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Populations - Coggle Diagram

- - - - a group of actually or potentially interacting species living in the same location. Bound together by a shared environment and a network of influence each species has on the other.
        
        factors affecting interactions include
        
        biotic interactions that occur between species
        
        Range of interactions (+=beneficial, -=negative)
        
        Commensalism (0,+)
        
        Benefits one, neutral to other
        
        amensalism (0,-)
        
        Negative to one, neutral to other
        
        Facilitation(+,+)
        
        Benefits both; mutualism; pollination
        
        Competition (-,-)
        
        both are negatively impacted, competition for resources
        
        predation (+,-)
        
        Herbivory, parasitism
        
        Abiotic enviroment
      - Predator vs prey interaction
        
        Predator = P
        
        -impact on prey, + impacted by prey
        
        Prey = N
        
        +impact on predator, - impacted by predator
        
        Both influence population size
        
        Cycling
        
        At low prey and predator population sizes, prey increase exponentially
        
        As more food for predators is available, predator survival and reproductive success increases, resulting in predator population growth following that of their prey
        
        As predator populations increase, prey death rate exceeds birth rate, resulting in prey decline
        
        1 more item...
        
        Lotka-Volterra models
        
        dN/dt = rN-aNP
        
        dN/dt=rate of change with time of the prey population
        
        r=intrinsic rate of increase for prey
        
        N=number of prey individuals
        
        a=predator’s per capita attack rate (Number of prey eaten per predator per unit time)
        
        P= number of predator individuals
        
        dP/dt = faNP-qP
        
        dP/dt= rate of change with time of predator population
        
        f=constant, indicating predator’s efficiency at converting the prey it has eaten into new predators
        
        q=predator’s per capita mortality rate
      - Gene pool
        
        All of the alleles of every gene in a population make up the gene pool
        
        Relative Frequency
        
        Allele
        
        Number of copies of an allele in a population divided by the total number of alleles for that gene in a population
        
        genotype
        
        Number of individuals with a particular genotype in a population divided by the total number of individuals in a population (population should be half the allele amount since each person has 2)
        
        Frequencies in populations should add up to 1
        
        Mean = x
  - - - x=age, Nx=number of individuals alive at age x, Sx=proportion of individuals of age x that that survive to age x+1, Ix=proportion of individuals that survive from birth (0) to age x, Fx= average number of offspring born to a female while she is age x, IxFx= average number of offspring per capita at age x, Ix(Fx)(x)= average number of offspring per capita at time x, weighted by age x
    - - Ro=individual fecundity, Represents the expected number of offspring an individual will produce over its lifetime in the population.
        
        How to calculate = (survivorship column)(fecundity) or (Lx)(Fx)
        
        if R0=1, then population size does not change
        
        If R0>1, the population size increases.
        
        If R0<1, the population size decreases
    - - G=mean generation time, Represents average time between two consecutive generations in the lineage of a cohort
        (The average age between parent and offspring)
        
        Calculate by taking the sum of the Age-weighted fecundity column and then dividing by the net reproductive rate
    - - r=Intrinsic growth rate
        
        Calculated by taking the natural log of the net reproductive rate divided by the mean generation time.
        (Natural log of Ro)/G
        
        If r>0, the population size increases.
        
        If r<0, the population size decreases
        
        if r=1, then population size does not change.
  - - - Exponential (R species)
        
        j-shaped curve, unlimited resources
        
        Traits
        
        Annuals
        
        weedy
        
        Disturbed areas
        
        Little investment in defense
        
        many small fruits
        
        early maturity
        
        Formula
        
        dN/dt = r (N) #
      - Logistic (K species)
        
        s-shaped curve, self regulates, has carrying capacity (K)
        
        If species reach K they will start to die off due to limited resources
        
        Traits
        
        perennials
        
        Invest in defense
        
        Fairly stable habitat
        
        resource-intensive fruits
        
        Fluctuates around K
        
        late maturity
        
        Formula
        
        dN /dt =( r )(N) (1-N/K)
        #
      - Survivorship curve
        
        Visual representation of survivorship (how long did individuals survive)
        
        Types
        
        Type2
        
        Individuals have a constant chance of dying throughout their lives
        
        Some species can display all three, dependent on environment
        
        Type3 #
        
        Most individuals die young
        
        typical of r-selected species
        
        1 more item...
        
        Type1 #
        
        Most individuals survive until old age
        
        typical of K-selected species
        
        1 more item...
        
        Plotted logarithmically
        
        Take survivorship (lx) and multiply by 1000, take the log 10 of this value and plot it against age to produce your figure
    - - Formula parts
        
        r=intrinsic growth rate, N=Population size, K=carrying capacity, dN/dt= population change over time,
    - - grimes model
        
        Stress
        
        Resource availability
        
        nutrient
        
        light
        
        water
        
        Growth inhibitors
        
        toxins
        
        temperature
        
        Disturbance
        
        biotic
        
        Herbivory
        
        pathogens
        
        anthropogenic (pollution)
        
        abiotic
        
        fire
        
        wind
        
        3 life-stages
        
        S - Stress tolerators
        
        R - Ruderals
        
        C - Competitors
- - - - HW vs Punnett
        
        The frequency of gametes carrying a particular allele is equal to the allele frequency for a population in Hardy-Weinberg equilibrium.
        Multiplying the allele frequencies gives the proportion of each allele combination in the population.
        
