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Biology 2 Lecture > Chapter 25 > Flashcards

Chapter 25 Flashcards

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1
Q

microevolution

A

evolution observed at the population level

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2
Q

macroevolution

A

evolution over a very long period of time

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3
Q

phylogeny

A

evolutionary history of a group of organisms

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4
Q

phylogenetic tree

A

simplified diagram of evolutionary history of group of organism

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5
Q

systematics

A

discipline of biology that characterizes and classifies relationships among organisms and builds tree of life

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6
Q

taxa

A

named group of organisms at any level of classification system

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7
Q

how do phylogenetic trees answer the question of taxonomy

A

help describe, name, and classify species

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8
Q

branch

A

line representing a species or other taxon through time

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9
Q

root

A

most ancestral branch in tree

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10
Q

tip

A

endpoint of branch
- represents living or extinct species

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11
Q

outgroup

A

taxon that diverged before taxa you are trying to classify

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12
Q

node

A

point within tree where branch splits into two or more branches
- represents the most recent common ancestor

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13
Q

polytomy

A

node that depicts ancestral branch dividing into three or more descendant branches

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14
Q

sister groups

A

two lineages that are each other’s closest relatives
- two descendants that split from same node and are each other’s closest relative

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15
Q

what does the number of nodes depends on

A

number of taxa that are included in a tree

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16
Q

trait

A

any heritable genetic, morphological, physiological, developmental, or behavioral characteristic that varies among taxa

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17
Q

what characters are used to build a phylogenetic tree

A
  • molecular characters (DNA)
  • morphological characters
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18
Q

data matrix

A

table the enables you to score character states of each taxon
- trait is (1)present or (2)absent

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19
Q

ancestral trait

A

character that existed in an ancestor

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20
Q

derived trait

A

modified form of ancestral trait
- found in descendant

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21
Q

how do derived traits originate

A

mutation
selection
genetic drift

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22
Q

synapomorphy

A

another name for shared derived traits in multiple taxa

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23
Q

monophyletic group

A

evolutionary unit that includes an ancestral species and all of its descendants

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24
Q

homology

Study These Flashcards
A

similarity due to common ancestor
- same source

25
homoplasy
occurred when traits evolved independently in two or more different lineages and are similar for reasons other than common ancestry - same form
26
parsimony
assumes that the most likely explanation or pattern is the one that requires the fewest steps - count number of character state changes required to produce each pattern, lowest number of these is best
27
evolutionary distance
more rapid evolutionary change may occur in some branches than others - look at average frequency of character state changes between individual pairs of taxa
28
maximum likelihood and Bayesian analysis
- mathematical models - popular with molecular data sets - precise estimates of evolutionary history
29
what is a common cause of homoplasy
convergent evolution
30
convergent evolution
independent evolution of similar traits in distantly related organisms due to adaptation to similar environments
31
fossils
pieces of physical evidence from an organism that lived in the past
32
what are the different types of fossils
intact compression cast permineralized trace
33
intact fossil
forms when decomposition does not occur and organic remains preserved intact
34
compression fossil
sediments accumulate on top of organism and become cemented into rocks
35
permineralized fossils
organisms decompose extremely slow and dissolved minerals gradually infiltrate interior of cells and harden
35
cast fossil
buried organism decomposes, leaving an empty cavity in sediments that fills with dissolved minerals and hardens to form a cast
36
trace fossil
sedimentation and mineralization preserve indirect evidence of an organisms in the environment
37
how do fossils form
organism must perish in an environment where they are buried rapidly and decomposed slowly
38
what types of organisms are most likely to form fossils based on habitat bias
ones that live in a location where sediments are actively being deposited
39
what types of organisms are most likely to form fossils based on taxonomic bias
- those with hard parts of the body (bones or shell)
40
what kind if fossils are much more common based on temporal bias
recent fossils compared to ancient fossils - older a fossil is, longer it has been exposed to destructive forces
41
what types of organisms leave fossils more often based on abundance bias
ones thar are abundant, widespread, and present on Earth for long periods of time
42
how is the Earth's history divided into
segments called eons, eras, periods, and epochs
43
what tool do researches use to identify times on the fossil record
radiometric dating
44
Anthropocene
reflect dramatic physical, chemical, and biological changes humans are causing on Earth
45
adaptive radiation
single lineage rapidly produces many descendant species with a range of adaptative forms
46
what are the three parts to adaptive radiation
monophyletic group speciated rapidly diversified ecologically into many niches
47
niche
range of conditions that a species can tolerate and the range of resources that it can use
48
what mechanisms can trigger adaptive radiations
extrinsic (external) intrinsic (within)
49
adaptative radiation of animals is called
Cambrian explosion - rapid diversification of animal body types and lineages
50
fauna
collection of animal species
51
what are the potential causes of the Cambrian explosion
higher oxygen levels rise of algae evolution of predation new niches gives rise to more new niches new genes, new bodies of water
52
mass extinction
rapid extinction of a large number of diverse species around the world
53
what is the opposite of a mass extinction
adaptive radiation
54
background extinction
refers to lower, average rate of extinction observed when mass extinction is not occurring
55
what is "The Big Five"
five spikes denoting a large number of extinctions within a short time
56
difference between background and mass extinctions
- background occur when normal environmental change, emerging disease, predation pressure, or competition reduces certain populations to 0 - mass result from extraordinary, sudden, and temporary changes in environment
57
what are extinctions often followed by
adaptive radiations due to ecological opportunity

Biology 2 Lecture (18 decks)

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