population ecology Flashcards
(105 cards)
1
Q
macroevolution
A
evolution on a large scale, phenotypic changes large enough new genera/higher taxa formed(Dinos to birds)
2
Q
how are organisms influenced by genetic variation
A
- some species are negatively impacted by lack of genetic variation(low fertility, deformed sperm, low survivorship). EX. cheetahs
- other pops unaffected by lack of genetic diversity
Ex. elephant seals thrived after almost extinct
3
Q
Irruptive(Malthusian growth)
A
Oscillation pattern of a population characterized by explosion(overshoot) followed by pop crash(dieback)
oscillation amplitude lower as time passes, pop settles around carrying capacity, but cc moving line because resources change
4
Q
Founder effect
A
the loss of genetic variation when a new isolated opo formed by a very small number of indivs form a larger population
5
Q
factors influencing carrying capacity
A
- Types of organism (simple vs complex), simple higher population
- available resources(environmental resistance). water, food, habitat, predatory, etc
6
Q
logistic growth
A
form of pop growth, per capita rate of growth decreases linearly w/ increasing pop density, also called sigmoid growth curve
takes place when pop’s per capita growth rate decreases as pop size approaches carrying capacity(K)
rate of growth constant changing as result of environ resistance approaches varying capacity
7
Q
ammensalism
A
interaction between two organisms/species, - / 0
8
Q
sink habitats
A
regions where mortality higher than birth rates usually due to unfavorable conditions
w/o immigration of individuals from other source habitats, pop would cease to exist
9
Q
microevolution
A
small evolutionary changes within pop or species
Ex. mosquitos resistance to DDT
10
Q
Density Dependence
A
Tendency for growth rate of pop to be affected by pop density
death rate of pop increase or birth rates decrease as density of pop increases
11
Q
Interference population
A
access to resources negatively affected by presence of other indivs
12
Q
Life history
A
pattern of survival and reproduction events during life of organism, traits include max body size, longevity, age at maturity, fertility etc
13
Q
Absolute population
A
actual total number of individuals of same species
14
Q
Stabilizing selection
A
indivs with alleles for intermediate traits are favored to survive and breed , occurs when environment unchanging reduces Ange of possible phenotypes
15
Q
Disruptive selection
A
India for extreme phenotypes at either end favored, occurs when environs favors more than one phenotype , more extremes allow range in population more chance to survive
16
Q
Gene Flow
A
Movement of allele into the gene pool of a population from one or more other population from one or more other populations
for this to happen, must be immigration of individuals from other populations and must breed with resident populations
17
Q
Random genetic drift
A
gradual changes in gene frequency of a population due to random events
18
Q
Inbreeding Depression
A
reduced biological fitness from inbreeding, often result of population bottleneck, reduces survival and fertility
19
Q
Fitness
A
avg repro success of entity from one gen to the next
fitness expressed as relative fitness where avg contribution of allele or genotype to the next gen compared w/ that of another allele or genotype(normally superior type)
Ie, How successful at passing on genes, longer able to survive and produce offspring
20
Q
Genetic Diversity
A
total # of genetic characteristics in the genetic makeup of a species
ranges widely from # of species, diffs withins species
the range of different inherited traits within a species. In a species with high genetic diversity, there would be many individuals with a wide variety of different traits.
