1. SPECIATION Ch. 16-3 pp. 326-330 Warm up 3/2: Define: Homologous Structures, Analogous Structures and Vestigial Organs/Structures. Give 1 example of each What would cause homologous structures? and what vestigial structures?

2. Forming a new species  Speciation: forming a new species  Species: a group of organisms that can mate and produce fertile offspring 1. same number of chromosomes 2. similar morphology (body structure)

3. 2 Definitions of Species  Morphological Species – Defined using similar characteristics.  Asexual organisms  Extinct organisms  Biological Species – A species can reproduce and have fertile offspring.  A group of organism that can successfully interbreed.  Cannot breed fertile offspring with other species.

4. Disruptive Selection Divergent evolution that most likely results in two new species

5. Mechanisms for speciation  Allopatric speciation caused by geographic isolation  Requires physical separation of organisms

6. Mechanisms Cont.  Sympatric Speciation due to reproductive isolation (barriers to successful breeding)  Live in the same area  Barriers to successful breeding Liger – Tiger and Lion produce an infertile offspring

7. Sympatric Speciation Cont.  Two types of Sympatric Speciation Barriers  Prezygotic: before fertilization (i.e breeding times or home range)  Postzygotic: after fertilization- infertile offspring (chromosome # doesn’t add up) Liger – Tiger and Lion produce an infertile offspring

8. Homework  Speciation activity: Due Monday

9. Homework: Tri-fold Vocab Due Tuesday 2/26 Genetic Drift Biological Species Concept Allopatric Speciation Sympatric Speciation Prezygotic Isolation Postzygotic Isolation Gradualism Punctuated Equilibrium Speciation Homework: Due Wednesday 2/27 Read p326-330 Do p 330 # 1-7 Study Guide & Raft Due Thursday Exam Friday: Intervention this week.

10. Warm up 3/3 Match and explain why. 1. 3. 2. 5. 6. 4. Red Butterflies killed in tornado. A. Gene Flow B. Genetic Drift C. Natural Selection D. Sexual Selection E. Allopatric Speciation F. Sympatric Speciation

11. Warm up 3/3 Match and explain why. 1. Gene Flow 2. Genetic Drift 3. Natural Selection 4. Sexual Selection 5. Allopatric Speciation 6. Sympatric Speciation A C B F E D

12. Rates of Speciation  Gradualism: slow divergence  Punctuated equilibrium: sudden shift in form (irregular)