Midterm Flashcards
1
Q
what is evolution?
A
a change in heritable characteristics of a population over generations
2
Q
darwin evolution
A
descent with modification
3
Q
population genetics
A
change in population allele frequencies
4
Q
what are darwins 4 postulates
A
- variation
- heritability
- overproduction
- selection
5
Q
difference of evolution as fact and theory
A
-descent with modification from common ancestors is fact
-theory of evolution is facts, laws, hypotheses concerning the causes of evolution (still incomplete)
6
Q
what is an adaptation?
A
-heritable trait that increases individual’s fitness in comparison to others that do not have the trait
7
Q
what did Lamarck do?
A
-described the inheritance of acquired characteristics (giraffes grew longer necks in their life time to reach leaves)
8
Q
what did Cuvier and Hutton do?
A
Cuvier: Catastrophism
Hutton: Uniformitarianism
9
Q
Catastrophism vs. Uniformitarianism
A
Catastrophism: periods of calm then catastrophe; new species generated after catastrophe
Uniformitarianism: Geological events over billions of years
10
Q
what is transformism?
A
-theory that changes occur within a lineage of populations but that lineage does not split; there is no speciation, and lineages do not become extinct
11
Q
what is the evidence for evolution?
A
- species change
-species go extinct
-fossil species resemble living species
-transitional forms exist
-vestigial traits occur
-the earth is ancient
-populations change - species are related
-related species live in same area
-homologies exist
12
Q
what are vestigial traits
A
-traits that are small and useless in one organism, but well developed and used in related organisms
13
Q
what is homology
A
-similarity due to shared ancestry between structures or genes in different species (yes or no)
14
Q
what is analogy
A
-similarity of a trait or characteristic’s form and/or function in different species but not as a consequence of common ancestry
15
Q
how does evolution happen?
A
- natural selection
- genetic drift
- mutation
- migration/ gene flow
16
Q
what is natural selection
A
-differential survival and reproduction of individuals due to differences in phenotype; leads to differences in individuals’ contribution to the next generation (results in change in frequency of heritable phenotypes)
-acts on phenotypes but leads to change in allele frequency
-acts on individuals but evolution occurs in populations
-has no greater purpose
17
Q
what is fitness affected by
A
- viability or mortality selection
-ability to survive and reach reproductive age - sexual selection
-ability to get a mate - Fecundity selection
-family size which is usually measured as the number of female eggs produced
18
Q
how to calculate allele frequency
A
-allele frequency= # copies of allele in population/ sum of alleles in population
19
Q
how to calculate genotype frequencies
A
-AA=pxp=p^2
-Aa=2pq
-aa=qxq=q^2
p^2+2pq+q^2=1
20
Q
Hardy-weinberg assumptions
A
- mating is random
- mutations do not occur
- the population is large, so genetic drift is minimal
- there is no migration or gene flow between populations
- natural selection does not occur
21
Q
what are the three models of selection
A
- Directional selection
-favours one extreme phenotype and the average phenotype changes
-genetic variation is reduced - stabilizing selection
-favours phenotypes near the middle of the range, maintaining the average
-genetic variation is reduced - disruptive selection
-favours both extreme phenotypes (at the ends) with little or no change to the population mean
-genetic variation is increased
22
Q
what is assortative mating
A
when individuals choose specific mates based on their phenotypes (not a random process)
23
Q
what is positive assortative mating
A
when individuals choose mates that share a particular phenotypic trait
-increases homozygote frequency (change in genotype frequency)
-does not change allele frequency (not evolutionary mechanism)
24
Q
what is negative assortative mating
A
-individuals choose mates with a different phenotype than themselves
-increases heterozygosity (change in genotype frequency)
-does not change allele frequency (not evolutionary mechanism)
25
what is inbreeding
-when individuals mate with close genetic relatives
-self fertilization is the strongest kind of inbreeding
-increases homozygosity (changes genotype frequency)
-can lead to bad alleles in population
-leads to reduced fitness (inbreeding depression)
-does not change allele frequency (not evolutionary mechanism)
26
what is genetic drift
-random changes in allele frequency as a result of randomly sampling gametes each generation
-allele frequency changes over time (is an evolutionary mechanism)
27
what is fixation
-when genetic drift occurs and over time one of the alleles will be lost
-the only remaining allele is fixed
