Biol-119-Unit 4

• Population


  All individuals of same species that live and reproduces in same place
• Population


  • Adapt due to natural selection
  • Abiotic (Nonliving factors)
  • Biotic (Living factors)
• Population Size


  Number of individuals of population
• Population Range


  Total area where population lives
• Population Density


  How crowded or dispersed; size divided by range
• Population Distribution


  • Random (equal chance of being anywhere, no influence on each other's locations)
  • Clustered (clump together, patchy resources, survival depends on each other)
  • Uniform (evenly spread apart, limited resources, too many will attract predators)
• Mark and Recapture Method

  1. Capture

  2. Mark

  3. Release

  4. Recapture

  5. Count
• Mark and Recapture Method


  n=size=marked 1st * 2nd capture/marked in 2nd)
• Lots of assumptions in Mark and Recapture Method
• Populations are based on organisms being the same species in the same location at the same time
• Per capita growth rate


  Rate of population growth per individual
• Up 40 is bigger deal for population of 20 compared to 500
• Average offspring per individual

  Dynamic value
• Constant r


  Rapid growth
• Continuous Growth


  Organisms born and develop at their own pace and then immediately can reproduce
• Exponential Growth


  More individuals, more possible reproductions, small population with abundant resources
• Intrinsic Rate of Increase


  Per capita grown at an instant
• Discrete Growth


  Number of germinating seeds from one gen determines # organisms in next, one discrete step changing size, seasonally or annual breeding
• Competition isn't good for either intraspecific (within species) or interspecific (between species)
• Carrying Capacity, K


  Maximum population size the location can manage, once reached, growth rate decreases
• Density Dependent Factors


  Birth and Death Rates, Competition, Predation
• Density Independent Factors


  Weather, Instantaneous change
• Logistic Growth


  Small population rapidly grows toward r-max, closer to K growth slows, exponential turns logistic
• Niche


  Combination of physical habitat and role/affect in habitat
• Fundamental Niche


  Every location that has the conditions so the species could live there, limited by competition and predation
• Realized Niche


  Where they actually stay, shown by invasive species
• Phylogenic Niche Conservation


  Tendency to keep aspects of ancestral niches
• Competition


  Use of mutually needed resource lowers availability to users, lose access to resource, lose energy fighting for it
• Competitive Exclusion


  2 species can't share exact same niche, move one's territory, extinction
• Resource Partitioning


  Divide resources between different species to minimize competition, reflects evolutionary diversification
• Antagonistic Interactions


  • Predation (predator eats prey)
  • Parasitism (eats host tissues)
  • Herbivory (eat plant parts)
• Mutualism


  Benefits trump costs for both participants, measured by natural selection in reproductive output, still always in self interest
• Mutualism


  • Nitrogen fixing bacteria live in soybean roots
  • Aphid insects give home for bacteria, bacteria provide essential amino acids
• Symbiosis


  Close interactions evolved over a long time
• Mutualism Types


  • Obligate Mutualism (need each other to survive)
  • Facultative Mutualism (can survive without each other)
• Commensalism


  One benefits, no effect on other participant
• Amensalism


  One is harmed, no affect on other
• Facilitation


  One species creates an environment that helps another
• Community


  All populations of multiple species in same place at same time, characterized by plants and animals
• Biodiversity


  Number of species, genetic sequences, cell types, metabolisms, communities