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EXAM 5 - Coggle Diagram

- - - - each chromosome has a partner
      - homologous chromosomes
      - resemble each other in size, shape, & heredity info
      - each homolog is from different parent
      - interactions of genes on each set of chromosomes determines genetic characteristics
    - - during metaphase I
        
        orientation of bivalents is random
      - during metaphase II
        
        orientation of sister chromatids is random
      - the possibilities are 2(^n)
        
        example: human w/ 46 chromosomes
        
        2(^46) = 7.04 X 10(^13)
    - - during Prophase I
      - Synaptonemal complex forms
      - mixes the genes present in homologous chromosomes
      - results in new combinations not present in the chromosomes of parental cells
      - usually at least 1 chiasma occurs between every pair of homologous chromosomes
    - - new combination of alleles from each parent
      - promotes heterozygosity
      - advantages include
        
        genetic diversity
        
        bet-hedging to novel environments
        
        multiple deleterious alleles can be bunched together & eliminated
      - pollination
        
        cross pollination
        
        self pollination
  - - - dominance
        
        each individual has unique genotype
        
        genotype is made up of alleles
        
        phenotypes determined by these alleles (and environment)
        
        no guarantee that an allele will manifes
        
        heterozygosity
        
        1 of 2 genes (dominant allele) has a detectable effect on an organism's appearance #
        
        other gene has no discernable effect (recessive allele)
        
        homozygosity
        
        both alleles are the same
      - segregation
        
        alleles are segregated/separated from one another during meiosis
        
        each gamete contains only 1 allele for each gene
        
        offspring inherit 2 alleles for a gene
        
        1 from each parent
        
        inherit a homologous chromosome
        
        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
        
        evidence provided from a dihybrid cross
        
        3:1 phenotypic ratio for each of the two allels
      - Monohybrid cross
        
        punnett square
        
        visual representation of offspring inheritance patterns
        
        monohybrid is a cross between 2 homozygous parents w/ different alleles
      - dihybrid example
        
        parental
        
        true breeding
        
        homozygous
        
        F1
        
        1st filial generation
        
        heterozygotes
        
        genotypic ratio
        
        allele combinations
        
        phenotypic ratio
        
        trait combinations
  - - - phenotype of heterozygote is intermediate between those of parent homozygotes
      - sanpdragons
        
        red X white = pink
    - - many populations have > than 2 alleles for a particular locus
      - Punnett square theoretical crossing works similar
      - breeding experiments to determine dominance
      - figuring out alleles is complex
    - - changes in the genetic makeup of an individual
      - point mutation
        
        single nucleotide change
      - chromosome mutation
        
        deletion
        
        segments of chromosome are lost
        
        duplication
        
        part of the chromosome has doubled
        
        inversion
        
        piece rotates 180
        
        translocation
        
        exchange of parts between 2 nonhomologous chromosomes
        
        transposons
        
        movable genetic element
        
        jumping genes
    - - fail to mix alleles across homologs
      - chromosome inherited same as parent
      - only 2 gamete types possible rather than 4
    - - multiple genes for 1 character
      - phenotype is cumulative result of combined effects of many genes
      - example = abscisic acid
      - most traits
      - continuous variation
      - populations tend to have normal distribution
    - - 1 gene interacts w/ another
      - may interfere or mask
      - ex. digitalis petal color
        
        1 gene impacts red intensity
        
        d light red
        
        D dark red
      - pigment location
        
        w throughout corolla
        
        W spots of nectar guide
    - - 4 haploid genotypes
      - not produced in equal #s
        
        recombinants less abundant
        
        parentals more abundant
    - - single gene w/ multiple effects on the phenotype
      - inheritance of a single gene which visibly influences several traits
      - ex. awn of wheat
        
        wheat w/ awns have greater yield than those w/out awns
    - - selfer
        
        small petals
        
        flower early
        
        seasonal drought
      - outcrosser
        
        large petals
        
        flower late
        
        seasonal drought
        
        physiologically tolerant
    - - having > than 2 copies (2n) of a chromosome
      - autopolyploid
        
        failed meiosis
        
        self fertilization
      - allopolyploid
        
        meiotic error
        
        mismatch during matin
        
        2nd mating creates matched pairs
    - - wheat
        
        original ancestral species had 14 chromosomes
        
        Durum wheat
        
        28 chromosomes
        
        Tetraploid
        
        pasta
        
        Bread wheat
        
        42 chromosomes
        
        hexaploid
        
        gluten for lofty bread
        
        result of sequential hybrid doubling and quadrupling
      - strawberry
        
        chemically induced
        
        prevent microtubule formation
        
        required for meiosis to occur properly
        
        produce diploid gametes
        
        during fertilization 2 diploid gametes fuse
        
        results in tetraploid (4n)
    - - 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
- - - - all of the alleles of every gene in a population
      - population=group of individuals of same species that occupy the same region & can interbreed
    - - allele frequency
        
