4 FEBRUARY 201423_BIO130_0204142/04/2014Bio 130 TR 12:40-1:55p Lecture 8- Use the lecture review questions to study for the exam- Exam in 9 days!!!- Pick up your graded quiz from your lab instructors this week- Darwin day February 10-12thSpeciation- BIG IDEA: EvolutionObjectives- Understand how species are defines- Explain how species arise- Explain the difference between allopatric and sympatricWhat is a species? Three concepts:1. Morphological (size, shape, color, pattern)2. Biological (ability to reproduce viable offspring naturally)3. Phylogenetic (genetic similarities)The process of speciation requires genetic isolation and divergence via selection, drift and/or mutation. Divergence is caused by geographic separation (allopatric) or niche or habitat isolation (sympatric). Allopatric speciation comes by dispersal (founder effect) or vicariance (geographical barriers). Sympatric speciation example: Jamaican anoles were separated by position (niche) in a canopy within a forest habitat (disruptive selection). A niche is a range of resources that a species can use and range of conditions it can tolerate. The next step in speciation is reproductive isolation. The species cannot produce viable, fertile offspring and speciation is complete. Specific mechanisms that prevent the production of viable offspring are gamete incompatibility, lack of sexual attraction, behavioral differences, different habitats or they cannot biologically reproduce. Prezygotic (prevent mating or successful fertilization)- Habitat: breed in different habitats- Temporal: breed at different times- Behavioral: unique courtship displays- Mechanical: male and female genitalia incompatibility- Gametic: gametes are incompatible, the sperm cannot fertilize the eggPostzygotic (fertilization, but prevents fertile offspring)- Hybrid viability: offspring die as embryos- Hybrid sterility: offspring survive, but are sterileEvolutionary Processes (review for exam)Four processes of evolution4 FEBRUARY 20141. Natural selection (sexual selection) Requires natural variation, heritability and differential reproduction2. Genetic drift3. Gene flow (requires reproduction in the recipient population)4. MutationTypes of mutations:- Change in a nucleotide base, can create a new allele- Gene duplication (multiple nucleotides are copied and cause a redundant gene)- Mutation in the regulatory region (switch) of a geneMutations increase genetic diversity, it can have a positive or negative effect on