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Ecology & Evolution > FINAL FOCUS > Flashcards

FINAL FOCUS Flashcards

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1
Q

What is evolution?

A

The process by which populations of organisms change over time through variations in traits that are inherited across generations.

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2
Q

What is microevolution?

A

Small-scale evolutionary changes within a population over short periods of time, such as changes in allele frequencies.

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3
Q

What is convergent evolution?

A

The phenomenon where similar characteristics arise in unrelated species in different biomes.

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4
Q

What is macroevolution?

A

Evolutionary changes above the level of individual populations, typically involving large-scale transformations such as the origin of new species or major adaptive radiations.

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5
Q

What is the Phylogenetic Species Concept?

A

Defines species based on their evolutionary history and genetic distinctiveness using DNA sequences.

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6
Q

What are the shortcomings of the Phylogenetic Species Concept?

A

Requires extensive genetic data and advanced analysis. Difficult to determine at what point genetic differences define separate species.

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7
Q

What is a rain shadow?

A

Moist air rises on the windward side of a mountain, cools, and precipitates. The dry air descends on the leeward side, creating arid conditions.

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8
Q

How does the greenhouse effect work?

A

Solar energy absorbed at Earth’s surface is radiated back into the atmosphere as heat. Greenhouse gases absorb much of this heat, trapping some of it and causing warming.

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9
Q

What characterizes a Boreal/Taiga Forest?

A

Dominated by coniferous trees adapted to surviving long, harsh winters and short, wet summers.

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10
Q

What characterizes a Tropical Dry Forest?

A

Rich soil, strong seasonal variation in precipitation, consistently warm temperatures.

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11
Q

What characterizes a Temperate Forest?

A

Cold winters; hot and humid summers; year-round precipitation; dominated by deciduous trees in North America.

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12
Q

What characterizes a Savanna?

A

Dominated by grasses and herbs, few trees; seasonal precipitation; consistently warm temperatures.

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13
Q

What causes El Nino events?

A

A rise in air pressure over the Indian Ocean and a fall over the central and eastern Pacific, leading to a reversal of weather patterns across the Pacific.

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14
Q

What is the difference between climate and weather?

A

Weather is the short-term state of the atmosphere. Climate is the long-term pattern of weather.

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15
Q

What are prezygotic barriers?

A

Reproductive isolating mechanisms that prevent gametes from two different species from fusing together and forming a zygote.

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16
Q

What is an example of a prezygotic barrier?

A

Temporal Isolation: Species reproduce at different times.

Behavioral Isolation: Differences in mating behaviors prevent interbreeding.

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17
Q

What are postzygotic barriers?

A

Isolation occurs when gametes of two species fuse and form a zygote, but there is no gene flow between species.

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18
Q

What is an example of a postzygotic barrier?

A

Hybrid Sterility: Hybrids are unable to produce offspring (e.g., mules).

Hybrid Breakdown: Hybrid offspring are weak or infertile over generations.

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19
Q

What is sympatric speciation?

A

Species arise in the absence of geographical barriers, though some barrier interrupts gene flow.

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20
Q

What is an example of sympatric speciation?

A

Polyploidy in plants leading to reproductive isolation.

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21
Q

What is allopatric speciation?

A

Occurs when a population is geographically separated, leading to divergence due to genetic drift, mutation, and selection.

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22
Q

What is an example of allopatric speciation?

A

The formation of new species of squirrels on opposite sides of the Grand Canyon.

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23
Q

What is the Hardy-Weinberg principle?

A

The assumptions are: The population is large, mating is random, there is no mutation, there is no migration, there is no natural selection.

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24
Q

What is natural selection?

A

The differential survival and reproduction of individuals.

