BIOM 182Bang, Michel(Christofer)2013 SpringWeek 7Lecture 16February 22Ecological Species Concept- Defines a species in terms of it’s ecological niche- A species’ niche depends on its unique adaptations to its role in the biological communityGenealogical Species Concept- Defines a species as a set of organisms with a unique genetic historyMorphological Species Concept- Defines a species in terms of its unique structural features (its morphology)Conceptually, two paths to speciation1. Two populations become so different that they are considered different species2. A population becomes so different from its ancestral state that it is considered another speciesPatterns of SpeciationAnagenesis (phyletic evolution)- Accumulation of changes with the transformation of one species to another- Process can lead to change within a population (species)- No increase in number speciesCladogenesis (branching evolution)- Branching off of one or more new species from a parent species that continues to exist-Increase the number of species-Hence, and increase in biological diversity -E.g., adaptive radiationAllopatric SpeciationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Population splits into two geographically isolated groups2. Genetic changes accumulate3. Cumulative differences prevent breeding between individuals of the two populations4. Two species have evolvedSympatric Speciation- Populations are in the same physical area- But become genetically isolated by genetic events- Or behavioral or other isolating mechanismsParapatric Speciation- Contiguous populations- But individuals more likely to mate with local neighbors- Helped by heterogeneous environment and disruptive selectionTypes of Reproductive IsolationPrez yogtic Barries- Impede mating between species or hinder fertilization if mating is attempted- Habitat Isolation- 2 species live in different habitats (in the same area) and rarely meet- Behavioral Isolation- Species do not recognize signals or mating cues of other species- Temporal Isolation-Species breed at different times (times of a day, seasons)- Mechanism Isolation- Species are anatomically incompatible- Gametic Isolation- Species gametes are incompatiblePost zygotic Barriers- If fertilization occurs, presents hybrids from developing into a viable, fertileadult- Reduce hybrid viability and fertility- Hybrid Breakdown- offspring of hybrids have reduced viability or