Ex. diff dog breeds
21
Q
Speciation
A
A group of indivs that can share similar genes, can breed to produce offspring
3 types: directional selection, disruptive selection, stabilizing selection
22
Q
Ecosystem diversity
A
variations in environment within a geographical location and its overall impact on human existence and environment,
Ie, the variety of habitats, communities, ecological processes
23
Q
Types of diversity
A
Species, Habitat, Resource, Ecosystem
24
Q
Environmental DNA (eDNA)
A
shed cellular DNA from organisms found in the environment, scales, skin, feces, etc
25
Mark-Recapture
Method used in ecology to estimate pop size when impractical to catch entire population
capture # of indivs, tag, release, capture again, count how many marked
(# initially caught - #captured second time) / #marked recaptured
26
Metapopulation
collection of pops that have regular/intermittent gene flow between geographically separate units
requires suitable corridors or migration routes to exist between pops for gene exchange
27
Directional selection
indivs w/ alleles for single extreme genotype more likely to survive and reproduce due to a response to an environmental change
Ex. giraffe neck lengths, humans killing bigger game so evolving to small only
28
Molecular Clock
Technique using mutation rate of biomolecules to deduce time in prehistory when 2+ life forms diverged
DNA/protein seq./ RNA evolve at constant rate among most organisms
measures # of changes/mutations accumulated in gene sequences of diff species over time
29
Ecological Niche
Where and how indivs of species live, defined by location of habitat, where the species lives, what where how resources are obtained
30
Extinction Vortex
A downward population spiral leading toward extinction where inbreeding and genetic drift cause small populations to shrink in size, leading to a loss in genetic variation which prevents adaptation to changes
31
Biodiversity
variety of living things and interactions, changes over time as extinction occurs and new species evolve
3 lvls of diversity: species, genetic, ecosystem
32
Hardy-Weinberg Equilibrium
The state of equilibrium in Hardy - Weinberg where the genetic variability of a population is preserved from generation to generation and remains constant in the absence of other evolutionary influences
No mutation, large population, No immigration or emigration, random mating, no selection. (p+q) = 1 p^2 + 2pq q^2 = 1
33
K selection
selection of life history traits that favor populations that stay close to carrying capacity in a stable environment
Traits: Large size, delayed repro, long lifespan, multiple young in lifetime, few offspring, much parental care, strong competitive ability
34
Neutral/Balance Theory
Theory that most genetic variation is neutral with respect to fitness w/ the result that most evolution at the molecular lvl occurs by genetic drift
most genetic variation maintained by balance of selective forces
35
R selection
selection of life history traits that favor populations that result in the ability to rapidly increase in numbers
traits: small size, early reproduction, large # of offspring, short lifespan
36
Statistically defined communities
set of species whose abundances are significantly correlated, positively or negatively, over time
37
Ecosystem engineers
Organisms that physically change the environment around them through presence or behavior(beavers, trees blocking out sun, changes in humidity, etc)
38
adaptive radiation
process in which organisms rapidly diversify from an ancestral species into a multitude of new forms particularly when a change in the environment makes new resources available
39
Guild
grouped by behavior, a guild contains any species or organisms that exploit the same resources in similar ways
Ex. birds, rodents insects eating seeds
40
Functional group
collection of species that are all engaged in some similar ecological process
perennial grasses, nitrogen fixing legumes, etc
41
Intrinsic rate of natural increase (r)/Malthusian parameter
per capita rate of increase of pop with a stable age distribution when there is no inhibition of growth by infraspecific competition(r)
used to estimate pop growth
of births - # of deaths per gen
(BR/1000) - (DR/1000) = X%
(20-5)/1000 = 0.015%
42
Taxocene
set of taxonomically related species within a community
43
Realized Niche/Post interactive Niche
part of a fundamental niche that an organisms occupies as a result of limiting factors present in its habitat
Ie, the actual space that an organism habitats and resources it can use as a result of limiting pressures from other species
44
Fundamental Niche/Pre - interactive Niche
The full range of environmental conditions and resources an organisms can use and occupy esp with limiting factors absent
45
Gene introgression
the gradual movement of genes from one species into the gene pool of another, with some opportunity for hybridization between them, is an imp source of novel genetic variation, primarily done by backcrossing
46
Lotka Volterra Competition Model