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25
What are the modes of natural selection?
Directional and stabilizing selection.
26
What did Lamarck propose?
Traits are acquired through use or via disuse.
27
What did Darwin contribute to evolution?
Presented more extensive evidence in support of evolution than Wallace.
28
What is heterozygote advantage?
Sickle cell anemia and cystic fibrosis persist in populations due to heterozygote advantage.
29
What are the benefits of sexual reproduction?
Greater genetic diversity, which increases the population’s ability to adapt to changing environments and resist diseases.
30
What are the costs of sexual reproduction?
Finding a mate, producing mating behaviors, and the two-fold cost of sex (females only contribute half their genes).
31
What is the Red Queen hypothesis?
Suggests that sexual reproduction allows species to evolve and stay ahead of constantly evolving threats like parasites, predators, and diseases.
32
What is the indirect benefit of female choice?
The underlying genetic quality, or good genes, of males with elaborate or bright ornaments.
33
What is genetic drift?
Evolution arising from random changes in genetic composition of a population from one generation to the next.
34
What is the founder effect?
A form of genetic drift describing the loss of allelic variation when founding a new population from a very small number of individuals.
35
What is an example of the founder effect?
Pitcairn Island’s settlers (27 people) resulted in distinct genotype frequencies from the surrounding British population due to limited genetic variation.
36
What is the bottleneck effect?
A sharp reduction in population size that reduces genetic diversity due to a smaller gene pool.
37
What is an example of the bottleneck effect?
Cheetahs suffered a bottleneck from climate changes and human activity, resulting in low genetic diversity and increased disease susceptibility.
38
What are beneficial mutations?
Mutations that increase the fitness of the individual that possesses it.
39
What are neutral mutations?
Mutations that neither increase nor decrease the fitness of the individual that possesses it.
40
What are detrimental mutations?
Mutations that reduce the fitness of the individual that possesses it.
41
What is assortative mating?
Occurs when individuals are more likely to mate with others that share certain traits.
42
What is an example of inbreeding?
Inbreeding can increase the frequency of homozygous genotypes, reducing genetic diversity. ## Footnote Potentially leading to inbreeding depression.
43
What are the three types of survivorship curves?
Type I: Low death rates during early and middle life. Type II: A constant death rate over the organism’s life span. Type III: High death rates for the young and a lower death rate for survivors.
44
What are R and K strategies?
R strategies focus on high reproduction rates, while K strategies focus on maintaining stable populations with lower reproduction rates.
45
What is density dependence?
Factors affecting population growth based on the population size.
46
What is a life table?
An age-specific summary of the survival and reproductive rates within a population.
47
What is exponential growth?
Continuous growth with no limits, producing a J-shaped curve.
48
What is geometric growth?
Discrete, non-overlapping generations, producing a stepped growth pattern.
49
What is logistic growth?
Growth that starts exponentially but slows as the population reaches carrying capacity, producing an S-shaped curve.
50
What does the island equilibrium model suggest?
Larger islands support more species because they have more resources and habitats.
51
What does Shannon diversity measure?
Species diversity.
52
What does the intermediate disturbance hypothesis state?
Moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance.
53
What is a niche?
An organism’s role within its ecological community.
54
What is the difference between fundamental and realized niches?
Fundamental niche: Set of conditions under which an organism can survive. Realized niche: Set of conditions actually used by an organism considering interactions with others.
55
What is competitive exclusion?
States that two species competing for the same limited resources cannot coexist indefinitely.
56
What is niche partitioning?
Occurs when two or more species coexist in the same habitat by utilizing different resources.
57
What is primary succession?
The development of communities in habitats initially devoid of plants and organic soil.
58
What is secondary succession?
The development of communities in habitats that have been disturbed but still contain organic soil.
59
What is biomass accumulation?
Describes stages through which forest ecosystems pass as they recover after a disturbance.
60
What is resistance in an ecosystem?
The ability to maintain structure and function in the face of potential disturbances.
61
What is resilience in an ecosystem?
The ability to recover from disturbances and return to its pre-disturbed state.
62
What is Gross Primary Production (GPP)?
The total amount of biomass produced by autotrophs in an ecosystem.
63
What is Net Primary Production (NPP)?
The amount of biomass remaining after autotrophs use some of that energy for respiration.
64
What is the carbon cycle?
