Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology 152 > Evolution > Flashcards

Evolution Flashcards

1
Q

Charles Darwin

A

Travelled around the world on the HMS Beagle and developed the first theory of evolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the three key ideas of evolution?

A

Common ancestry, populations evolve, natural selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What important observation did Darwin make while on the HMS Beagle?

A

Species (living and fossil) tend to live near their closest relatives because they descended from a common ancestor that lived in that area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T/F: common ancestry requires evolution

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How did Darwin believe evolution occurred?

A

A mutation within one subject of a population that was passed on through generations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Natural selection

A

Genetic variants that are better adapted will tend to increase in frequency in a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the three big ideas of evolution?

A

Common ancestry unites all life, populations evolve, natural selection provides direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the four types of evidence for common ancestry?

A

Geographic distributions, fossil record, unexpected similarities among living species, treelike patterns of variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Biogeography

A

Closely related species live near each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why is biogeography unlikely for separate ancestry?

A

It is very unlikely that hundreds of species of one animal would have ended up in only one fraction of the world rather than all over

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do fossils support common ancestry?

A

When they fit into ancestry trees based on geographics, morphology, and temporals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do fossils support common ancestry through morphology?

A

There are features present in the fossils that very closely resemble features seen in species present today

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How to fossils support common ancestry through temporals?

A

The order in which they received their traits makes sense in matters of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Transitional fossil

A

A fossil that shows some but not all the derived features of a living group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe “deep” similarity to the evidence of common ancestry

A

Organisms share structural features but it is especially compelling when those same features serve different functions among different species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Vestigial structure

A

Structure that is non-functional in one species but functional in another related species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the connection of “badly designed” structures to common ancestry

A

There are poorly designed structures that are shared among species that is only possible if they descended from the same ancestor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Speciation

A

The formation of a new/distinct species in the course of evolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does speciation occur?

A

Geographic isolation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Geographic isolation

A

Geographics separates part of a population so interbreeding can no longer occur, gene flow ends and differentiation occurs, differences accumulate until they reach a threshold to be considered a new species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Clade

A

An ancestral node and all of its descendants, all taxons and their CA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

T/F: all members of a clade share a more recent CA with each other than anyone outside the clade

