Phylogenetics+Lab+exercise+03

First draw pictures of each of the organisms in your

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Unformatted text preview: of lineages that share the derived form of this character, an amniotic egg (A, below), and hypothesize that they form a clade (B): We go through the whole table like this, grouping clades according to derived characteristics (C): 5. Work out conflicts that arise. There are no conflicts here. Every group is a subset of another group (see C above). 6. Build your tree. Based on the groupings above, you produce this tree: 7. Voilà! You have made a phylogeny. Of course, this was just an example of the tree ­building process. Phylogenetic trees are generally based on many more characters and often involve more lineages. For example, biologists reconstructing relationships between 499 lineages of seed plants began with more than 1,400 molecular characters! Prelab questions: 1. Describe the three primary assumptions of cladistics. 3. Draw a simple phylogenetic tree for two sister clades with a common ancestor. Each sister clade consists of two taxa. Define the following terms and use them to label your diagram: clade, node, branch, common ancestor, and taxon. 4. What is a dichotomous key and it’s purpose? Laboratory Objectives • Identify two different species of fish using a dichotomous key. • Create a dichotomous key to describe a group of organisms. • Understand the use of phylogenies and reconstruct a phylogeny using a group of taxa. Lab Activity 1 – Dichotomous Key Exercise 1. Draw a picture of the given fish. 2. Use the given four fish and use a dichotomous key to describe each sample. Below write down the species number, what you identified it to be, and the steps used to identify it (ex. 1b, 3a, 4a, 5b. Fish # Identified as…. Identification pathway 3. Using the given taxonomic groups. Construct your own dichotomous key to identify the different tax...
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This homework help was uploaded on 02/19/2014 for the course BIO 1B taught by Professor Carlson,mischel,power during the Spring '07 term at University of California, Berkeley.

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