1	ORIGIN OF SPECIES
2	Speciation The origin of new species is the sources of biological diversity. “Microevolution” – changes in the allelic frequencies of a single gene pool. “Macroevolution” – evolutionary change above the species level. i.e. the appearance of feathers during the evolution of birds from one group of dinosaurs.
3	Patterns of Evolutionary Change
4	Ernst Mayr defined a Biological species as… a group of interbreeding natural populations that are reproductively isolated from other such groups a biological species is defined by the reproductive barriers that preserve its integrity by preventing genetic mixing with other species So the “Biological species concept” emphasizes reproductive isolation.
5	"Similarity between species" Similarity between species
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7	REPRODUCTIVE BARRIER This is any factor that prevents two species from producing fertile hybrids (offspring) thus contributing to reproductive isolation
8	PREZYGOTIC vs POSTZYGOTIC prezygotic - mechanisms which prevent the fusion of egg and sperm so no zygote can form. postzygotic - mechanisms that prevent a zygote from developing into a fertile adult offspring.
9	PREZYGOTIC BARRIERS HABITAT ISOLATION Thamnophis sp.
10	PREZYGOTIC BARRIERS TEMPORAL ISOLATION Eastern spotted skunk Spilogale putorius Mates in late winter Western spotted skunk Spilogale gracilis Mates in late summer
11	PREZYGOTIC BARRIERS BEHAVIOURAL ISOLATION Courtship displays
12	PREZYGOTIC BARRIERS MECHANICAL ISOLATION
13	PREZYGOTIC BARRIERS GAMETIC ISOLATION External fertilization
14	POSTZYGOTIC BARRIERS REDUCED HYBRID VIABILITY Ensatina sp. Do hybridize but hybrids don’t develop.
15	POSTZYGOTIC BARRIERS REDUCED HYBRID FERTILITY Horse X Donkey Mule
16	POSTZYGOTIC BARRIERS HYBRID BREAKDOWN In rice some F1 hybrids are vigorous but the second F2 generation are sterile
17	Limitations of the Biological species concept Applies only to sexually reproducing species –What about bacteria? What about Fossils? Other Definitions of Species Morphological Species Paleontological Species Ecological Species Phylogenetic Species
18	Speciation
19	GEOGRAPHICAL ISOLATION Allopatric speciation - occurs when the initial block to gene flow is a geographical barrier that physically isolates a splinter population from the parent population.
20	"Sympatric speciation - a new..." Sympatric speciation - a new species can originate in the geographical midst of the parent species in plants this can occur due to polyploidy. The commonly cultivated Easter lily (Lilium longiflorum) is a tetraploid (4n) hybrid. The typical haploid number for the genus Lilium is 12 (n = 12). The tetraploid hybrid has larger blossoms.
21	Autopolyploid
22	Allopolyploid
23	Nonrandom mating in Cichlids
24	"Sexual selection – females chose..." Sexual selection – females chose their mates only of their species.
25	"Hybrid Zones" Hybrid Zones
26	Hybrid Zones
27	"Reinforcement" Reinforcement
28	"Fusion" Fusion: Weakening Reproductive Barriers Lake Victoria Cichlids
29	Punctuated Equilibrium
30	"Single gene reproductive isolation" Single gene reproductive isolation