lecture19 - BioEE 278 Evolutionary Biology WHAT ARE...

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BioEE 278 Fall 2007 Evolutionary Biology Lecture 19 WHAT ARE SPECIES? Reading: Ch. 15 A. Questions to consider 1. What is a species, what is speciation? 2. What are the roles of microevolutionary processes and geography in speciation? 3. What genetic changes are associated with speciation? B. Speciation as an explanation for current diversity 1. Anagenesis and cladogenesis a. Anagenesis: gradual change (microevolution) in a lineage, b. Although anagenesis can lead to very different forms, the “cut-off” between one species and the next is difficult to establish. 2. Cladogenesis a. Cladogenesis: “Splitting” of lineages b. Diversity of life requires cladogenesis (addition of new species), not simply the replacement of one species by another. C. What is Speciation? 1. What is a species? a. Debates about species concepts b. Expect to find lineages at all stages of divergence because the origin of new species is an ongoing evolutionary process 2. Biological species concept (BSC). a. Species are "groups of actually or potentially interbreeding natural populations
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This note was uploaded on 09/28/2008 for the course BIOEE 2780 taught by Professor Geber during the Fall '07 term at Cornell University (Engineering School).

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lecture19 - BioEE 278 Evolutionary Biology WHAT ARE...

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