Lecture Notes- Darwin and other big ideas Flashcards
1
Q
What is evolution?
A
change in genetic composition of populations over time
2
Q
Change in genetic composition of populations over time
A
Evolution
3
Q
Evolutionary change is observed in (blank)
A
Lab experiments, natural populations, and fossil record
4
Q
Genetic changes drive (blank)
A
origin and extinction of species and the diversification of life
5
Q
What is evolutionary theory?
A
Understanding of the mechanisms of evolutionary change
6
Q
Ways to apply evolutionary theory:
A
- understanding and treating diseases
- understanding the diversification of life and how species interact
- developing better agricultural crops and industrial processes
- predictions about bio world
7
Q
What supports the factual basis of evolution?
A
a vast array of geological, morphological, and molecular data
8
Q
What was Charles Darwin on for 5 years?
A
HMS Beagle
9
Q
study of organisms in environment
A
natural history
10
Q
Darwin’s Galapagos islands observations
A
species were similar to, but not the same as, species on the mainland of South America and that species varied island to island
11
Q
After observing the Galapagos islands, what were Darwins initial thoughts?
A
species reached islands form mainland but underwent different changes on different islands
12
Q
3 tenants of Darwin’s evolutionary theory:
A
- species change over time
- Divergent species share a common ancestor, and species have diverged gradually over time (descent with modification)
- mechanism produces change is natural selection
13
Q
Natural selection
A
the differential survival and reproduction of individuals based on variation in their traits
14
Q
What did Darwin publish? When?
A
“Origin of Species”- 1859
15
Q
Origin of Species
A
-provided EXHAUSTIVE evidence from many fields supporting both the premise of evolution itself and the role of natural selection as a mechanism of evolution
16
Q
Genetic variation contributes to (blank)
A
phenotypic variation
17
Q
In order for a population to evolve, members must possess (blank)
A
heritable genetic variation
18
Q
different forms of genes
A
alleles
19
Q
alleles exist at
A
locus
20
Q
sum of all copies of all alleles at all loci in a population
A
gene pool
21
Q
How do scientists date ancient events?
A
geological time scale
22
Q
Mechanisms of evolution
A
- mutation
- gene flow
- genetic drift
- nonrandom mating
23
Q
mutation adds (blank) to the gene pool
A
new alleles
24
Q
gene pool
A
all genes in population that make up genotype
25
proportion of an allele in the gene pool
allele frequency
26
proportion of each geneotype in the population
genotype frequency
27
calculation of allele and genotype frequencies is used to measure
evolutionary change
28
purposeful selection of specific phenotypes by humans
artificial selection
29
example of artificial selection
wild mustard plant
30
Darwin observed what in domesticated plants and animals, specifically what animal?
artificial selection-pigeon
31
artificial selection reveals (blank)
genetic variation
32
natural selection is also known as
survival of the fittest
33
trait that increases the chance that a given individual will survive and reproduce, increasing the frequency of the trait in the next generation
adaptation
34
aquisition of trait that allows for better survival and reproduction in environment
adaptation
35
natural selection removes
deleterious mutations
36
selection for beneficial changes
positive selection
37
selection against deleterious changes
purifying selection
38
result of the migration of individuals and movement of gametes between populations
gene flow
39
movement of one population group into another
gene flow
40
example of gene flow
new genes into gene pool (pop)
| humans expanded their range into range of Neanderthals
41
results from random changes in allele frequencies
genetic drift
42
harmful alleles may increase in (blank) and rare advantageous alleles may be (blank)
alleles, lost
43
in large populations, genetic drift can influence frequencies of alleles that (blank)
do not affect survival and reproduction
44
in small populations, genetic drift can be
significant
45
population bottleneck
survival by a few
46
environmental conditions result in survival of only a few individuals
population bottleneck
47
genetic drift can reduce (blank) in population
genetic variation
48
population bottleneck example
hunting and habitat destruction leads to decrease in prairie chicken
49
colonizing population is unlikely to have all the alleles present in whole population
founder effect
50
occurs when individuals choose mates with particular phenotypes
nonrandom mating
51
plant example of nonrandom mating
self-fertilization
52
if individuals choose the same genotype as themselves, (blank) will increase
homozygote frequencies
53
form of nonrandom mating that favors traits that increase in the chances of reproduction (not survival)
sexual selection
54
example of sexual selection
traits such as bright colors or long tails may improve ability to compete for mates or to be more attractive to the opposite sex
55
Sexual selection favors reproduction, but can (blank)
harm survival
56
Sexual selection may favor traits that enhance an individual's chances of reproduction but (blank)
reduce its chances of survival
57
Example of sexual selection improving reproduction
frogs call being signal of survival
58
mutation
change in nucleotide sequence that effects allele
59
gene flow
gene from 1 pop to another
60
genetic drift
random changes in allele within population
61
nonrandom mating
having preference and driven by sexual selection
62
5 mechanisms of evolution
```
natural selection
mutation
gene flow
genetic drift
nonrandom mating
```
63
Evolutionary change can be measured by (blank)
allele and genotype frequencies
64
allele frequency equation
p = number of copies of the allele in the population / total number of copies of all alleles in population
65
If there is only one allele at a locus, its frequency = (blank) and the population is monomorphic at that locus meaning the allele is (blank)
1
| fixed
66
p + q =
1
67
q =
1-p
68
allele frequencies at each locus and genotype frequencies
genetic structure
69
measure the amount of genetic variation in a population
allele frequencies
70
show how a population's genetic variation is distributed among its members
genotype frequencies
71
How genetic structure of a population changes over time is (blank)
a measure of evolutionary change
72
If (blank) occurs, the genetic structure of a population does not change over time
certain conditions are met
73
Hardy-Weinberg equilibrium
describes a model situation in which allele frequencies do not change
74
Genotype frequencies can be predicted from (blank)
allele frequencies
75
Conditions that must be met for Hardy-Weinberg equilibrium
- no mutation
- no selection among genotypes
- no gene flow
- population size is infinite (no genetic drift)
- mating is random
76
If conditions of Hardy-Weiberg occur...
-allele frequencies remain constant
-after one generation, genotype frequencies occur in these proportions
AA, Aa, aa
p2 +2pq +q2 = 1
77
Deviations from Hardy-Weinberg show (blank)
occurrences of evolution
78
What is Hardy-Weinberg useful for?
-predicting genotype frequencies from allele frequencies
79
Why is Hardy-Weinberg important?
patterns of deviation from the model help identify mechanisms of evolutionary change
80
Natural selection acts directly on (blank)
phenotypes
81
Reproductive contribution of a phenotype to subsequent generations relative to other phenotypes is called
fitness
82
(blank) of different phenotypes leads to change in allele frequencies
only changes in relative success
83
fitness of a phenotype is determined by he (blank) of survival and reproduction of individuals with that phenotype
relative rates
84
Quantitative traits show (blank)
continuous variation
85
many traits are influenced by alleles at more than one locus and show (blank) variation
quantitative
86
Distribution of body size in a population is likely to resemble a (blank)
bell-shaped curve
87
Natural selection can act on traits with quantitative variation in 3 ways:
- Stabilizing selection
- Directional selection
- Disruptive selection
88
Stabilizing selection
preserves average phenotype
89
Directional selection
favors individuals that vary in one direction
90
Disruptive selection
favors individuals that vary in both directions from the mean
91
Stabilizing selection- graph
reduces variation, does not change mean
92
Directional selection- graph
individuals at one extreme; more successful
| increase in allele frequencies for favored phenotype
93
Example of stabilizing selection
birth weight
94
Example of directional selection
Texas longhorn cattle
95
Example of disruptive selection
black bellied seed cracker birds (bill size)
96
Disruptive selection- graph
individuals at either extreme more successful than average ones; increases variation in population
-not centered on mean
97
an allele that does not affect fitness
neutral allele
98
which alleles tend to accumulate in a population?
neutral alleles
99
Molecular techniques
identify neutral alleles
| study divergence of pops and species
100
Sexual recombination amplifies the (blank)
number of possible genotypes
101
Sexual reproduction results in (blank) through the combination of gametes, crossing over, and independent assortment
new combinations of genes
102
Sexual recombination produces (blank) that increases (blank)
genetic variety
| evolutionary potential
103
disadvantages of sexual reproduction
- recombination can break up adaptive gene combinations
- rate at which females pass genes to offspring is reduced
- dividing offspring into genders reduces overall reproductive rate
104
Key advantages of sexual reproduction
- facilitates repair of damaged DNA
- permits elimination of deleterious mutations
- Sexual recombination generates new combinations of alleles on which natural selection can act
105
a polymorphism can be maintained when fitness depends on its frequency in the population
frequency-dependent selection
106
example of frequency-dependent morphism
fish with right vs let leaning jaws eating scales off predators
107
Environmental variation helps (blank)
preserve genetic variation
108
Example of environmental variation preserving genetic variation
butterflies live in environment with temp extremes; pop polymorphic for enzyme that influences flight at different temperatures; heterozygotes favoredbecause they can fly over a larger temp range
109
enzyme that influences flight at different temperatures
phosphoglucose isomerase
110
Genetic variation within species is maintained in (blank)
geographically distinct populations
111
Plant species may vary geographically in the chemicals they synthesize for defense- example
populations of white clover produce cyanide and therefore are found in areas that are not frozen often
Europe- clinical variation
112
Difficulties of theory of evolution
- absense or rarity of transnational varieties
- organs o extreme perfection (eyes)
- instinct
113
Evidence for a common ancestor
- morphology
- embryology
- rudimentary organs
114
Morphology
homology exists across life
115
Embrology
similarity between embryos early in development