        HW equations
        
        we always use p and q rather than choosing an upper and lowercase letter to represent alleles:
        
        The frequency of the dominant allele is represented by p
        The frequency of the recessive allele is represented by q
        
        p+q=1
        
        (p+q)^2=1^2
        
        p^2+2pq+q^2=1
        
        p^2= genotypic frequency of RR
        
        2pq= genotypic frequency of Rr
        
        q^2= genotypic frequency of rr
  - - - occurs when the population stabilizes on a particular trait value and genetic diversity decreases.
        
        population mean stabilizes on a particular non-extreme trait value; pushes population towards average trait
        
        x0=x1
        var0>var1
    - - occurs when individuals with traits on one side of the mean in their population survive better or reproduce more than those on the other.
        
        mode of negative natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.
        
        x0≠x1
        var0=var1
    - - occurs when individuals of intermediate phenotype are less fit than those of both higher and lower phenotype, such that extremes are favored.
        
        extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups
        
        x0=x1
        var0<var1
- - - - Incomplete dominance
        
        Phenotype of heterozygote is intermediate between those of parent homozygotes EX: RedxWhite=Pink
      - multiple alleles
        
        Many populations have more than 2 alleles for a particular locus
        
        Breeding experiments to determine dominance
        Figuring out alleles is complex
      - Mutations
        
        Changes in the genetic makeup of an individual
        
        Types
        
        point mutation
        
        Single nucleotide change
        
        chromosome mutation
        
        Deletion
        
        segments of chromosome lost
        
        Duplication
        
        Part of the chromosome has doubled
        
        Inversion
        
        pieces rotate 180
        
        Translocation
        
        Exchange of parts between 2 nonhomologous chromosomes
        
        Transposons
        
        Movable genetic element
        Jumping genes
      - No crossing over
        
        Fail to mix alleles across homologs
        
        Chromosome inherited same as parent
        
        Only 2 gamete types possible rather than 4
      - polygenic inheritance (most traits are this kind)
        
        Multiple genes for one character
        
        Phenotype is cumulative result of combined effects of many genes
        
        Populations tend to have normal distribution and continuous variation
      - Epistasis
        
        One gene interacts with another (may interfere or mask)
      - Linkage
        
        4 haploid genotypes
        Not produced in equal numbers
        
        Recombinants less abundant
        Parentals more abundant
      - Pleiotropy
        
        Single gene with multiple effects on the phenotype
        
        Inheritance of a single gene which visibly influences several traits
      - polyploidy
        
        Having more than two copies (2n) of a chromosome
        
        2 types
        
        allo
        
        Meiotic error
        Mismatch during mating
        
        Second mating creates matched pairs
        
        auto
        
        Failed meiosis
        Self fertilization
        
        evolutionary significance
        
        Polyploid mask deleterious recessive alleles
        
        Relax selection pressure
        Accumulate mutations that eventually result in beneficial trait
        
        2 groups of ancient duplications
        
        Common ancestor of seed plants
        
        Common ancestor of extant angiosperms
    - - Dominance
        
        Each individual has a unique genotype
        Genotype is made up of alleles
        Phenotypes determined by these alleles (and the environment)
        
        There is no guarantee that an allele will manifest
        
        Types of dominance
        
        Heterozygosity (Aa)
        
        One of 2 genes (dominant allele) has a detectable effect on an organism's appearance
        The other gene has no discernable effect (recessive allele)
        
        Homozygosity (AA)(aa)
        
        both alleles are the same
      - Segregation
        
        Alleles are segregated, separated, from one another during meiosis
        
        Each gamete (egg or sperm) contains only one allele for each gene
        
        Offspring inherit 2 alleles for a gene
        
        offspring inherit One from each parent
        During meiosis, 2 members of a gene pair separate from each other
        Each gamete has an equal chance to inherit either one of the genes
      - Independent Assortment
        
        Gene pairs that are not related (homologs) segregate independently
        
        Gene pairs that are not linked segregate independently
  - - - Homologous chromosomes
      - Resemble each other in size, shape & hereditary information
      - Each homolog is from a different parent
      - Interactions of genes on each sets of chromosomes determines the genetic characteristics
      - Each chromosome has a partner
    - - Meiosis (produces sperm or egg from gametes)
        
        Phases
        
        Metaphase II
        
        Orientation of sister chromatids is random
        
        Prophase I
        
        Synaptonemal complex forms
        
        Mixes the genes present in homologous chromosomes
        
        Results in new combinations not present in the chromosomes of the parental cells
        
        1 more item...
        
        Metaphase I
        
        Orientation of bivalents is random
        
        In general, the possibilities are 2n
        Ex: human with 46 chromosomes
        2^46 = 7.04 x 1013
    - - results in
        
        New combination of alleles from each parent
        
        Promotes heterozygosity
      - Advantages
        
        genetic diversity
        
        Bet-hedging to novel environments
        
        Multiple deleterious alleles can be bunched together and eliminated
        
        Escape host-parasite negative impacts