Oct 14 Flashcards Preview

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Flashcards in Oct 14 Deck (33):
1

Who posited that life could be hierarchically organized or classified according to similarities?

Linneaus

2

TRUE/FALSE
Darwin showed that descent with modification could explain and support Linneaus’ hierarchical organization through similar features

TRUE
The evolutionary process of branching descent with modification generates nested hierarchies of similarities

3

What are the components of modern phylogenetics?

classification using similarities + branching descent

4

What is the study of patterns of branching relationships of populations that give rise to populations over evolutionary time

phylogenetics

5

What is the aim of phylogenetics?
a) discover shared ancestry btw organisms
b) identify history of descent between
populations characterized by shared features
c) all of the above

c) all of the above

6

What is used to construct phylogenies?

traits

7

Traits are used to infer...

patterns of ancestry
sequence and timing of events

8

TRUE/FALSE
Darwin inferred common ancestry and demonstrated its underlying mechanisms

FALSE
Darwin predicted the presence of heritable material but it was not proven until DNA was discovered

9

DNA sequence similarity should reflect patterns of common ancestry inferred from morphological traits and fossil evidence if...

descent with modification holds

10

What is a taxa?

related organisms (species, genera, phyla)

11

What does an interior node in a phylogenetic tree represent?

hypothetical common ancestor for connected taxa

12

What does a root in a phylogenetic tree represent?

convergence of all taxon relationships

13

What is polytomy and what does it represent?

>2 taxa emerge from a node
uncertainty about evolutionary relationships

14

What are sister taxa?

taxa derived from the same recent ancestor

15

What is an outgroup?

an early branching relative of the interest groups

16

___ is group of organisms with a
shared ancestor

clade

17

What is a monophyletic group?

includes the most recent common ancestor of a group of organisms, and all of its descendents

18

What is polyphyletic group?

does not include the recent common ancestor

19

What is a paraphyletic group?

includes the most recent common ancestor, but not all of its descendents

20

What is the difference btw a rooted tree and an unrooted tree?

Rooted trees indicate a common line of descent through time
Unrooted trees do not strictly illustrate evolutionary relationships

21

What is a phylogram?

evol. relationships and changes over time (branch lengths)
-longer branches = more changes

22

What is a chronogram?

relationships, changes calibrated to actual time

23

What type of tree shows only evolutionary relationship?

cladogram

24

(Short-lived/long-lived) organisms have more heritable changes?

Short-lived bc faster mutation rates

25

Which evolved more slowly, shrubs/trees or herbaceous plants? Why?

shrubs/trees bc fewer generations per year

26

What is the difference btw a homologous and analogous trait?

Homologous traits due to ancestral inheritance
Analogous traits are similar but not of ancestral origin

27

What is a homoplasy?

Analogous trait

28

What is divergent evolution? Give example

closely related organisms diverge ie. different colored mice

29

What is convergent evolution? Give example

similar traits arise in non-related organisms ie. light lizards and mice in desert

30

What is a synapomorphy?

derived trait that is shared by two or more taxa and inferred to have been present in their most recent common ancestor, whose own ancestor in turn is inferred to not possess the trait

31

What is symplesiomorphy?

ancestral state is not shared by closely related
species

32

What slow-evolving traits are good for drawing trees?

synapomorphies

33

What is parsimony?

fewest evolutionary changes to explain observed traits