Class Notes (839,626)
Canada (511,431)
Biology (6,826)
Lecture 9

Lecture 9: "Speciation"

2 Pages
98 Views

Department
Biology
Course Code
Biology 3466B
Professor
Yolanda Morbey

This preview shows 80% of the first page. Sign up to view the full 2 pages of the document.
Description
Evolution Lecture No. 9: Speciation th Friday September 28 , 2012 Speciation – Defining The Undefinable: -When examining different species of the globe, each should:  Reflect morphological distinctiveness (have different or unique phenotypic qualities).  Reflect evolutionary independence (be able to survive successfully).  Be objective (and not subjective).  Be testable (in the field of its natural setting).  Be applicable to sexual and asexual forms, cryptic species (morphologically similar), fossils, etc.  Make identification easy. The Three Species Concepts: -It is quite difficult to accurately define the parameters for a species, but three concepts exist to alleviate this difficulty: -Morphological Species Concept (MSC): groups of populations with distinct morphological differences; incredibly identifiable in the field. -Biological Species Concept (BSC): groups of potentially or actively interbreeding natural populations which are reproductively isolated from other groups. -Phylogenetic Species Concept (PSC): the smallest group whose members descend from a common ancestor and who possess defining (derived) characteristics that distinguish them from other groups; shows the evolutionary relationships among different species. -In an example featuring the phylogenetic tree of various species of Eurytemora offinis around the world, they would all be part of one species according to the MSC (as they more or less resemble each other) and eight distinct species (due to 8 different nodes) according to the PSC. The Processes Of Separation: -There are three processes of evolution: -Isolating Barrier: geographic/allopatric (different place) or reproductive/sympatric (same place). -Divergence: mutation, genetic drift or selection; describes the evolutionary portion of separation. -Secondary Contact: The reinforcement of evolved differences between newly-formed species. Dispersal As A Geographic Isolating Barrier: -Dispersal represents when certain members of a species will
More Less
Unlock Document

Only 80% of the first page are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit