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Exam 3 Flashcards

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1
Q

evolution

A

acts on genetic variation in a population

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2
Q

types of variation

A

p - phenotypic
g - genotypic
e - environmental
Vp= Vg + Ve

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3
Q

Sources of genetic variation

A

mutation, altering gene number/position, sexual reproduction

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4
Q

Mutation (form new alleles)

A

new allele or gene expression, new protein expressed, or suppressed
- animal & plant mutation rate: 1/100,000 genes per generation

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5
Q

Long term evolution experiment

A

LTEE - Dr. Lenski, demonstrated evolution of a novel gene

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6
Q

Altering gene number/position (chromosomal changes)

A

gene duplication

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7
Q

sexual reproduction

A
  • genetic recombination crossing over (sperm and egg meiosis)
  • independent assortment of chromosomes
  • fertilization
    2 copies, creating new/novel genome
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8
Q

population genetics

A

branch of genetics that studies the allele frequencies of populations
Ff FF ff

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9
Q

Gene pool

A

all genetics in a population

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10
Q

hardy-weinberg equilibrium

A

no change in allele frequencies through time
*population is not evolving
when frequencies of not change
p+q=1

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11
Q

Conditions for Hardy-Weinberg Equilibrium

A
  1. No mutations
  2. Random Mating (selection)
  3. No natural selection (selection)
  4. Extremely large population size (genetic drift)
  5. No gene flow (gene flow)
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12
Q

Consequence if the HWE condition does not hold: no mutations occur

A

gene pool is modified if mutations occur or if entire genes are deleted or duplicated

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13
Q

Consequence if the HWE condition does not hold: Random mating

A

if individuals mate within a subset of the population, such as near neighbors or close relatives (inbreeding), random mixing of gametes does not occur and genotype frequencies change

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14
Q

Consequence if the HWE condition does not hold: No natural selection

A

Allele frequencies change when individuals with different genotypes show consistent differences in their survival or reproductive success

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15
Q

Consequence if the HWE condition does not hold: Extremely large population size

A

In small populations, allele frequencies fluctuate by chance over time (genetic drift)

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16
Q

Consequence if the HWE condition does not hold: No Gene Flow

A

By my moving alleles into or out of populations, gene flow can alter allele frequencies

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17
Q
  1. Natural Selection - adaptive evolution
A

Change in frequency of beneficial trait.

A trait that can evolve by natural selection must be:
- heritable
-variable
-affective fitness
Components: sexual selection, balancing selection

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18
Q

relative fitness

A

contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals

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19
Q

Mechanisms of Evolution

A
  1. Natural Selection
  2. Genetic Drift
  3. Gene Flow
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20
Q

applications of HWE

A

give geneticists a way to calculate the frequency of alleles and genotypes in a population

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21
Q

sexual selection

A

intrasexual selection: members of the same sex are selection agents (males competing for dominance)
intersexual selection: members of the opposite sex are selection agents (specific traits in different sex)

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22
Q

balancing selection

A

mentioning two more phenotypic forms in a population
- frequency-dependent selection
- heterozygous advantage
ex. sickle cell anemia (recessive) and malaria (heterozygotes are more likely to survive malaria)

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23
Q
  1. Genetic Drift
A

random fluctuations in allele frequencies due to chance
- can cause harmful alleles to become FIXED (all individuals have same allele)

Increase risk of extinction
- no genetic diversity
- recessive and dominant

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24
Q

Genetic drift - founder effect

A

movement of random individuals to a new location - their alleles become most common

