1
Q
gene flow
A
genetic exchange with another population via imigration/emigration
2
Q
gene flow inc/dec differences (from mutations, natural selection, genetic drift) between populations
A
decreases
3
Q
genetic drift
A
chance events that alter allele frequencies in a population
4
Q
genetic drift inc/dec genetic variation
A
decreases
5
Q
bottleneck effect
type of genetic drift
A
large reduction in population size causes reduced gene flow
example of genetic drift
6
Q
founder effect
A
new population established by a small number of indiivudals from a larger one; decreased genetic diversity = high frequencies of certain genetic traits/diseases in new population
example of genetic drift
7
Q
mutations
A
changes in nucleotide sequences of DNA that is passed down generations caused by mistakes in DNA replication/DNA damage caused by chemical mutagens, radiation, etc.
8
Q
? is the heritable source of all genetic variation
A
mutations
9
Q
natural selection
A
differential reproductive success causing inheritable traits, and therefore, evolution
10
Q
what creates adaptations?
A
natural selection
11
Q
stabilizing natural selection
A
favors middle phenotype
12
Q
directional natural selection
A
favors an extreme phenotype
13
Q
disruptive natural selection
A
favors both extremes
14
Q
evidence for natural selection
A
- biogeography
- comparitive morphology
- geological discoveries
15
Q
biogeographic evidence for natural selection
A
- similar species often live in the same geographic region
- share similar traits
- some different species that live in different regions share similar forms
16
Q
comparitive morphology as evidence for natural selection
A
- homologous structures
- vestigial structures
17
Q
vestigial structures
A
remnants of a body part that have lost their original function over the course of evolution, but remain as a leftover from an ancestor
18
Q
geological discoveries as evidence for natural selection
A
- fossils are related to known species
- deep layers of the earth contain more simple fossils than shallower layers
19
Q
sexual selection
A
choosing a mate since they have advantages over another mate
20
Q
runaway sexual selection
A
a trait in males becomes exaggerated due to female mate choice, even if the trait is costly for survival
21
Q
asymmetric investment in offspring
A
drives sexual selection; females invest directly inn offspring while males invest in mating opportunities since males can produce sperm at less of a cost than females can produce eggs
22
Q
intersexual selection
A
includes female and male choice
23
Q
female choice
A
females choose a male mate; leads to sexual dimorphism
24
Q
sexual dimorphism
A
diferences in phenotypic appearance between males and females within the same species; caused by female choice
25
how is sexual dimorphism caused by female choice?
females tend to be the more selective sex, favoring males with exaggerated traits that are linked to better fitness, such as bright colors or large size
26
types of female chocie
* non-adaptive
* directly adaptive
* indirectly adaptive
27
non-adaptive female choice
female mating preferences that do not appear to provide a survival or reproductive benefit, and may even be detrimental to the female or her offspring (ex: sensory bias, species recognition)
28
directly adaptive female choice
selecting a mate for immediate benefits to the female, such as resources or improved survival; phenotypic traits in male mate infer higher fitness in offspring
29
indirectly adaptive female choice
females select males based on genetic benefits that will be passed to their offspring, rather than for immediate benefits to the female herself
30
intrasexual selection
sexual selection within the sex (males compete to mate with as many females as possible, causing males to be competitive); also leads to sexual dimorphism
31
precopulatory male-male competition
physical fighting, territory defense, etc
32
postcopulatory male-male competition
competition between sperm from different males
33
costs of sexual reproduction
* slower population growth
* energetically costly
34
adaptations
traits acquired through natural selction for an individual to survive and reproduce in their environment
35
benefits of sexual reproduction
* increased genetic variability
* provides greater disease resistance
* greater resistance to environmental changes
36
what limits male reproductive success?
number of available female to mate with
37
allopatric speciation
geographic barrier divides population or part of population crosses barrier and "founds" new population, causing gene flow to be cut off = microevolution = differentiation
38
Dobzhansky-Muller model
subdivie population evolves independently; combination of these new alleles from each population is incompatible, leading to reduced hybrid offspring fitness or sterility
39
sympatric speciation
species arise from a connected population
40
sympatric speciation mostly happens in ?
plants
41
causes of sympatric speciation
* behavioral changes
* polyploidy (extra chromosomes cause by mistakes during cell division create viable, but genetically isolated offspring)
42
what does polyploidy cause to happen in plants?
self fertilization
43
autoploidy
chromosome duplication in a single species
44
alloploidy
combining chromosomes of two different species
45
convergent evlotion
species have different ancestors, making them genetically different even though they look more similar over time; create analagous structures
46
analagous structures
arise due to convergent evolution
47
divergent evolution
species share a common ancestor, making them closely related even though they look more different over time; create homologous structures
48
homologous structures
similarities due to shared common ancestor; arise due to divergent evolution
49
what kind of evolution creates homologous structures?
