BCOR 102: Final Exam Flashcards
Age structure
relative number of individuals in each age class
Ways to increase r
- Reduce age at first reproduction
- Increase litter size
- Increase number of litters
- Increase survivorship of juvenile and reproductive ages
exploitation competition
population growth rates indirectly reduced through use of shared resources
interference competition
behavior or activity that reduces the uptake efficiency of another species
Hutchinson niche
n-dimensional hypervolume that defines a range of conditions for which dn/dt > 0
realized niche
effects of other species in the enivornment
character displacement
shifts in body size or morphology of a species in the presence of a competitor
ecological assortment
if species are “too close” in size or morphology on one of them to go extinct
Allopatric
living apart
sympatric
living together
Assumptions of Loka-V predation models
- no migration, age/size structure, genetic structure, time lags
- no carrying capacity for V (rV)
- P is a specialist on V population (-qP)
- P&V encounter one another randomly in a homogenous environment (Walking Dead)
- Individual predators are insatiable (no limit to a predator can eat, constant line of dV/dt = 0)
Hypothesis 1: Habitat diversity hypothesis
more habitats -> more different niches -> more species can coexist
H2: productivity hypothesis
increasing biomass and richness of species at the bottom of the food chain increases diversity at higher levels
Keystone predator (foraging strategies)
specializes on competitive dominant prey species (richness goes up)
random predator
consumes prey in proportions in which it encounters it (richness goes down)
switching predator
prefers the most common species in an assemblage (richness goes up)
rare species specialist
prefers rare species (richness goes down)
keystone species
a species whose presence or absence leads to cascading effects on diversity
trophic cascade
reciprocal changes in abundance at different levels of a food chain
H4: Niche Overlap Hypothesis (3)
a. expand resource axis
b. increase resource specialization
c. increased tolerance of overlap
Assumptions of MW model
- source pool of P mainland species with persistent populations
- Probability of colonization is inversely related to distance or isolation of island
- probability of an extinction for a population is inversely related to population size
- population size is proportional to island area
- colonizations and extinctions of different species are independent of each other (species interactions aren’t important)
evolution (general)
sustained change in the phenotype of a system through time
evolution (biological)
change in allele frequencies of a population through time (adaptation and speciation)
pleiotropy
a single gene affects more than one trait
epistasis
gene-gene interactions where the expression of one gene affect the expression of another gene
polygenic
small additive effects of many genes on one trait
HW (hardy-weinberg) assumptions
- no mutations
- no migration
- random mating
- no natural selection
- large population size
- random segregation of alleles at meiosis
positive assortative mating
more frequent mating between similar phenotypes
random mating
mate choice is independent of genotype
negative assortative mating
more frequent matings between dissimilar phenotypes
inbreeding
more frequent matings between close relatives
Autozygous alleles
2 alleles in an individual that are identical by descent from a single ancestor
allozygous alleles
2 alleles in an individual are identical by descent from 2 different ancestors
Genetic drift
changes in allele frequency due to random segregation of alleles in small population (when N < 100)
Founder effect
a population is colonized by only a few individuals –> carry a small number of alleles
bottleneck
a population that temporarily shrinks in size
tautology
self-referencing definition
ex. “survival of the fittest”
Natural selection
differential survival (and/or reproduction) of individuals with heritable traits
Assumptions of Natural Selection
- Individuals exhibit variation in their traits
- At least some of that variation has a heritable component
- All individuals produce more offspring than can survive
- Particular trait variance enhance survival in particular environments
Mean fitness
average fitness of the individuals in the population after random mating and selection (w-bar)
Modern synthesis
- Evolutionary phenomenon
- changes in allele frequencies
- evolution of adaptions
- speciation
- can be explained by mechanisms consistent with Mendelian inheritance - evolution is gradual
- Natural selection is strongest mechanism of evolution
- Genetic diversity in populations reflects current + past selection