derived independently, model describes competition between organisms for food and space based on logistic growth curve
4 possible outcomes:
species 1 wins, species 2 wins, stable coexistence, unstable coexistence
47
Evenness
the extent to which a group of species is uniform in number
most communities contain a few rare species, most species moderately abundant
48
simpson's index
Expressed as provability that 2 species chosen at random from community will be diff species
49
Interactively defined community
Subsets of a species in a particular place or habitat whose interactions significantly influence their abundances (salamanders)
50
Taxonomically defined communities
recognized by presence of one or more conspicuous species that either dominate the community through sheer biomass or otherwise contribute importantly to physical attributes of community(beech trees)
51
Biomes
Basic categories of communities that differ in their physical environments and in life styles of dominant organisms
52
Adaptive landscape
graph of avg fitness of a population in relation to genotypic frequency peaks on landscape
genotypic frequency high, peaks high
53
How do changes in population affect the gene pool based on pop size
in larger populations, the + -- of indivs doesn't really influcene the gene pool
in smaller pops, any + -- of indivs changes the genotypic landscape big time
54
minimum viable population
The minimum number of indivs with sufficient. genotypic variability needed in a population to ensure longtime survival
55
Altruism
decreasing your own fitness through acts of selfishness to ensure/increase the fitness of those related to you in order to pass on your genes
56
Natural selection
differential survival from one gen to the ext of Alternative forms of traits/entities with the result that organisms in the population best adapted to the local environment increase in frequency relative to less well adapted forms gen after gen
56
Biotic Potential
of offspring born under ideal living conditions,
the capacity of a species to reproduce under ideal environmental conditions
max growth rate of a pop if all individuals survive and produced max # of offspring
57
Gradualism
proposal that large changes in a phenotype are the result of many small changes
58
Competition
the interaction of individuals/pops struggling to gain advantage over limited resources
also direct/indirect interaction of organisms leading to change in fitness when organisms share the same resource
59
Environmental resistance
factors of the niche of a species that act to reduce a pop's growth rate
60
Competitive Exclusion principle
Ecological rule that no two species can occupy the exact same niche in the same habitat at the same time
61
Biological Species Concept (Mayr)
group/taxon of organisms can interbreed and produce fertile offspring, maintain species integrity
Ex. Wolves and dogs ok, Donkeys and horses no
62
Mortality
of organisms that die in a particular time period over # alive at the beginning of the period
#dead / # alive
63
Malthusian strategies
Short life, rapid growth, early sexual maturation, basically r selection
pioneers/colonizers, niche generalists, serve as prey, low trophic levels
64
Bottleneck
Severe, short lived reduction in population size, genetic variation in population severely reduced by genetic drift when the population is small
bottleneck is an extreme example of genetic drift
occurs when only a small population survive through chance
65
Intraspecific competition
competition for limited resources amongst individuals of same species, pop infraspecific competition drives evolution, ensures those most suited for survival survive and breed
Ex. two trees growing too close together fighting for light and nutrients
Ex. two male deer fighting for the right to mate with a female
Ex. Two hyenas fighting over a carcass
66
Evolution
change in the lineage of populations between generations
change in the genotypic/phenotypic frequencies
67
Migration
Gene flow amongst populations
or
movement of individuals from one population to another, may not involve gene flow
68
Stabilizing selection
In a stable environment not experiencing much change, indivs of a population who are phenotypically more similar in characteristics to the intermediate have better fitness
selection that promotes keeping a trait constant by selecting against the extremes of a phenotype, the intermediate of the phenotype has the highest fitness
69
Survivorship
probability of a newborn living to a particular age
70
Interspecific competition
competition between different species
Ex. cheetahs and lions hunting the same prey
Ex. pelicans and seagulls fighting over food
71
Inclusive fitness
fitness of a gene/genotype measured by the # of copies of identical genes by descent passed on to the next gen
the ability of an individual to transmit genes to the next generation
Directly to offspring 0.5, offspring of sibling 0.25
2 offspring, one niece 0.5+0.5+0.25 = 1.25
72
Climax community
a stable community that undergoes little to no change in species over time
