Please enable JavaScript.

Coggle requires JavaScript to display documents.

TEST 4 - Coggle Diagram

- - - - Population size (N)
      - Exponential growth
        
        J-shaped curve
        
        Unlimited resources
      - Logistic growth
        
        S-shaped curve
        
        Typical of a population that
        
        self regulates
        
        Has a carrying capacity (K)
    - - Overshoot K
      - Result in die off
        
        Limited resources
    - - r = intrinsic growth rate
        
        Relevant for r > 0
      - N = population size
      - K = carrying capacity
      - 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 the quantity one minus N divided by 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
  - - - How long did 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
    - - x = age
      - Nx\= number of individuals alive at age x
      - Sx\= proportion of individuals of age x that survive to age x+1;
        
        Nx+1/Nx
      - lx\= proportion of individuals that survive from birth (age 0) to age x;
        
        Nx/N0
      - Fx\= average number of offspring born to a female while she is age x
      - lx(Fx) = average number of offspring per capita at age x
      - lx(Fx)x = average number of offspring per capita at time x, weighted by age x
    - - To predict if a population will grow or shrink, ecologists need to know birth and death rates for organisms at different ages as well as the current age and sex makeup of the population.
      - Life tables summarize birth and death rates for organisms at different stages of their lives.
      - Population age structure—Are there lots of: young individuals? Old individuals? Reproductive age individuals?; and similar questions
      - Population growth rate—How fast is the population size growing (or shrinking)? Population survivorship patterns—Does most mortality occur in the very young? The very old? Or equally across all ages?
  - - - Predator
        
        P
        
        Negative impact on prey
        
        Positively impacted by prey
      - Prey
        
        N
        
        Positive impact on predator
        
        Negatively impacted by predator
      - Population sizes are influenced by each other
    - - r = intrinsic growth rate
      - N = population size
      - K = carrying capacity
      - dN/dt = population change over time
      - Exponential growth
      - Logistic growth
      - Can similar model predator-prey growth and the impact each has on the other
    - - Range of interactions
      - Beneficial interactions +
      - Negative interaction -
      - Facilitation (+/+)
        
        Benefits both
        
        Mutualism
        
        Pollination
      - Commensalism (0/+)
        
        Benefits one, neutral to the other
      - Amensalism (0/-)
        
        Negative to one & neutral to other
      - Competition (-/-)
        
        Both are negatively impacted
        
        Competition for resources
      - Predation (+/-)
        
        Herbivory
        
        Parasitism
    - - 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
      - As prey number declines, there is not enough food to sustain a high predator population and thus predator death rate exceeds that of birth rate
    - - 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
        
        abiotic environment
        
        biotic interactions that occur between species
- - - - Allele frequency
        
        Number of copies of an allele in a population divided by the total number of alleles for that gene in a population
      - Genotype frequency
        
        Number of individuals with a particular genotype in a population divided by the total number of individuals in a population
    - - Number of copies of an allele in a population
      - Divided by
      - The total number of all alleles for that gene in a population
    - - Number of individuals with a particular genotype in a population
      - Divided by
      - The total number of all individuals in a population
  - - - Changes in a population’s gene pool from generation to generation
      - Factors
        
        Mutation
        
        Natural selection
        
        Genetic drift
        
        Migration
        
        Nonrandom mating
    - - Change in one of the 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 a population
      - Example: 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 effect
        
        Large population diminished suddenly
        
        Natural catastrophe
        
        Migration
        
        May increase in size again but unlikely to regain original diversity
  - - - Death does not mean natural selection has occurred
      - Differential survival
      - Survival due to phenotypes that are heritable
        
        Phenotype coded by genotype
- - - - Each chromosome has a partner
      - 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
    - - During Metaphase I
        
        Orientation of bivalents is random
      - During Metaphase II
        
        Orientation of sister chromatids is random
      - In general, the possibilities are 2n
        
        Ex: human with 46 chromosomes
      - 246 \= 7.04 x 1013
    - - During 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
      - Usually at least one 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 and eliminated
        
        Escape host-parasite negative impacts
      - Pollination
        
        Cross pollination vs
        
        Self pollination
  - - - 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
        
        Heterozygosity
        
        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, both alleles are the same
      - Segregation
        
        Alleles are segregated, separated, from one another during meiosis
        
        Each gamete contains only one allele for each gene
        
        Offspring inherit 2 alleles for a gene
        
        One 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 2 alleles