divergent evolution
50
q in HWE
frequency of the recessive allele (# of allele copies/sum of all alleles)
51
p in HWE
frequency of the dominant allele (# of allele copies/sum of all alleles)
52
2pq in HWE
frequency of heterozygous individuals
53
p^2 in HWE
frequency of homozygous dominant individuals
54
assumptions of HWE
* no mutation
* random mating
* no gene flow
* very large population size
* no natural selection
55
Darwin
* any species is capable of increasing its population size exponentially, but this rarely happens since resources are limited
* proposed term of natural selection
56
Wallance
* developed the theory of evolution by natural selection
* reproductive isolation and speciation
57
Kimura's theory of evolution
* most genetic variation arises through the accumulation of neutral mutations (synonymous mutations/mutations to noncoding regions)
* neutral mutations must accumulate thry genetic drift since they aren't under selection
* rate of fixation of new neutral mutations is independent of population size and equals mutation rate
58
Linnaeus
* studied taxonomy
* came up with binomial nomenclature (genus species)
* came up with hierarchical classification (domain, kingdom, phylum, class, order, family, genus, species)
59
hierarchical classification
domain
kingdom
phylum
class
order
family
genus
species
60
Margulis
proposed endosymbiotic theory
61
Mendel
explaining the mechanism of inheritance, demonstrating that traits are passed on as discrete units (genes), not blended
62
biological speciation concept
the evolutionary process by which new and distinct species are formed from an ancestral species due to reproductive isolation
63
neoteny
the evolutionary process where an organism retains juvenile traits into adulthood; form of heterochrony
64
homoplasty
evolution of a trit that is shared by unrelated species because it arose independently vs from a common ancestor due to the unrelated species experiencing similar environmental pressures (convergent evolution)
65
what kind of evolution creates homoplasties?
convergent
66
heterochrony
an evolutionary change in the timing, rate, or duration of developmental events, leading to differences in an organism's size, shape, or other features compared to its ancestors
67
synonymous substitution/silent mutation
doesn't affect protein structure since different codon still codes for the same amino acid
68
nonsynonymous substitution/missense mutation
usually deleterious; change in codon codes for different amino acid = change in protein structure
69
evolution
descent of modern organisms with modifications from pre-existing life forms
70
components ofx evolution
* natural selection
* sexual selection
* gene flow
* genetic drift
* migration
71
evolution occurs on the ____?____ level
population
72
parthenogens
a form of asexual reproduction where an embryo develops from an unfertilized egg; causes exponential population growth
73
microevolution
changes in genotype/allele frequencies (meaning change in gene pool) of a population
74
macroevolution
changes in phenotype
75
Darwin's theory of pagenesis
incorrect explanation of heritable units that involves gemmules (body sheds tiny particles that are delivered to reproductive organs and passed to offspring via gametes) allow for heritability
76
Mendel's theory of heredity
parents pass discrete, heritable factors to offspring that are responsible for inherited traits via genes
77
natural selection happens on the ? level
individual
78
Aristotle's homunculus
sperm contained a zygote and females are essentially just incubators
79
causes of microevolution
* nonrandom mating
* gene flow (imigration/emigration)
* genetic drift
* natural slection
* mutations
80
fitness
contributions an individual makes to the gene pool of the next generation relative to the contribution of others
## Footnote
aka ability to survive and reproduce
81
genome
an organism's gene set + noncoding DNA (regulatory sequence and structural elements)
82
what creates variation in genome size?
differences in the amount of noncoding DNA
83
what causes the greatest rate of substitution (in mutations)?
greatest rate of substitution when changes have little effect on protein structure
psudeogenes > synonymous substitution > nonsynonymous substitution
84
rate of nonsynonymous substitution
dN = (# of nonsynonomous substitutions/# of all possible nonsynoymous substitutions)
85
rate of synonymous substitution
dS = (# of synonomous substitutions/# of all possible synoymous substitutions)
86
dN/dS < 1
purifying selection (eliminates harmful genetic mutations, or alleles, from a population)
87
dN/dS = 1
null hypothesis
88
dN/dS > 1
Darwinian selection (promotes spread of beneficial alleles); true for most codons
89
# >
molecular clock
rate of neutral DNA substitutions over time can be used to calculate evolutionary time scales
90
divergance rate
* the speed at which related populations or species develop distinct traits
* D/T
* D = % of base differences in DNA sequences of two closely related species
independently estimated time (based on fossils)
91
means of determining fossil records
* fossil records (radiometric/carbon dating, half-life)
* morphological dating (homologous/analagous)
* molecular clock
92
taxon
endpoints in phylogenetic trees
93
clade/monophyletic group
a group of organisms believed to have evolved from a common ancestor
94
sister taxa
two groups of organisms that are each other's closest relatives, sharing an immediate common ancestor from which they both diverged (two branches stemming from the same point on a phylogenetic tree and are part of the same monophyletic group/clade)
95
parsimony
simplest hypothesis capable of explaining the pattern (aka tree with fewest # of shared/derived traits)
96
outgroup
lonley taxon
97
paraphyletic evolution
group of orgaisms containing a common ancestor and some, but not all, descendants
98
polyphyletic evolution
group of organisms classified together based on shared traits that evolve independently (aka don't share a common ancestor); occurs because of convergent evolution
99
monophyletic evolution
group of organisms that inclues a single common ancestor an ALL descenants (only appropriate taxonomix unit since it correctly reflects evolutionary history)
100
speciation
barrier to gene flow -> genetic differentiation -> reproductive isolation
101
prezygotic reproductive barriers
* temporal isolation
* gamateic isolation (sperm and egg don't fuse)
* habitat isolation
* behavioral isolation
* mechanical isolation (incompatible sex organs)
102
postzygotic reproductive barriers
* reduced hybrid survivalship
* reduced hybrid fertility
103
what controls the tempo of speciation?