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Topology

A

The branching pattern of a phylogenetic tree

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Relatedness

A

The recency of common ancestry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
T/F: relatedness refers to sharing of traits
False, refers to sharing of recent CA
26
T/F: a phylogenetic tree shows advancements
False, no species is more advanced than another (no goal to evolution, all equal)
27
Parsimony
Hypothesis in which history favors the path of fewest evolutionary changes as most likely being true
28
Convergence
“Same” character state could evolve independently in two different lineages
29
Reversal
A character state can evolve to resemble the state seen in an ancestor
30
Parsimony uninformative
Patterns in character traits that do not help choose the most parsimonious tree
31
Parsimony informative
Have at least two character states each present in at least two taxa
32
T/F: only genetic changes count as evolution
True, it implies a change in population gene frequency
33
What does it mean when a population has 50/50 gene frequency? (H-W assumptions)
There is no mutation, no emigration, the population is very large, mating is random, and there’s no difference in the success of alleles
34
What conditions allow evolution to occur?
Mutation, migration, when there is differences in success of alleles, mating is non-random, and the populations are finite
35
T/F: evolution by genetic drift depends on genetic variation and removes genetic variation
True
36
T/F: smaller populations lose variation faster
True, shown as large jumps in graph, shorter generations, and become genetically identical
37
Natural selection
Biased genetic drift that results in adaptations, increases frequency of one allele consistently
38
Fitness
Average reproductive output of individuals with a certain genotype
39
What does reproduction require?
Surviving, ***producing offspring, and finding a mate (unless asexual)
40
Explain evolution and relative fitness
Evolution only cares about alleles relative to one another— one allele assigned 1.0 while other value is determined relative to it
41
Genetic drift
Change in frequency of an allele due to random effects of limited population size
42
Directional allelic selection
Rapid fixation of a favored allele, removes variation faster than genetic drift w11 > w12 > w22 (or signs flipped)
43
When does directional selection overpower genetic drift?
Large populations, the favored allele begins at a high frequency
44
HW equilibrium equations
p^2 + 2pq + q^2 = 1 p+q=1
45
Balancing allelic selection
Alleles and low frequency have an advantage and tend to reach a stable, balanced state w11 < w12 < w22 Slow rate of fixation/loss
46
Disruptive allelic selection
Disfavor of the more rare allele and prevents evolution of potentially beneficial alleles generated by mutation w11 > w12 > w22 Heterozygotes have lowest fitness
47
How do complex traits evolve?
Directional selection acts over long periods of time causing mutant alleles at many loci to increase in frequency and go to fixation
48
Quantitative genetics
Model for how a phenotype responds to selection when the first trait is controlled by many alleles and many loci
49
How much of a trait can be acted on by selection?
Only variation that is due to loci with alternative alleles, NOT environmentally induced variation
50
Heritability
Measure of how much of the variation in a trait in a population is explained by genetics (assumes environment is not inherited)
51
What is the heritability value of trait variation that can only be explained by environment?
h^2= 0.0
52
What is the heritability value when trait variation is explained only by genetics?
h^2= 1.0
53
Formula for strength of selection
(Mean of reproducing individuals) - (mean of entire population)
54
Formula for response to selection
(Mean of offspring generation) - (mean of parent generation)
55
Formula for response to selection
r= (h^2)s Heritability x strength h=0 — no response to selection
56
Directional phenotype selection
One extreme is favored, mean frequency of the population moves, variance decreases
57
Stabilizing phenotype selection
Favors phenotypes near the mean, decreases variance, more narrow bell curve but same mean
58
Disruptive phenotype selection
Either extreme is favored, disfavors phenotypes near mean, increases variance
59
Allopatric speciation
Geographical separation results in a split in linage to form new species
60
How does sympatry speciation occur?
Through disruptive selection and assortative mating
61
Assortative mating
Individuals mate with preference to those similar to them
62
How do multi-part features arrive without planning ahead?
Exaptation= a trait arose for one reason, was maintained, and then became necessary for another function
63
How are exaptation traits explained by directional selection?
These traits reduce the ability to survive by making organisms more visible (only in males)
64
Sexual selection
Selection for improved mating success even at the expense of survival that is driven by female choice or male conflict
65
Runaway sexual selection
Feedback loop of: females prefer one trait, selection favors that trait, selection favors females with preference, which prefer the same one trait...etc ** why extreme phenotypes exist
66
Why does runaway selection occur mainly in polygamous species?
Males have high variance in reproductive success in which few have many offspring (had a trait that was preferred by females) ex: male bird spends weeks building nest to attract females
67
Altruistic trait
Organism reduces own fitness to increase the fitness of another - applies to the entire population - explained by directional selection
68
Group selection
Traits that improve the net success of a population are favored even if it is disadvantageous to some members of the population
69
When does group selection favors altruism?
When there are local groups that differ in frequency of altruistic vs selfish genotypes (groups with more altruism do better)
70
Individual selection
Alleles that improve individual fitness in a population will tend to increase in frequency
71
Describe LUCA
A complex prokaryotic cell that was a chemoautotroph
72
Chemoautotroph
Organism that uses redox chemistry to convert carbon dioxide into sugars
73
Define life
A self-supporting system of chemicals that can evolve adaptively
74
Hadean earth
Period of earth that contained lots of carbon and reducing gases (H2, NH3, H2S) but NO oxygen gas
75
How did organic molecules become organized into life?
Chemicals were passed on without genes or cells by sticking to surfaces to grow, spread, and adapt into cellular components
76
Surface metabolism theory
Chemical networks arose spontaneously on mineral surfaces through a reverse Krebs cycle
77
How did cells/genetics originate?
Mineral surfaces can appear/disappear/change as well as movement of auto catalytic systems to other surfaces to multiply
78
Characteristics of bacteria
Diverse metabolism, essential for nutrient cycling, and many symbiotic associations
79
Symbiosis
Interaction between two organisms living in close contact
80
Mutualism
The interaction is good for both organisms
81
Parasitism
The interaction is good for one but not the other
82
Characteristics of Archaea (except eukaryotes)
Can live in extreme environments, some mutualists but few parasites, metabolically diverse, similar to eukaryotes
83
Characteristics of oxygenic photosynthesis
Made possible by Cyanobacteria, oxygen is the electron donor and is oxidized, takes a lot of energy, and requires two photo systems
84
How did the oxygenic photosynthesis originate?
A photosystem I bacteria taking up the DNA of a photosystem II bacteria (or vice versa)
85
What are the consequences of oxygenic photosynthesis?
Oxygen accumulated in the atmosphere with iron to produce ozone, allowed for the origin of aerobic respiration
86
Characteristics of eukaryotes
Called are 10x larger than prokaryotes, endomembrane system, microbial top predators, many origins of multicellularity
87
Endosymbiotic theory of the endomembrane system
A proteobacterium was engulfed by a eukaryote (already had a nucleus)
88
Autogenous theory of endomembrane system
A genome formed a double membrane that split into two (mitochondria and a mass), the mass develops into a nucleus

Biology 152 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions