Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
Define: Homologous characters
|
Characters whose traits are shared between two or more taxa or clades because of inheritance from a common ancestor |
|
Provide an example of homology |
The pouch shared between Koalas and Possums |
|
T/F: Homologous characters can be useful in identifying monophyletic clades |
True |
|
Define: Convergence (A.K.A. homoplasious characters) |
Characters whose traits are shared between two or more taxa but evolved independently |
|
Provide an example of homoplasies |
Fins in dolphins and fish + sharks aer homoplasy |
|
Which of the following is synonymous with evolutionary convergence A. Non homologous B. Analogous traits C. Homoplasious D. All of the above |
D. All of the above |
|
Define Reversals |
A Homoplasious character in which the traits independently returned to their original (Ancestral state) |
|
Why are homoplasies not useful for phylogeny construction |
Homoplasies contain both convergence and reversals making it difficult to identify common ancestry and construct acurate phylogenies. |
|
The evolution of armor plates in cichlids were due to convergence |
False. it was due to reversal |
|
T/F: Character state changes are useful in helping to group species together |
True |
|
What is the difference between Unique Derived Characters and Shared Characters |
Unique derived characters are unique for a single clade while Shared derived characters are unique to two or more clades. |
|
What is the difference between Shared Primitive Characters and Shared Derived Characters |
Shared Primitive characters are ancestral traits shared amongst a group of clades. Shared Derived Character is a recent trait appearing in a common ancestor and in later descendants. Shared Primitive traits are not useful in determining monophyletic groups because it is difficult to determine how far back the shared primitive trait really goes. |
|
What two types of characters are not usefull in diagnosing a monophyletic group? |
Unique derived characters and shared primitive characters |
|
Also known as synapomorphis, this type of character is the only one that can be used in diagnosing monophyletic groups |
Shared derived characters. |
|
T/F: CMT1A in chimps and humans is a type of unique derived character |
False. it is a synapomorphy (shared derived character) which can infer that chips and humans are a form of monphyletic clade |
|
What are the purpose of outgroups in a phylogeny? |
To polarize primitive to derived direction of character state changes in the group |
|
Define Apomorph |
Any new derived character or trait |
|
Define Plesiomorph |
Any ancestral (old) character within a set of tax |
|
T/F: A clade is any monophyletic group |
True |
|
What method should you use in order to create a phylogenetic tree without knowing the sequence of apomorphs or know of a common ancesotr? |
1. Begin with an outgroup analysis. Choose an outgroup based on group and assume that the outgroup has not evolved relative to the ancestral condition of the group. 2. Explore possible ordering of new characters for the taxa based on parsimony |
|
Define: Parsimony |
The hypothesis with the fewest number of evolutionary changes is evolutionarily preferred. |
|
Which of the following is correct about parsimony? A. The optimal tree is the one that minimizes the sum of the lengths of all characters in terms of evolutionary steps B. A tre with the minimum length C. Provides the bet fit of the data set. D. All of the above |
D. All of the above |
|
|
A. Wings |
|
Why is it difficult to categorize whales on a phylogenetic tree |
Artiodactyls and mammals are the two groups that whales would fall under, but are unable to accurately place because of their fuse/fragmented astragalus. |
|
Describe the Distance method |
A faster method of building phylogenetic trees than parsimony |
|
Describe the process of the distance method |
1. Make pairs of species 2. For each pair, calculate the distance. the distance is the difference in character states. For DNA, it can be the number of changes required to go from one sequence to another 3. Join the species pairs following the order of shortest distance (neighbor joining) |
|
T/F: Under the distance method, closely related organisms will share more nucleotide homologies |
True |
|
T/F: Under the distance method, the greater the separation from a common ancestor, the more homologies |
False. the greater the separation from a common ancestor, the less homologies |
|
Use the distance matrix to find the closest relative to the outgroup |
Camal |
|
What are the three methods of building a phylogeny? |
1. Parsimony 2. Distance based method 3. Likelihood method |
|
Describe the likelihood method |
A probability based method of building a phylogenetic tree.
|
|
What methods are used to measure the confidence in a phylogenetic tree? |
Bootstrapping |
|
Explain bootstrapping
|
A method of measuring the confidence of a phylogenetic ree by creating artifical datasets simulated from the original data, sampling at random with replicates, and finding the best phylogeny for each simulated data. Find how many times each clade is supported among the newly found phylogeny. If it is supported 70 out of 100, the bootstrap supports the branch leading to that clade is 70% |
|
Based on the image, what is the bootstrap percent of whales and hippos |
Because they are grouped together 4/5 based on their base pairs they have an 80% bootstrap |