* rates of mutation
* rates of speciation (depening on competition, habitat availability, generation time)
* rates of environmental changes
104
# tempo of speciation
gradualistic model
slow divergence of isolated populations (looks like a v shape where population gets wider/grows as time goes on)
105
punctuated equilibrium
long periods of stasis (stagnation) followed by sudden episodes of speciation
106
adaptive radiation
relatively rapid evolution of many new, diverse speicies from a common ancestor under new environmental conditions
## Footnote
ex: Darwin's finches
107
coevolution
mutual evolutionary influence between two species occuring in the same environment
108
# dates
adaptive radiation of primates
65 million years ago
109
# dates
when mammals arose
175 million years ago
110
# dates
when great apes (hominoids) arose
25 million years ago
111
# dates
when hominids arose
5 million years ago
112
# dates
when homosapiens arose
200,000 years ago
## Footnote
have smaller teeth/jaw/facial bones, larger volume brain cases, and symbolic thought compared to homo erectus
113
Aristotle's abiogenesis (spontaneous generation)
.
the original evolution of life or living organisms from inorganic or inanimate substances
114
biogenesis (primoridial soup)
the synthesis of substances by living organisms
115
Darwin's ideas of biogenesis
protein compounds chemically form and undergo more complex changes in "warm little ponds with ammonia, salt, ligt, heat, electricity"
116
J.B.S. Haldane's idea of biogenesis
Earth's pre-biotic oceans forme a "hot diluted soup" in which organic compounds could have formed
117
Miller-Urey experiment for abiogenesis
create an atmosphere (H2O, CH4, NH3, H2) and exposed it to lightning (sparks), forming 22 amino acids
118
4 step biogenesis hypothesis
1. abiotic synthesis of small organic compouns (amino acids, nucleotides)
2. molecules combine, forming polymers/macromolecules (proteins and nucleic acids)
3. molecules packed into membranes = formation of protobionics (cell-like structures that form spontaneously, contain membranes, differ in interior/exterior environments, and capable of simple replcation and metabolism)
4. self replication beginning with RNA
119
# dates
formation of earth
4.5 billion years ago
120
# dates
first life on earth based on fossil records
3.5 billion years ago
121
# dates
first eukaryotes
2.2 billion years ago
122
# dates
first multicellular eukaryotes
1.2 billion years ago
123
# dates
cambrian explosion (period of rapid diversification)
535-525 million years ago
124
# dates
colonization of land by fungi, plants, animals
500 million years ago
125
Oxygen revolution
most O2 originated from photosynthetic bacteria
126
what led to the arrival of eukaryotes
the oxygen revolution
127
theory of endosymbiosis
mitochondria and chloroplasts were formerly small prokaryotes living in a larger host cell as endosynombionts (organisms that live within other organisms)
128
# f
evidence for endosymbiosis
* mitochonria and chloroplast have inner memrabne structures/functions like prokaryotes
* cell division is similar to some prokaryotes
* chloroplasts/mitochondria transcribe their own DNA (have ribosomes)
* organelles' ribosomes are more similar to prokaryotic ribosomes than eukaryotic ribosomes
BSC2010
flashcards
Decks in class (10)
# Cards
-
Unit 1 Lecture 1 Chemistry and Energy32
-
Unit 1 Lecture 2 Chemistry and Energy22
-
Unit 1 Lecture 03 Lipids23
-
Unit 1 Lecture 3 Carbohydrates18
-
Unit 1 Lecture 4 Nucleic Acid38
-
Unit 1 Lecture 4 Proteins29
-
Amino Acids27
-
Unit 1 Lecture 5 Enzymes20
-
Unit 1 Lecture 6 Plasma membrane18
-
Unit 3 Evolution128