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25
Genetic drift - bottleneck effect
survivor effort, disaster occurs and only few survive - small population size - changes allele frequencies - loss of less common alleles Random chance, death or small population
26
3. Gene flow
- transfer of alleles in/out of a population - migration caused by migration/movement* of individuals
27
What is a species?
a group of organisms that consist of similar individuals capable of interbreeding or exchanging genes among themselves
28
Species definitions
- biological species concept - morphological species concept - phylogenetic species concept - ecological species concept
29
Biological species concept
-Groups of actually or potentially interbreed natural populations - reproductive isolation from other species
30
Reproductive isolation
1. pre zygotic barriers 2. post zygotic barriers
31
Prezygotic barriers
-habitat isolation -temporal isolation -behavioral isolation -mechanical isolation -gametic isolation
32
Postzygotic barriers
-reduced hybrid viability -reduced hybrid fertility -hybrid breakdown
33
Prezygotic barriers before mating
habitat isolation - different location temporal isolation - time (reproductive cycles) behavioral isolation - different sexual selection, behavior ex. bird calls
34
Prezygotic barriers after mating
mechanical isolation - mechanically imposible to get sperm to egg gametic isolation - egg only accepts sperm from specific species
35
post zygotic barriers after fertilization
reduced hybrid viability - low fitness after embryo is born, can't reproduce, function properly reduced hybrid fertility - can't have offspring (chromosomal) hybrid breakdown - hybrid is okay, 1st gen okay, 2nd->3rd, lower fitness and cannot have offspring
36
Problems with BSC (biological concept of species)
1. asexual species 2. extinction, dead of difficult species *can't look at fossils and how they reproduced 3. hybridization -> viable, fertile offspring, one offspring towards another HYBRID VIGOR (LIGER) 4. Ring Species
37
morphological species concept
Physical appearance similarities (fossil structure, different structures in species)
38
problem with morphological species concept (msc)
1. Reproductive isolation
39
phylogenetic species concept
DNA similarities - using DNA to access DNA similarities in individuals - finding human genome
40
problems with phylogenetic species concept (psc)
1. expensive (changing) 2. No DNA (can't look at fossils) 3. Not field applicable (only lab technique) Hybridization more common, difficulty for PSC
41
Ecological species concept
broad concept -occupy different niches -may occasionally interbreed -interested in species role in environment
42
hybridization
mix between two different species
43
species conservation
endangered species act (1973) - protected bald eagles - successful with wolves
44
Speciation steps
1. reproductive isolation (barrier between both) 2. evolution (new species) 3. evolution (new species thrives and overcomes the old)
45
modes of speciation
Allopatric and sympatric
46
allopatric speciation
physical separation
47
sympatric speciation
same space, barriers between but organisms can still get through barrier
48
factors promoting speciation
- Physical barriers/seperation, habitat differentiation (ex. east vs west of ocean) - Polyploidy (one species w/ 12 chromosomes, one species w/ 24 chromosomes = can't reproduce together) ex. plants - Sexual selection (water depth)
49
Speciation rates
slow - gradual model rapid - punctuated equilibrium
50
Origins of early life
* Abiotic synthesis of small organic molecules (e.g., amino acids, nitrogenous bases) * Small molecules form macromolecules (e.g., nucleic acids and proteins) * Macromolecules packaged into membrane-bound protocells – Separate internal chemistry from external conditions * Self-replicating molecules arise
51
self replicating DNA
- 1st genetic material -> probably RNA, not DNA * DNA, arisen from RNA template: – more stable and more accurately replicated
52
Exploring Early Life: Fossil Record
- Stratification - Radiometric Dating - Evolutionary Steps
53
Stratification
- exploration with rocks (stromatolites) - rapid change
54
Radioactive dating
- radioactive decay (organic material C14 - C12) - rock-aging (including U-Pb dating) C14 -> constant, continually generated. Once its locked up in matter it decays (half-life) C12 -> organic, does not last
55
Evolutionary steps
our jaws: hinge, was very far back. - we grind our food to digest plants much more efficiently
56
Geologic time perspective
earth = 4.6 billion ya
57
Geologic Record
Phanerozoic, Proterozoic, Archean, Hadean
58
Single celled organisms
3.6 bya - prokaryotes - stromatolite fossils - layers of a rock from prokaryotic films, fossiled with layers
59
O2 revolution
2.4-2.7 bya - photosynthesis in water - reacted with iron, leaving evidence in rock layers -> rust - high O2 concentrations released into atmosphere, a lot of prokaryotic organisms died -PRIOR, OXYGEN was POISONOUS
60
First eukaryotes
1.8 bya - endosymbiosis -> engulfing - mitochondria and chloroplasts
61
Early multicellular eukaryotes
1.2 bya - protazotic era - volvox, green algae (volvox is photosynthesis maker)
62
Cambrian explosion
535-525 - geological layers Cambria in Whales Australia - fossil record goes from relatively few fossils to a big boom in hard fossils found (primitive life forms) - boom in diversity - after major extinction
63
Colonization of land
prokaryotes: 1 bya fungi: 500 mya shortly after Cambrian explosion - mycorrhizae, ancient symbiosis
64
Continental drift
Pangea 252 mya, Laurasia and Gondwana landmasses 135 mya, present day continents 66 mya, collision of India with Eurasia 45 mya
65
Extinction and speciation
- rise and falls - ex. "rise of mammals" during "fall of dinosaurs" (Cretaceous period) - adaptive radiation of mammals, branching of animals
66
Mass extinctions (6 main extinctions)
Top 2 - permian (due to volcanic activity), and cretaceous (dinosaurs)
67
Effects of developmental genes
Developmental timing shifts (Humans -> juvenile skulls) Spatial pattern shifts (ex., homeotic genes) - more development for our brains than we did for the human body as infants/in uterus - Deer and moose, babies start running within minutes
68
Systematics
* The analytical study of the diversity and relationships of organisms * Both present-day and extinct organisms * Involves: phylogeny (relativeness) and taxonomy (specific species and traits)
69
Taxonomy
- Ordered division of organisms into categories – Involves naming species
70
Did King Philip Come Over From Germany Saturday
Domain (broad) Kingdom Phylum Class Order Family Genus Species (specific)
71
Naming species
Humans: Homo sapiens Note: * Italics * Genus name is capitalized * Species name is not capitalized
72
Taxonomy history
Carolus Linneaus (1707 – 1778) *Swedish naturalist *Systema naturae, 1748 *Hierarchical system *Gave scientific names (Genus species) *Two kingdoms – Plant and Animal - pushed that species could never change - not true
73
Phylogenetic's
Study of the evolutionary history of organisms – Uses cladistics = creating clades from molecular and morphological characters – Trees are testable hypotheses. (or cladogram) Build phylogenies following maximum parsimony or maximum likelihood.
74
Orthologous genes
* Gene differences after speciation (simple, common, single gene change)
75
Paralogous genes
* Gene duplication with divergence in a species (one of the duplicates can change or stay the same)`
76
Know how to build a Molecular Phylogeny Using Parsimony
.
77
know how to interpret cladogram
.
78
monophyletic group
all descendants of common ancestors
79
paraphyletic group (reptile)
all descendants minus 1 from ancestor
80
polyphyletic group (fish)
different lineages in one group
81
molecular clocks
apply time - looking at accumulations overtime, you can apply divergence over time

General Bio 3 (4 decks)

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