- Microevolutionary change can lead to macroevolutionary responses
Science
asking and answering of verifiable questions
Parsimony
favor simple explanation over complex ones
Consilience
Consistency or convergence with other established facts and ideas
Inductive method
- francis bacon
1. observation
2. hypothesis
3. predictions
loop
paradigm
a view of nature that implicitly defines legitimate questions and problems
Thomas Kuhn method
- Paradigm
- puzzle-solving
- anomalies
- crisis
- scientific revolution
Hypothetic-deductive method
-popper
1. observation and hypothesis
2. multiple hyothesis
3. try to refute hypothesis
Null Hypothesis
no biological mechanism at work, instead the patterns are produced by sampling error and other forms/sources of variation
Randomness
a mixture of measurement and sources of variation too complex to measure and/or not of primary interest
Type I error
incorrectly rejecting a true null hypothesis
Type II error
incorrectly accept a null hypothesis that is false
Ecology
distribution (=where things occur) and abundance (=population size)
Population ecology
group of (interbreeding) individuals of the same species living in the same place
Assumptions of exponential growth
- No I (immigration) or E (emmigration)
- No genetic structure; all genotypes have same survival potential
- No age or size structure: the birth and death rates do not depend on how big/old a specimen is
- Continuous growth with no time lags
- Constant b (birth) and d (death)
Assumptions of logistic growth
- No I (immigration) or E (emmigration)
- No genetic structure; all genotypes have same survival potential
- No age or size structure: the birth and death rates do not depend on how big/old a specimen is
- Continuous growth with no time lags
- Constant carrying capacity (K)
K
carrying capacity maximum number of individuals that can be supported in a local population
Semelparous
all reproduction occurs in a single age class
iteroparous
repeated reproduction in 2 or more age classes
Experimental Design
- Replication
- Randomization
- Independence
- measurement of uncontrolled covariates
- Appropriate controls
randomization
individuals are assigned randomly to different treatment groups
Independence
responses of individuals in one treatment do not affect responses in a different treatment
ecotype
genetically distinct varieties from different locations
Common garden experiment
raise ecotypes under identical environmental conditions
local adaption
populations have highest fitness in the environments in which they originated
Speciation
evolution of reproductive isolation
Species (biological definition)
groups of populations that are reproductively isolated from each other
Species (taxonomic definition)
populations that can be reliably distinguished on the basis of morphological, biochemical, or genomic differences
Pre-mating isolating mechanisms
- seasonal, habitiat isolation
- ethological isolation
- mechanical isolation
Post-mating isolating mechanisms
Gamete mortality
-Mortality at the development of the sperm/egg
Zygote mortality
-Mortality of the embryo
Hybrid mortality
-Mortality after birth
Hybrid sterility
geographical mechanisms of speciation
- allopatric speciation
- peripheral speciation
- sympatric speciation
dichotomy
the branch points, the speciation event
Polytomy
more than 2 branch points at a speciation event
Sister species
two species sharing a most recent common ancestor
Sister taxa
any grouping sharing a most common recent ancestor
Monophyletic group
an ancestor and all of its descendants
Polyphyletic group
an incorrect grouping
Synapomorphy
shared derived character states
sex
the recombination of genetic material in two individuals (multicellular, eukaryotic) through meiosis and fertilization
disadvantages of sex
- energy, time investments
- exposure to predators
- exposure to STD
- transmots only 50% of alleles
Altruism
behavior increases the fitness of another individual at the expense of your own fitness
Group selection
groups of individuals that cooperate will have higher fitness that groups of selfish individuals
Kin selection
favors altruism towards related individuals
Advantages of sex
- avoidance of Muller’s rachet
- DNA repair easier with 2 copies
- evolutionary arms race between hosts & parasites
- sexual reproduction generates genetic variation in its offspring
Darwin: sexual selection
evolution has traits associated with successful mating
Bateman’s principle
sexual selection should be strongest on males who are potentially competing for access to females
Bateman’s steps
- male to male competition for access to mates
- attracting females
Female choice
- females look for cues indicating high male fitness
- resources, nuptial gifts
- run-away sexual selection: causes favorable trait to increase