73
Types of interspecific interactions
Commensalism, predation, mutualism, competition, parasitism, herbivory, amensalism
74
Kin selection
form of selection in which fitness of an allele is increased through altruistic acts to relatives, increases chance of rare alleles being passed on, alleles identical by descent received from a common ancestor
75
Resource partitioning
division of environmental resources by co-existing species such that the niche of each species differs by one or more significant factors from the niches of all other coexisting species
Ex. Mating at diff times of the year so that the highest energy need periods don't overlap, resources available for everyone
76
Exploitation
Competition where the use of resources by individuals reduces the lvl of resources available for others, causes adverse effects on others,
resources must be limited
77
Mechanism of speciation
the evolutionary process by which new species are formed
types: allopatric speciation, sympatric speciation
78
Allopatric speciation
groups from an ancestral pop evolve into separate species due to geographical separation
79
sympatric speciation
groups from ancestral pop evolve into separate species without geographical separation, evolve within a shared habitat
80
Functional response
relationship between predator's consumption rate of prey and either prey density or predator density
# of prey eaten per
81
population density
of indivs in a population in a given area
82
density dependent population control
greater effect as density increases
predation, parasitism, infectious diseases, competition for resources
83
frequency dependent selection
selection where the fitness of a genotype or phenotype depends on its frequency in the population
84
density dependent factors
regulation of the size of a pop by mechanisms whose effectiveness increases as population increases
85
Gamma diversity
The sum of Alpha diversity plus Beta diversity, the total species diversity in a landscape, the overall species diversity across communities in a larger geographic area
86
alpha diversity
the # of species in a small defined area(pond, alpine forest, etc), the local diversity found within a single type of habitat
87
Beta diversity
Within a larger geographical region the turnover/change in species composition among diff habitats that contribute to additional diversity
species diversity between 2+ local sites
88
Aposematic
colorations or markings that serve as warnings to would be predators that individuals is poisonous, foul tasting, or dangerous
Ex. neon dart frogs
89
Identical by descent
related indivs having the same allele passed down from a common ancestor
90
Coefficient of relatedness
probability of two individuals possessing the same rare allele by inheriting it from a common ancestor
in general, proportion of allies among two indivs that are identical by descent
91
Carrying capacity
The max capacity that a habitat/environment can infinitely sustain a certain number of individuals in a population
max pop size of a species that can be sustained indefinitely by a given habitat or area (K)
92
Evolutionarily stable strategy(ESS)
usually a heritable behavior which if adopted by most of the population, can't be improved upon by any other Strat, becomes established by natural selection (Hawk vs Dove)
93
Coevolution
joint evolution of 2+ interacting species where they evolve in response to each other
Ex. tougher seeds, tougher beak, cycle
94
Artificial selection
selection by humans of a chosen trait in a captive population, usually of a domesticated species
fitness determined by chosen trait, rather then by entire genotype/suitability to environment
95
Logistic strategies
k selection, long life, slower growth, late maturity, fewer and larger offspring, niche specialists, higher trophic levels, parental care, adapted to stable environment
96
Lamarkism
That gained phenotypic changes such as a finger getting chopped off will pass down that gene set to the next generation, disproven
theory of inheritance that suggested changes acquired during life were heritable
97
Mutation
random change in sequence of nucleotides in DNA molecule that leads to something other than original sequence, source of genetic variation
98
environmental resistance
combination of all factors that limit population growth
Ex. food, water, living space, disease, etc
99
Exponential/geometric growth
r selection
time it takes pop to double inside, increase rate remains constant proportionally to time
100
The mechanisms of competition(Schoemer)
1) consumption
2) pre-emption
3) overgrowth
4) chemical interactions, allelopathy
5) territoriality
6) encounter competition
101
Keystone species
species that has a disproportionately large effect on its natural environment relative to its abundance
Ex. Beaver
102
edge effect
changes in population or community structure that occur at the boundary of 2 or more habitats
103
Liebig's law of minimum
where species require several resources to grow, the growth rate is determined by the resource in shortest supply
104