28
what is the founder effect
-form of sampling error
-small number of individuals start another population and allele frequencies in the new population can differ from the original population
-changes allele frequency
29
what is a bottleneck
-sharp decline in population size that cab change allele frequency
30
what is a mutation
-permanent change in DNA sequence
-creates genetic diversity by creating new alleles
-is a mechanism of evolution
-often create deleterious alleles
-only interested in heritable mutations
31
what is migration
-movement of individuals and their alleles into or out of populations
-changes allele frequency (mechanism of evolution)
32
what is speciation
-evolution of new species
-ancestral species diverge
-happens when gene flow stops (mutation, natural selection, and genetic drift act independently on the populations)
33
what is the morphological species concept
-populations from the same lineage look similar
-problem when populations that look similar can't interbreed and populations that don't look similar interbreed
34
what is the biological species concept
-species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other groups
-problem that it only applies to sexually reproducing organisms and is difficult to determine if populations could interbreed when they are physically separated
35
what is reproductive isolation
Prezygotic
-formation of zygote is prevented (cannot physically mate)
Postzygotic
-zygotes form but do not survive (zygote doesn't form or is sterile)
36
what is ecological species concept
-populations that use the same ecological resources and face the same selection pressures
-problem: different species can have similar ecological roles
37
what is phylogenetic species concept
-define species based on evolutionary history (genetic similarity)
-species defined as the smallest monophylectic group in a phylogenetic tree
-requires no a priori categorization of groups
-can be applied to living and dead
-can be applied to asexual species
-problem: depends on availability of phylogenetic information and genetic material
38
what is allopatric speciation
-populations become geographically isolated from each other, preventing gene flow between them
39
what is a ring species
-species disperse around a barrier and thus change
40
what is dispersal
-individuals from a larger population move to a new habitat and start a new population that is isolated from the original population
41
what is vicariance
-a larger population is divided by physical barriers into smaller, isolated populations
42
what is sympatric speciation
-populations become reproductively isolated but are not geographically separated
-usually due to disruptive selection or assortative mating
-also occurs from meiosis errors that form polyploid offspring
-often a polymorphism forms (due to patchy habitat)
43
what is polymorphism
-the existence of more than one distinct form of individual (phenotype) in a population
44
similarities and differences of allopatric and sympatric speciation
similarities:
-both involve the formation of a new species via reproductive isolation of the gene pool from an existing species
-both occur when reproductive isolation over time results in genetic divergence between the new and ancestral population
Differences:
-allopatric involves physical separation of populations in different geographical areas
-sympatric involves a reproductive or behavioural separation among populations that occupy the same geographical area
45
what is secondary contact
-when isolated populations come back into contact
-either they cannot mate due to prezygotic barriers
-can interbreed and form hybrids
-if hybrids are not viable or have lower fitness than the parents then the species will become more divergent
-if hybrids have equal fitness then the two parental linages may interbreed and become one population
-if hybrids have higher fitness then hybrids may form a new species
46
what is reinforcement
-occurs when natural selection favours the formation of pre-zygotic barriers between the populations
47
what is ecology
-the study of how organisms interact with each other and their environment
-basic unit of ecology is the organism
-an organism's environment is everything around it
48
what is intraspecific
-intraspecific interactions occur among organisms of the same species
49
what is interspecific
-interspecific interactions occur between organisms of different species
50
what is organismal ecology
-focuses on morphological, physiological, and behavioural adaptations that allow individual organisms to live successfully in a particular environment
51
what is population ecology
-studies the changes in population demographics over time
52
what is community ecology
-examines the interactions among species and how they are affected by environmental changes
