Lecture 12 - Phylogenetic Systematics Flashcards Preview

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Flashcards in Lecture 12 - Phylogenetic Systematics Deck (37):
1

What is phylogeny?

the evolutionary history of a species or groups of related species

2

What is taxonomy?

the science of naming and classifying organisms

3

What is systematics?

scientific system for classifying organsims

4

What are phylogenetic systematics?

classification of organisms by their order of branching on an evolutionary tree

5

Who developed old-school taxonomy?

Carolus Linnaeus

6

What are the two parts for scientific naming?

1. binomial nomenclature
2. hierarchical classification system

7

What has been added to the two part naming system?

Domain

8

What are the 7 levels of the hierarchical classification system?

(domain)
kingdom
phylum
class
order
family
genus
species
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9

Why have old-school Linnaean categories been criticized?

do not always form monophyletic groups

10

The class Reptilia is _______

paraphyletic

11

Invertebrates are ____

paraphyletic

12

Homeotherms are ________

polyphyletic

13

What is PhyloCode?

-proposed classification system

14

How does PhyloCode work?

-only monophyletic groups would be recognized
-most species names would remain unchanged
-use traditional taxonomic ranks

15

What is a node?

where the lineages diverge

16

What are sister taxa?

-most closely related groups
-groups of organisms that share an immediate common ancestor

17

What is the basal taxon?

one that branches off the earliest

18

What is polytomy?

an unresolved point of divergence

19

What are branches rotated around?

nodes

20

Phylogenies are inferred form ______ not _________

homologous characters not analogous characters

21

What are homologous characters?

common ancestors

22

What are analogous characters?

similar selective environments

23

What are homoplasies?

analogous structures or molecular sequences that evolved interdependenty

24

What is cladistics?

one approach to reconstructing phylogeny

25

Cladistics groups species into ______

clades

26

What are clades?

ancestor and all its descendents

27

What does cladistics focus on?

shared, derived characters

28

What principles does cladistics use?

1. parsimony
2. maximum likelihood

29

What is outgroup comparison?

distinguishes between ancestral and derived characters

30

What is an outgroup?

species/group from an evolutionary lineage that is known to have diverged before the lineage that includes the species we are studying

31

What happens in maximum parsimony?

the best tree requires the fewest changes

32

What is maximum likelihood?

alternative approach to reconstructing phylogeny

33

What happens in maximum likelihood?

the best tree is the tree with the highest likelihood given certain rules about how DNA changes over time
-more computationally intensive

34

What is a monophyletic group?

a common ancestor and all its descendents

35

What is a paraphyletic group?

a common ancestor and some of its descendants

36

What is a polyphyletic group?

a common ancestor is not present, but some descendants are

37

What is an example of real-world parsimony?

four chambered hearts in birds/mammals