Lec 26 - BIS2B Fall 2009 (Keen) Lecture 26 . Speciation 9...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: BIS2B Fall 2009 (Keen) Lecture 26 . Speciation 9 November Concept of a lineage, anagenesis, extinction, stasis, cladogenesis and reproductive isolation. Students should be able to: Describe the four fates of a lineage over evolutionary time predict the effects of gene flow on population differentiation explain the process of cladogenesis outline and illustrate 9 mechanisms of reproductive isolation What is a lineage? • A group of organisms connected by descent from a common ancestor. • This slightly vague definition is useful at a range of levels • your family is a lineage, your ethnic group is a lineage, the human species is a lineage; all primates form a lineage, all mammals form a What is a lineage? • A group of organisms connected by descent from a common ancestor. • This slightly vague definition is useful at a range of levels • your family is a lineage, your ethnic group is a lineage, the human species is a lineage; all primates form a lineage, all mammals form a lineage, all chordates form a lineage. Then Now TIME A genetic lineage Four possible fates of a lineage Total phenotype Time Now stasis anagenesis extinction cladogenesis Then What kind of selection would produce anagenesis? What kind of long-term selection would result in stasis? • a. Directional selection • b. Divergent selection • c. Stabilizing selection • d. Sexual selection • e. Frequency-dependent selection There are many definitions of a species • The biological definition of a species is a group of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups. This means that fertile hybrids between two species do not form or persist....
View Full Document

This note was uploaded on 04/21/2010 for the course BIS 2C BIS 2C taught by Professor Rizzo during the Winter '09 term at UC Davis.

Page1 / 28

Lec 26 - BIS2B Fall 2009 (Keen) Lecture 26 . Speciation 9...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online