53
what is ecosystem ecology
-focuses on the movement of energy and nutrients among organisms and the physical environment (air, soil, water)
54
what is global ecology
-studies how the exchange of energy and matter between ecosystem and the atmosphere, hydrosphere, and lithosphere influence global conditions
55
what is biogeography
-the objective of biogeography is to understand the distribution and abundance or organisms
-an organism's range is the geographic area over which it is found
-the range of every species is limited by abiotic and biotic conditions
56
what is a niche
the full set of conditions an organism can tolerate and the full range of resources it can use
57
what is a fitness trade-off
-an evolutionary compromise between two traits that cannot be optimized simultaneously
58
what are hadley cells
-circular cells of air moving between 30° and equator
-warm air can hold more moisture than cold air
-air that is heated near the equator expands and rises
-as it rises it cools and expands even larger due to upper atmosphere and loses its moisture as precipitation
-this lowers its density and temperature
59
what is the rain shadow effect
-air absorbs moisture off of ocean and mountain range on coast forces air up
-rain falls on mountain side closer to ocean
-no more precipitation on other side of mountain
60
what is the coriolis effect
-deflection of air as a result of the area around the equator moving faster that the area around the poles
-in the northern hemisphere objects deflect to the right (hurricanes spin counter clockwise)
-in the southern hemisphere objects deflect to the left (hurricanes spin clockwise)
61
what are ocean surface currents
-driven mainly by the wind
-currents are created by transfer of momentum from wind to the water
-westerlies (30°-60°)
-easterly trade winds (equator)
62
the hydrosphere
-71% of earths surface is covered by water
-polar ice caps and glaciers contain 2% of all water but 70% of all freshwater
-freshwater in lakes and streams make up <1% of all water
62
the hydrosphere
-71% of earths surface is covered by water
-polar ice caps and glaciers contain 2% of all water but 70% of all freshwater
-freshwater in lakes and streams make up <1% of all water
63
what is primary productivity
the total amount of carbon dioxide that is fixed by photosynthesis per unit area
64
what is lentic
standing water (water that doesn't move) ex. ponds, lakes
65
what is lotic
flowing water ex. rivers, streams
66
zones of water in lakes
1. Littoral zone
-consists of the shallow water along the shore, where plants are rooted
2. limnetic zone
-offshore and comprises water that receives enough light to support photosynthesis
3. benthic zone
-made up of the bottom or substrate
4. photic zone
-regions of littoral, limnetic, and benthic zone that receive sunlight
5. aphotic zone
-portions of the lake that do not receive sunlight
67
what are the stratification layers
1. epilimnion (top): warm water zone of a lake in the summer. mixes and usually has lots of oxygen
2. metalimnion (middle): where thermocline is located (temperature changes rapidly)
3. hypolimnion (bottom): can become oxygen depleted in the summer
68
oxygen depletion
Summer fish kills
Winter fish kills
69
what is cold monomictic
-in cold arctic regions
-mix only once a year
-happens in the summer when ice has melted but surface of the lake does not get warmer than 4°C
70
what is warm monomictic
-lakes that do not get cold enough to develop ice in winter
-mix all winter long
71
what is a lakes trophic status
-amount of nutrients in lake
-3 important nutrients: nitrogen, phosphorous, and potassium
72
what is an oligotrophic lake
-lakes with vey few nutrients
-low productivity
-clear and cold
73
what is a mesotrophic lake
-intermediate amount of nutrients and productivity
74
what is an eutrophic lake
-very rich nutrients
-high productivity
75
what are wetlands
-shallow water habitats where the soil is saturated with water for at least part of the year
-different types are distinguished by water flow and vegetation
-have emergent vegetation
76
what are freshwater streams
-most are shallow enough that sunlight reaches the bottom
-the structure of a typical stream varies along its length and hence organisms very along length
-1st order is small streams up top
-as streams join they get bigger (decrease oxygen but increase nutrients)
77
what is an estuary
-forms where a river meets the ocean and freshwater mixes with salt water
-water flow fluctuates daily and seasonally which alters salinity
-species have adaptations that allow them to cope with variations
78
regions in the ocean
1. intertidal zone
-consists of a beach that is exposed to the air at low tide but submerged at high tide
2. neritic zone