        (#) of copies of an allele in a population divided by total # of alleles for that gene in a population
      - genotype frequency
        
        (#) of individuals w/ a particular genotype in a population divided by total # of individuals in a population
    - - (#) of copies of an allele in a population
        
        divided by
        
        total # of all alleles for that gene in a population
    - - (#) of individuals w/ a particular genotype in a population
        
        divided by
        
        total # of all individuals in a population
    - - predicts an equilibrium-unchanging allele & genotype frequencies from generation to generation-if certain conditions exist in a population
        
        no new mutations
        
        no genetic drift
        
        population so large that allele frequencies do not change due to random sampling effects
        
        no migration
        
        no natural selection
        
        random mating
      - provides a quantitative relationship between the allele & genotype frequencies
    - - consider a dimorphic population (2 alleles)
        
        all alleles in population add up to 100% or 1
        
        all genotypes in the population add up to 100% or 1
        
        red & white flower examples
        
        allele frequencies
        
        r=0.38, R=0.62
        
        0.38 + 0.62 = 1
        
        genotypic frequencies
        
        rr = 0.25, RR = 0.48, Rr = 0.27
        
        0.25 + 0.48 + 0.27 = 1
    - - genotypic frequency
        
        RR = 0.38
        
        Rr = 0.24 + 0.24 = 0.48
        
        rr = 0.14
      - frequency of gametes carrying a particular allele is equal to the allele frequency for a population in HW equilibrium
      - multiplying the allele frequencies gives the proportion of each allele combination in the population
    - - frequency of dominant allele represented by
        
        p
      - frequency of recessive allele 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
  - - - changes in a population's gene pool from generation to generation
      - factors
        
        mutation
        
        natural selection
        
        genetic drift
        
        migration
        
        nonrandom mating
    - - change in 1 of nucleic acids
      - some are apparent in phenotype
      - source of all new alleles
      - must be in gametes to be inherited
        
        male pollen sperm
        
        female ovule egg
    - - dimorphic
        
        2 phenotypes
        
        dominant-recessive systems
      - polymorph = many phenotypes in population
      - ex. Aquilegia
      - color variation
      - spur-length variation
      - can be due to a single nucleotide polymorphism
    - - random loss of alleles
      - acts most strongly in small populations relative to large
      - bottleneck affect
        
        large population diminished suddenly
        
        natural catastrophe
        
        migration
        
        may increase in size again but unlikely to regain original diversity
    - - plants "choose" their mates
      - pollinator vectors
        
        pollination syndromes
      - some of individuals reproduce more than others
        
        based on individual phenotypes
    - - male-male competition
        
        excess of pollen grains
        
        pollen tubes can interfere w/ one another
      - female choice
        
        barriers on stigma surface preventing germination
    - - movement of alleles into & out of a population
        
        immigration
        
        into
        
        emigration
        
        out of
      - can be impeded by
        
        environment
        
        life history
      - repercussions for
        
        GMO
        
        climate change
        
        speciation
    - - bottleneck from long distance dispersal
      - followed by adaptive radiation
      - ex. Hawaiian lobeliads
    - - 1 allele selectively advantageous
      - 2 (triangle) has more vigorous offspring
        
        over time, individuals w/ the 2 genotype are able to reproduce more & grow in #s
        
        overall vigor of population grows
        
        population size grows
    - - selection by humans
        
        increased frequency of desired trait
        
        elimination of undesired traits
      - crop breeders for thousands of years
      - ex. Brassica
  - - - death does not mean natural selection has occurred
      - differential survival
      - survival due to phenotypes that are heritable
        
        phenotype coded by genotype
    - - w/in population there is allelic variation arising from various factors such as mutations causing differences in DNA seq.
      - distinct alleles may encode proteins of differing functions
      - some alleles may encode proteins that enhance an individual's survival or reproductive activity
      - individuals w/ beneficial alleles more likely to survive & reproduce
      - over many generations, allele frequencies of many different genes may change through natural selection
      - significantly alters the characteristics of a species
      - net result = population that's better adapted to environment and/or more successful @ reproduction
- - - - exponential growth
        
        J-shaped curve
        
        unlimited resources
      - logistic growth
        
        S-shaped curve
        
        typical of a population that
        
        self regulates
        
        has carrying capacity (K)
      - population size (N)
    - - overshoot K
      - result in die off
        
        limited resources
      - human population size
    - - r = intrinsic growth rate
      - N = population size
      - dN/dt = population change over time
      - exponential growth
        
        dN over dt equals r times N
      - logistic growth
        
        dN over dt equals r times N times (1 - N)/K
    - - exponential growth
        
        dN/dt = rN
      - logistic growth
        
        dN/dt = rN[(K - N)/K]
        
        dN/dt = rN(1 - N/K)
    - - r-selected
        
        grow exponentially
        
        disturbed areas
        
        weedy
        
        annuals
        
        little investment in defense
        
        many, small fruits
      - K-selected
        
        fluctuate around carrying capacity
        
        fairly stable habitats
        
        perennials
        
        invest in defenses
        
        resource-intensive fruits
    - - plants must make trade-offs due to environmental necessities
      - many strategies exist
      - Grime's model
        