The atmosphere and soil are major reservoirs of carbon, with organisms being sources of carbon through respiration or death.
65
What is the nitrogen cycle?
The nitrogen cycle has a lot of turnover, with the atmosphere and soil as large nitrogen reservoirs.
66
What is the phosphorus cycle?
An imperfect cycle because phosphate exists in a solid state and moves via rain or snow melt.
67
What is the hydrologic cycle?
A perfect cycle where water evaporates, condenses, and precipitates, ultimately returning to the ocean.
68
What are decomposers?
Organisms that break down initial material into smaller or more digestible components for fungi and bacteria.
69
Why are food chains short?
Because of inefficient energy transfer between trophic levels, with only about 10% of energy passed on.
70
What is bottom-up control?
Unidirectional influence from lower to higher trophic levels, driven by their diet rather than predation.
71
What is top-down control?
A higher trophic level influences the community structure of a lower trophic level through predation.
72
What are some animal defenses against predation?
Hiding, herding/schooling, camouflage or mimicry, and shell thickening.
73
What are some plant defenses against predation?
Producing toxins, thicker leaves, volatile chemicals, and vibration detection.
74
What is a numerical response in predation?
As prey population increases, the predator increases its numbers through an increase in the birth rate or immigration.
75
What is a functional response in predation?
Rates of predation can increase when prey are more abundant.
76
Why do predators of small prey cycle faster than those of large prey?
Smaller prey reproduce faster, leading to quicker fluctuations in their populations.
77
What is the numerical response in predator-prey dynamics?
As prey population increases, the predator increases its numbers through an increase in the birth rate or through immigration.
78
What is the functional response in predator-prey dynamics?
Rates of predation can increase when prey are more abundant.
79
Why do predators of small prey cycle faster than those of large prey?
Smaller prey reproduce faster, and their populations fluctuate more rapidly.
80
What is exploitative competition?
Indirect competition where one organism depletes resources, making them unavailable for others. ## Footnote Examples: Multiple animals using a watering hole & Limited nesting sites.
81
What is interference competition?
Direct competition where individuals physically prevent or limit access to a resource. ## Footnote Example: Elephant seals fighting for mates, Ants burying rival nests.
82
What is apparent competition?
Indirect interaction via a shared predator; one prey’s presence increases predator pressure on another. ## Footnote Examples: Invasive plant provides cover for predator that targets native species.
83
What is interspecific competition?
When any two species compete for a limited resource.
84
What is intraspecific competition?
The competition between individuals of the same species.
85
What does R* represent?
The minimum level of a resource a species needs to balance growth and mortality.
86
What is the Lotka-Volterra conceptual model?
Describes outcomes of competition using competition coefficients, but doesn’t identify which resource is limiting.
87
What are endoparasites?
Parasites that live inside the body and can be intra or intercellular. ## Footnote Examples: Tapeworms, roundworms, and flukes.
88
What are ectoparasites?
Parasites that live on the body. ## Footnote Examples: Lice, ticks, and fleas.
89
What is vertical transmission in parasitism?
When a parasite is transmitted from a parent to its offspring.
90
What is horizontal transmission in parasitism?
When a parasite moves between individuals other than parents and their offspring.
91
What is infection resistance?
The ability of a host to prevent an infection from occurring.
92
What is infection tolerance?
The ability of a host to minimize the harm once an infection has occurred.
93
What are intracellular parasites?
Parasites that live within the cells of the host. ## Footnote Examples: Protozoa, bacteria, fungi, and helminths.
94
What is obligate mutualism?
When one or both species must engage in the mutualistic relationship for survival. ## Footnote Example: The yucca plant depends on pollination by the yucca moth.
95
What is facultative mutualism?
A partner does not need to engage in a mutualistic relationship to be successful. ## Footnote Example: Cleaner wrasse cleans the mouths and gills of various fish species.
96
What is the Geographic Mosaic Theory?
when two species exert selective pressures on each other. According to the Geographic Mosaic Theory of Coevolution (John Thompson, 2005), this reciprocal selection isn’t uniform across a species’ range. Instead, it varies geographically. Species interact in multiple populations, leading to a mosaic of Hostposts & Coldspots.
97
What is kin selection?
Helping relatives increases indirect fitness by helping related individuals reproduce.
98
What is the Prisoner’s Dilemma?
A game theory thought experiment involving two rational agents who can either cooperate for mutual benefit or betray their partner for individual gain.

Ecology & Evolution (4 decks)

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