-extends from the intertidal zone to depths of about 200m. defined by the end of the continental shelf
3. oceanic zone
-open ocean
4. benthic zone
-bottom of the ocean
5. photic zone
-regions that light reaches
6. aphotic zone
-regions that do not receive light
79
what is upwelling
-wind blows along coast moving water at surface
-surface water moves and forces offshore
-as surface water leaves it is replaced by nutrient water from the bottom (upwelling)
80
what is a biome
-distinct abiotic conditions and a dominant type of vegetation
-each biome is associated with a distinctive set of abiotic conditions
81
what is gross primary productivity (GPP)
total amount of chemical energy produced in a given area and time period
82
what is net primary productivity (NPP)
energy that can be put into growth and reproduction (remainder of energy from GPP that isn't used to keep the plant alive)
83
what is species diversity
1. species richness
-the number of different species in a given area
2. species abundance
-the number of individuals within a species in an area
84
what is adaptation
is a trait that increases your fitness relative to other individuals without that trait (increases your contribution to the next generation)
85
what is acclimation
is a change in morphology (or phenotype) in response to environment conditions
86
what is phenotypic plasticity
is the result of both genetic and environmental factors resulting in identical genotypes having different phenotypes in different environments
87
what is a reaction norm
the pattern of how a phenotype of a specific genotype changes over environmental conditions
88
what is genotype-environment factors/interactions
when genotypes respond to environmental variation in different ways
89
what is negative frequency dependent selection
the fitness of a phenotype decreases as it becomes more common
90
what is positive frequency dependent selection
the fitness of a phenotype increases as it becomes more common
91
what is the red queen hypothesis
-explains that a species must adapt and evolve not just for reproductive advantage but for survival competition
-predicts a negative frequency dependent relationship between host and parasite
92
what is homeostasis
a self regulating process where living organisms maintain a steady state of internal physical and/or chemical processes
93
physiological adaptation to temperature
1. Conduction
-energy transfer through molecular collision
-must have contact between surfaces
-depends on surface area, heat transfer efficiency, and temperature difference
2. convection
-energy transfer via moving fluid
-depends on the boundary layer
3. radiation and reradiation
-propagation of energy through space
4. latent heat exchange
-amount of heat energy either used or released with phase changes of water
94
what is Bergmann's rule
the idea that size of homoeothermic animals in a single closely related, evolutionary line increases along gradient from warm to cold temperatures
95
what is allen's rule
describes the broad pattern that animals in colder climates tend to have thicker limbs
96
what is countercurrent heat exchange
-warm arterial blood gives up its heat to cold blood returning from the extremities through veins lying in close contact with the arteries
97
what is a boundary layer
-the region around an object where the flow of fluids slows down
-large boundary layers are good for keeping warm in winter but bad at keeping cool in summer
-smaller leaves will have smaller boundary layers allowing for greater convection of heat
98
what is water balance
when the flow into a system is equal to the flow out of a system
99
what is residence time
-capacity of reservoir to hold water measured as the flow rate through the reservoir
-residence time=volume/flow rate
100
what is fluid balance
-the component of homeostasis that controls water balance within an organism
-fluid blance=ingestion+metabolism+absorption-evaporation-secretion
101
what are detritivores
heterotrophs that feed on dead tissues but does not mineralize organic material back into nutrients (includes scavengers)
102
what are decomposers
heterotrophs that mineralize dead organic material back into inorganic nutrients
103
what is homeorhesis
-steady flow instead of steady state
-dynamic system that returns to a specific trajectory instead of a specific point
104
what is resistance
the ability of a community to remain unchanged when challenged by disturbances
105
what is resilience
a measure of the rate a community can recover following a disturbance
106
what is hysteresis
the dependence of a state of a system on the history of that system
107
what is behaviour
action that alters the relationship between an organism and its environment
108
what is innate behaviour
-inherited or inborn
-inflexible
-stimulus triggers a response automatically
109
what is instinctual behaviour
