MACROEVOLUTION - SpeciationThe evolution of a new, separate species

1

BioH Ch 17

Considerations

2

Reproductive Isolation Mechanisms

Pre ZygoticBehavioral

Temporal

Mechanical3

Ecological

Gametic mortality

Habitat (most common)

More Pre-Zygotic Reproductive Isolation Mechanisms

4

Post-Zygotic Isolation Mechanisms

Hybrid viability – embryonic premature death

Hybrid infertility

5

Allopatric Speciation

Geographic barriers

6

Sympatric Speciation

Species form within a population home range -no physical barriers

7

Parapatric Speciation

Neighboring populations give rise to new species

X

Hybrid

Bullock’s OrioleBaltimore Oriole

8

m. domesticus

m. musculus

9

Speciation PatternsCladogenesis – branching

lineage

Anagenesis – unbranching descent

10

Exercise

11

Patterns of Speciation

12

Adaptive Radiation

Adaptive Zones 13

14

Extinction

15