T4 - Systematics and Phylogeny Flashcards

1
Q

Systematics

A

The theory and practice of classifying organisms based on phylogeny

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2
Q

Phylogeny

A

the current hypothesis for the evolutionary history of a species or group of related species

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3
Q

Phylogenetic trees

A

Show the hypotheses of the evolutionary relationships between organisms through evolutionary descent and common ancestors

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4
Q

What are the two ways we can infer phylogeny?

A
  1. morphological data
  2. molecular data
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5
Q

morphological data

A

similarities between anatomical features

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6
Q

molecular data

A

similarities in molecular structures (DNA, RNA, protein)

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7
Q

Speciation

A

the divergence of two species from a common ancestor

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8
Q

sister taxa

A

two descendants from the same node/common ancestor

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9
Q

Basal Taxon

A

species that diverges early in the evolutionary history of a group, closer to common ancestor

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10
Q

Clade

A

a piece of a phylogeny with an ancestor and al its descendants; forms a nested hierarchy

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11
Q
A
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11
Q

Cladograms

A

phylogenetic trees based oonly on evolutionary relationships

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12
Q

Phylograms

A

phylogenetic trees based on evolutionary patterns AND chronological time of evolutionary change through line lengths

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13
Q

Polytomies

A

a part of a phylogeny that speciates into 3 descendants

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14
Q

2 causes of phylogenetic polytomies

A
  1. Lack of knowledge
  2. rapid speciatione.g. maybe quick displacement of species
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15
Q

Name 1 similarity about groups and 1 general difference between taxonomy and systematics.

A

Similarity: taxonomic rank = clades

Difference: the criteria used for grouping (similarity/difference vs. phylogeny)

16
Q

Homology/homologous traits

A

similarity in shared ancestry between two species

17
Q

Analogy/Analgous traits

A

similarities between species due to convergent evolution

18
Q

Convergent evolution

A

independent evolution of similar traits in different lineages

19
Q

Which is used in phylogenetic trees? Homologous or analogous traits?

A

Homologous ONLY

20
Q

Characters

A

anatomical, physiological, or molecular features of organisms

21
Q

Ingroup vs. Outgroup

A

Ingroup: group of taxa whose evolutionary relationships you want to compare/determin

Outgroup: usually used as a reference point for making phylogenetic trees (basal taxon), diverged from ingroup at an earlier time

22
Q

Cladistics

A

A method of inferring phylogeny from homologous characters

23
Q

Monophyletic

A

a grouping that consists of only the ancestor and its descendants; clade

24
Paraphyletic
A group that consists of an ancestral taxon but not all of its descendants
25
Polyphetic
A group that includes distantly-related taxa but not the common ancestor
26
Three causes of polyphyletic grouping
1. incorrect taxonomic classification 2. group is missing common ancestor 3. more than one common ancestor
27
Shared, derived character | AKA *synamorphy*
shared by 2+ taxa and most recent common ancestor, but NOT in the ancestor preceeding the clade
28
shared, ancestral character | AKA *symplesiomorphy*
shared by 2+ taxa AND taxa in an earlier clade
29
Apply Occam's razor in phylogeny
the tree with the least number of derived character changes is the most probable explanation for evolution
30
T/F: A phylogenetic tree is defined as 'factual" after 10 years without changes.
FALSE. The phylogenetic tree is always a hypothesis, and can always be proven wrong.
31