-inborn or inherited
-inflexible
-ex. calves standing and walking right after birth
110
what is condition dependent behaviour
-flexible
-in response to environmental conditions
111
what is learned behaviour
-flexible
-changes in response to learning
-result from a specific experience in the life of an individual
112
what is sexual dimorphism
phenotypic differences between males and females
113
what is intrasexual selection
interactions between members of the same sex
114
what is intersexual selection
interactions between members of opposite sexes
115
what is polygyny
males mating with 2 or more females
116
what is polyandry
-females mating with 2 or more males
-can be cooperative were all males contribute to care of single clutch of eggs
117
risks and benefits of migration
Risks:
-energy expenditure
-predation risk
-time not reproducing
Benefits:
-exploit temporarily available resources (food)
-access habitat only seasonally accessible
-avoid cyclic hazards
-take advantage of different habitats during different life cycle stages
118
what is dispersal
movement of individuals in a population typically from an area of birth to a new location
119
what is altruism
behaviour with a direct fitness cost to the individual carrying out the behaviour and a direct fitness benefit to the recipient
120
what is Hamilton's rule
if Br>C then altruism is favoured by natural selection
B= fitness benefit
r= coefficient of relatedness
C= fitness cost
121
coefficient of relatedness
rBC=sum(rBAxrAC)
122
what is life history
the way that organisms allocate resources to growth, survival and reproduction. the sequence and timing of events in an organism's life
123
what is a life history trait
a heritable trait that determines some aspect of the life history of an organism
124
what is life history strategy
a pattern of life history traits that has evolved by natural selection over time in a population in response to ecological conditions
125
distribution of individuals
1. random
2. clumped
3. uniform
126
what is a cohort
a group of individuals of the same age that we can follow through time
127
what is a cohort
a group of individuals of the same age that we can follow through time
128
what is an age class
a group of individuals of a specific age
129
what is survivorship
proportion of individuals remaining alive from one age class to the next
130
survivorship curves
Type I: survivorship throughout life is high and most individuals survive until the max life span (humans)
Type II: constant survivorship throughout life (songbirds)
Type III: high death rates in early life (turtles)
131
what is net reproductive rate (R0)
-the growth rate of a population per generation
-if it is equal to 1 the population is stable
-if less than 1 the population is decreasing
-if more than 1 the population is increasing
-assumes immigration and emigration is negligible
132
calculate life tables
survivorship (lx)=survivors/initial population
average births/year/original female(lxmx)=survivorship (lx) x age specific fecundity (mx)
133
what is per-capita population growth rate (r)
-the difference between the birth rate and death rate per individual
- r=b-d
134
what is generation time
G=sum(xlxmx/R0)
x- age category
lxmx- age specific fecundity
R0- net reproductive rate
135
how to estimate r (growth rate)
r=ln(R0)/G
136
what is population growth
the size of population can be estimated for any given generation using the following growth equation
Nt=N0e^(rt)
137
what is maximum intrinsic growth rate
defined as when birth rate per individual are as high as possible and death rates per individual are as low as possible
delta(N)/delta(t)=rmax x N
138
what is exponential population growth
when r does not change over time. the population growth rate does not depend on the number of individuals in the population (density independant)
139
what is density independent
population growth increases in the size of a population do not affect r
140
what is density dependant
when population density gets high, the population's per capita birth rate decreases, and the per capita death rate increases, causing r to decline
141
what is carrying capacity (K)
maximum number of individuals in a population that can be supported by a habitat
142
what is precocial
longer gestation, young are born at a more advanced developmental stage
143
what is altricial
young are born helpless
144
semelparous vs. iteroparous
one shot vs repeated reproduction
145
what are metapopulations
populations of populations linked by immigration and emigration
146
what are source sink metapopulations
if habitats are not uniform and differ in quality, populations with more resources and higher growth rates can rescue other populations from extinction
147
what is a true sink
population will go extinct if immigration is cut off
