Speciation I. Microevolution and

macroevolutionII. Patterns of descentIII. Species concepts

A. Biological speciesB. Ecological speciesC. Morphological speciesD. Phylogenetic species

IV. Barriers that lead to speciation

A. PrezygoticB. Postzygotic

V. Modes of speciationA. Allopatric speciationB. Sympatric speciation

II. Patterns of descentA. Anagenesis

B. Cladogenesis

III. Species conceptsA. Biological species

C. Morphological species

‘Species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from each other.’ Mayr

B. Ecological species

niche

Reproductive isolating mechanisms (RIMs)

D. Phylogenetic species

• Molecular clocks

• A species consists of a population or group of populations that share a common evolutionary fate through time.

Fossil record

DNA - DNA hybridization

98.7%

99.2%

• promiscuous

• ecotypes• fossil record

III. Species conceptsProblems with definitions

• asexual species

Link

• convergent evolution

IV. Barriers that lead to speciationA. Prezygotic barriers

1. Habitat isolation

2. Behavioral isolation

• sexual selection

Sage grouse Songbirds

3. Temporal isolation

4. Anatomical isolation

5. Gametic isolation

• diurnal, nocturnal, crepuscular

A. Prezygotic barriers

B. Postzygotic barriers

wheat rye

triticale

mules

Hybrid problems

V. Modes of speciation

A. Allopatric speciation

Bird species

A. Allopatric speciation

Founder effect

Fruit flies

Darwin’s finches

Beak of the finch

B. Sympatric speciationPolyploidy in plants

• autopolyploid 2N X 1N

• allopolyploidyGoatsbeard

VI. Punctuated equilibrium• Allopatric model

• tempo of PE

Feathers and bones

VII. Evolutionary noveltiesExaptations

Evo-devo Genes

HOX genes

Gene regulation

The end