BIS 2C Midterm 1 notes!

BIS 2C Midterm 1 notes! - Lecture # 1: Introduction to the...

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Lecture # 1: Introduction to the tree of life The tre of life refer to the concept that all living organisms are related to one another through shared ancestry This evolutionary history--or phylogeny--can be represented by a kind of branching diagram called a tree A tree is a simplified model of genealogy of life Phylogeny is a unifying principle: all organisms are linked to one another through their shared evolutionary history The tree of life is a ~4 billion year history of evolution Phylogenetic trees allow us to trace the history of changes in morphology, behavior, geographical distribution and other features of interest in a group of organisms Phylogentic trees sometimes reveal surprising relationships that give new insight into the history of life on planet Earth Phylogeny of dinosaurs demonstrates that they did not go completely ectinct Phylogentic trees allow us to predict similarities and differences among organisms Lecture # 2A and 2B: Tree Concepts Terminal taxa-real organisms that we’re interested in understanding the relationship between Internal nodes-hypothetical ancestral taxa (ancestors) Internal branches-branches connecting internal nodes Root node-the common ancestor of all taxa in the tree Each internal node splits into two branches But sometimes we draw trees in which some nodes have three or more descendant branches. Such nodes are called polytomies and they usually reflect uncertainty
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This note was uploaded on 08/15/2011 for the course BIO SCI 2c taught by Professor Maloof during the Winter '09 term at UC Davis.

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BIS 2C Midterm 1 notes! - Lecture # 1: Introduction to the...

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