Phylogenetics Flashcards

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1
Q

What is microevolution?

A

Changes in allele frequencies within a population over generations

Involves a single species

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2
Q

What is macroevolution?

A

Evolutionary changes that result in different species (speciation), or higher taxa such as, family, order, phylum, etc.

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3
Q

What does a longer divergence time mean?

A

More time for independent evolutionary change and more time to accumulate differences

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4
Q

What is an inference made about relation of species?

A

More closely related species will share more similar characteristics than less closely related species because they share more evolutionary history

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5
Q

What is phylogenetics?

A

The study of evolutionary history and the relatedness of of groups

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6
Q

To consider hypotheses about evolutionary relatedness between groups, you need to be able to (2 things):

A
  1. Understand how to read a phylogenetic tree
  2. Apply this information to build a tree using data on shared characteristics
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7
Q

How does time move on a phylogenetic tree?

A

From the base of the tree (older) to the tips of the tree (newer)

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8
Q

What does the base of a phylogenetic tree represent?

A

The shared ancestor of all species on the tree

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9
Q

What do the nodes of a phylogenetic tree represent?

A

The common ancestors that all the species that branch off of it diverged from

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10
Q

How are species with more recent common ancestors related?

A

They are more closely related because they have had less time to accumulate genetic differences from each other

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11
Q

How can you determine relatedness of species?

A

By comparing most recent common ancestors

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12
Q

What is synapomorphy?

A

Shared, derived characteristics that result from a common ancestor

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13
Q

What is homology?

A

Similarity resulting from common ancestry

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14
Q

More closely related taxa will share more what?

A

Character states

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15
Q

What are character states?

A

Different forms of the characteristic

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16
Q

What is an outgroup?

A

A group with characteristics that are ancestral to the group of interest (ingroup)

17
Q

If the ingroup species have different character states for a characteristic, the character state must be what?

A

A new evolutionary feature for the group

18
Q

What are the two characteristics of synapomorphies?

A
  1. Shared, derived character states that indicate homology
  2. More closely related groups will share more synapomorphies
19
Q

What is plesiomorphy?

A

Character states found in the ancestor of the group (the outgroup has plesiomorphies

20
Q

What is apomorphy?

A

Derived character states found in descendants of the group

Evolutionary novelties acquired after divergence from the ancestral group

21
Q

When building a phylogenetic tree, what should be used to build relationships?

A

Hierarchical classification and synapomorphies

22
Q

What is a monophyletic group?

A

A common ancestor and all of its descendants

The only valid evolutionary group

23
Q

What is a clade?

A

A monophyletic group

24
Q

Why does monophyletic grouping make sense? 2 reasons.

A
  1. Defined by shared, derived characteristics
  2. Can’t randomly exclude descendants
25
Q

What is a paraphyletic group?

A

A group containing a common ancestor, but not all of its descendants

26
Q

What is homoplasy?

A

An evolutionarily invalid grouping by character states that appear the same in 2 taxa but have not evolved from a common ancestor

27
Q

Homoplasy is a result from what?

A

Convergent evolution

28
Q

What is convergent evolution?

A

Independent evolution of the same character state in multiple, separate lineages

29
Q

What is a polyphyletic group?

A

An evolutionarily invalid grouping: a group characterizes by 1 or more homoplasies

30
Q

What is parsimony?

A

“The simplest explanation is the best”

Best phylogenetic tree is the tree with the fewest evolutionary steps