening.

Steps in speciation A species is a pop. of organisms that can successfully interbreed but cannot breed with other groups. Geographic isolation results from the separation of population subgroups by geographic barriers. Geographic isolation may lead to allopatric speciation.

Allopatric speciation: two groups become separated geographically which results in reproductive isolation because of ▫Genetic drift, ▫Mutations ▫Natural selection

Reproductive isolation: results from the separation of population subgroups by barriers to successful breeding. Reproductive isolation leads to sympatric speciation.

Sympatric speciation: two population become reproductively isolated within the same geographic area. ▫Each species occupies a different niche ▫This specialization leads to reproductive isolation.

Rates of Speciation Gradualism: species undergo small changes at a constant rate. Punctuated : new species arise abruptly, differ greatly from their ancestors, and then change little over long periods.