Bio review

    Cards (173)

    • How long did you sleep last night?
    • We will be reviewing the Ecology Unit, including:
      Intertidal Ecology, Mark-Recapture Equation
      ● Population Ecology – population size, growth, life
      history traits
      Community Ecologyspecies interactions
      Ecological Successionprimary and secondary
      succession
      Ecosystem Ecology – energy flow, nutrient cycling
    • Ecology levels of organization
      • Individual
      • Population
      • Community
      • Ecosystem
    • Distribution
      Where species are found
    • Abundance
      The number of individuals of each
      species in a defined area
    • Abiotic Factors

      Non-living components of the environment
    • Range of Tolerance
      The range of abiotic conditions in which an organism can survive and reproduce
    • Biotic Factors

      Living components of the environment
    • You know what
      they mean right
    • Factors affecting distribution of species
      1. Dispersal ability
      2. Abiotic factors
      3. Biotic factors
    • Abiotic factors affect distribution
      Most abundant: optimal
      Present, less abundant: stressful
      Can't persist: range of intolerance
    • Biotic factors affect distribution
      Abundant at: less competition or predation, more food
      resources
    • One-way
      movement
    • Factors affecting abundance
      Abiotic factors: time, temperature, water
      Biotic factors: competition, mutualism
    • Does not need to survive well (%survival >0)
      In contrast to optimal range for survival.
    • The % cover of S. neomexicana is highest at the top of the hill and
      decreases dramatically towards the bottom. The % cover of S.
      neomexicana is 20.5% at the top of the hill and decreases 8.5% at the side
      and to only 3.0% cover at the bottom.
      The trend in % cover for other grasses was the opposite to the trend for S.
      neomexicana, the %cover of other grasses increased from the top to the
      bottom of the hill. The % cover of other grasses was 12.0 % at the top of the
      hill and increased towards the sides ( 35.5%) and bottom of the hill (47.5%).
      Considering all species, the tops of the hills had lower % cover of all grasses
      and the % cover increased towards the bottom of the hill. The total %
      coverage was 32.5% at the top and 50.5% at the bottom.
    • No information was given on statistical tests
    • Intertidal Ecology
      Environment changes periodically each day. Tide is low: terrestrial conditions, suboptimal or even
      lethal. Tide is high: marine conditions, optimal.
    • Intertidal Distribution
      • The length of time that an intertidal organism is
      exposed to terrestrial conditions depends upon its
      location in the intertidal zone.
      Located at higher tidal height → longer time exposed
      to air → only those marine organisms that can
      tolerate this live there
      More optimal when submerged in water
    • Abiotic factors affect upper limit of distribution
      Greater range of tolerance for low
      dissolved oxygen conditions
    • Biotic factors affect lower limit of distribution
      Predation: Intertidal organisms' predators are mostly
      marine organisms, so higher predation intensity
      when they are submerged.
      Competition: more competition (eg. for space) at
      optimal abiotic condition (lower intertidal zone).
    • Biotic factors affect lower limit of distribution
    • Population Ecology
      A population is a group of individuals of the same
      species that live in the same area at the same time.
    • If the population size decreased by 40% becaused
      their habitat decreased to 70%

      The population
      density decreased
    • Estimate Population Size
      Mark-recapture
    • Suppose that your trap 255 stickleback fish in a lab and mark
      them by clipping the first spine off their dorsal fins. One month
      later, you return to the lake and capture a total of 162 stickleback
      fish. 78 of these fish are marked. What is the estimated
      population size of stickleback fish in this lake?
    • Lincoln-Peterson Method Assumption
      • The population is closed (N̂ remains the same
      between sampling periods)
      Individuals are equally likely to be caught
      Individuals do not lose marks between sampling
      periods
    • Population Size Change
      Increase: Birth, Immigration
      Decrease: Death, Emigration
    • Per capita birth rate
      b = B/N
    • Per capita death rate
      d = D/N
    • Growth Rate
      r = b - d, -1 ≤ r ≤ 1
    • If b=d, then r=0 – population size is not changing
      If b>d, then r>0 – population size is increasing
      If b<d, then r<0 – population size is decreasing
    • Since r = b - d
    • Exponential growth
      • J-shaped curve
      constant r (density-independent)
      dN/dt increases
      Usually short-lived, occurs when:
      Unlimited resources
      Or, pop sizes are relatively small
    • Logistic growth
      • S-shaped curve
      Limiting factors restrict pop growth
      r declines when N approaches K (carrying capacity)
      r is density-dependent
      At N=K, b=d, r=0
    • the maximum population size
      that a particular environment
      can sustain at a given time.
    • When N is small, exponential &
      logistic growth look similar
    • Theoretically, N stays at K (continuous).
      Realistically, N fluctuates around K (discrete growth)
    • Carrying Capacity
      Changes when environment changes
      Differs among species
    • Limiting Factors
      environmental factors that limit the growth,
      abundance or distribution of a population
      Density-dependent factors (usually biotic)
      Density-independent factors (usually abiotic)
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