        Stress
        
        resource availability
        
        water
        
        nutrients
        
        light
        
        growth inhibitors
        
        temperature
        
        toxins
        
        disturbance
        
        biotic
        
        herbivory
        
        pathogens
        
        anthropogenic
        
        abiotic
        
        fire
        
        wind
        
        3 life stages
        
        C-competitors
        
        S-stress tolerators
        
        R- ruderals
  - - - to predict if population will grow or shrink
        
        ecologists need to know birth & death rates for organisms @ different ages as well as the current age & sex makeup of pop.
      - life tables
        
        summarize birth & death rates for organisms @ different stages of their lives
      - population age structure
        
        old? young? reproduction age?
      - population growth rate
        
        rate of pop. size growing/shrinking
        
        age of mortality occur
    - - x = age
      - Nx = # of individuals alive @ age x
      - Sx = proportion of individuals of age x that survive to age x + 1
        
        N(x+1)/Nx
      - Ix = proportion of individuals that survive from birth (age 0) to age x
        
        Nx/N0
      - Fx = average # of offspring born to a female while she is age x
      - Ix(Fx) = average number of offspring per capita @ age x
      - Ix(Fx)X = average # of offspring per capita @ time x, weighted by age x
      - Life table practice, R0
        
        calculate net reproductive rate (R0)
        
        calculated by taking the sum of the offspring/individual column
        
        represents the expected # of offspring an individual will produce over its lifetime in the population
        
        if R0 > 1 = population size increases
        
        if R0 < 1 = population size decreases
        
        if R0 = ! population size does not change
      - life table practice, G
        
        calculate the mean generation time (G)
        
        calculated by taking the sum of the age-weighted fecundity column & then dividing by the net reproductive rate
        
        represents average time between 2 consecutive generations in the lineage of a cohort
        
        average age between parent & offspring
      - life table practice, r
        
        calculate intrinsic growth rate (r)
        
        calculated by taking the natural log of the net reproductive rate divided by the mean generation time
        
        if r>0 population size increases
        
        if r<0 population size decreases
        
        if r=1 population size does not change
      - survivorship curves & age structure
        
        time individuals survive
        
        visual representation of survivorship
        
        type I, typical of K-selected species
        
        type III, typical of r-selected species
        
        dependent on environment
        
        same species can display all 3
      - Poa annua survivorship curve
        
        survivorship curves are plotted logarithmically
        
        take survivorship (Ix) and multiply by 1000
        
        take the log10 of the value
        
        plot against age to produce a figure
  - - - a group of actually or potentially interacting species living in the same location
      - bound together by a shared environment & a network of influence each species has on the other
      - factors affecting interactions include
        
        abiotic environment
        
        biotic interactions that occur between species
    - - range of interactions
      - beneficial interactions +
      - negative interaction -
      - facilitation (+/+)
        
        benefits both
        
        mutualism
        
        pollination
      - commensalism (0/+)
        
        benefits 1, neutral to other
      - amensalism (0/-)
        
        negative to 1 & neutral to other
      - competition (-/-)
        
        both negatively impacted
        
        competition for resources
      - predation (+/-)
        
        herbivory
        
        parasitism
    - - predator
        
        P
        
        impact on prey
        
        impacted by prey
      - prey
        
        N
        
        impact on predator
        
        impacted by predator
      - population sizes influenced by each other
    - - r = intrinsic growth
      - N = population size
      - K = carrying capacity
      - dN/dt = population change over time
      - exponential growth
      - logistic growth
    - - @ low prey & predator population sizes, prey increase exponentially
      - more food for predators available= predator survival & reproductive success increases
        
        resulting in predator population growth following that of the prey
      - predator population increases = prey death rate exceeds birth rate = prey decline
      - prey # declines = not enough food to sustain high predator population
        
        predator death rate exceeds that of birth rate
    - - dN/dt = rN - aNP
        
        dN/dt = rate of change w/ time of prey ppulation
        
        r = intrinsic rate of increase for prey
        
        N = # of prey individuals
        
        a = predator's per capita attach rate
        
        (#) of prey eater per predator per unit time
        
        P = # of peredator individuals
      - dP/dt = faNP - qP
        
        dP/dt = rate of change w/ time of predator population
        
        f = constant, indication predator's efficiency @ converting prey it has eaten into new predators
        
        q = predator's per capita mortality rate