Lecture 6A

Lecture 6A - 1/27/09 Lecture 6 Phylogenetic trees Reading...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1/27/09 1 Lecture 6 Phylogenetic trees Reading Ch 26 Overview I. What is a phylogeny? II. History III. How do we read trees? IV. How do we build trees? A. characters B. reasons for similarities 1. homology 2. homoplasy 3. shared & derived homologies C. tree building techniques 1. outgroup comparisons 2. parsimony 3. maximum likelihood V. Is there such a thing as a fish? VI. Why are phylogenies useful? VII. Molecular clocks I. Phylogeny = evolutionary history of a group of species Phylogenetic tree – picture of that evolutionary history *branching diagram *shows relationships among taxa *recency of common ancestor Phylogenetic trees - must be inferred Reconstructing the past we didn’t see Hypothesis – can change Systematists - those who study the evolutionary relationships among organisms (systematics ) Use all possible types of data (external and internal morphology, behavior, cell structure, chromosome #, nucleotide sequences in DNA, etc.)
Background image of page 1

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

View Full DocumentRight Arrow Icon
1/27/09 2 II. History the classification of organisms – very old Carolus Linneaus (1707-1778) Swedish botanist binomial naming system hierarchical categorization point - understand God’s plan Phylum : Arthropoda Class : Insecta Order : Diptera Genus : Musca Species : domestica Kings Pour Coffee On Fairy God- Sisters Darwin gave this system an explanation: hierarchical classification reflects historical events (descent from a common ancestor) Mammals - hairy because descended from hairy ancestor (1837) 1st -known sketch by Darwin of an phylogenetic tree For the most part - classification represents real history of evolution For the most part - organisms that look more alike are more closely related But NOT always true… elephants manatees and dugongs hyrax
Background image of page 2
1/27/09 3 Example - birds and crocodiles more closely related
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

Lecture 6A - 1/27/09 Lecture 6 Phylogenetic trees Reading...

This preview shows document pages 1 - 4. Sign up to view the full document.

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