3.1-3.5

• Specialists Species

  • Smaller range of tolerance, or narrower ecological niche makes them more prone to extinction
  • Specific food reqs.
  • Less ability to adapt to new conditions
• Generalists Species

  • Larger range of tolerance, broader niche makes them less prone to extinction & more likely to be invasive
  • Broad food reqs.
  • High adaptability
• K-selected - "quality"

  • Few offspring and heavy parental care
  • Generally have fewer reproductive events than r-strategists
  • Long lifespan
  • More likely to be disrupted by environmental change or invasives
• r-selected - "quantity"

  • Many offspring, little to no care
  • May reproduce only once, but generally many times throughout lifespan
  • Shoerter lifespan, quick to sexual maturity
  • High biotic potential
  • More likely to be invasive
  • Better suited for environmental changes in conditions
• PARENTALS

  K-selected

  • Low biotic potential
  • Can be easily outcompeted for resources by invasives
  • Less likely to adapt and become extinct
• PARENTALS

  • High biotic potential
  • Death of parent doesn't affect offspring (low parental care)
  • Their population grows quickly, so they're not affected by invasives
  • Higher chance of adaptation
• Survivorship Curves

  • Faster drop in line = quicker die-off
  • Slower drop in line = longer avg. lifespan
• TYPES

  Type I (mostly K-selected)

  • High survivorship in early life due to high parental care
  • High survivorship in mid life due to large size
  • Rapid decrease in survivorship as old age sets in

  Type II (between r & k)

  • Steadily decreasing survivorship throughout life
  • Ex. birds, rodents

  Type III

  • High mortality early in life
  • Few make it to midlife
  • They die off slowly as they age
  • Ex. insects, fish, plants
• Carrying Capacity (K)

  • Highest pop. size in an ecosystem can support based on limiting resources: food, water, and habitat
  • Overshoot - when a pop. briefly exceeds carrying capacity
  • Consequence of overshoot - resource depletion
  • Die-off - sharp decrease in pop. size when resource depletion leads to many inidividuals dying
• Population Characteristics

  • Size (N) - total # of individuals in a given area at a given time
  • Density - # of individuals in an area
  • Distribution - how individuals in population are spaced out compared to each other
  • THIS INCLUDES: Random (trees), Uniform (territorial animals), Clumped (herd/group animals)
• Sex Ratio:

  • Ratio of males to females
  • Die-off or bottneck effect can lead to skewed sex ratio limiting population growth
• Density-Dependent Factor:

  • Factors that infleunce population growth based on the SIZE of the pop.
• Density-Independent Factor:

  • Factors that influence population growth NOT depending on the population size
• Biotic Potential (GRAPH)

  • Exponential growth
  • J-shape
• Logistic Growth (WEIRD SQUIGGLY LINE)

  • Initial rapid growth, then limiting factors that limit it to carrying capacity
• Biotic Potential

  • Maximum potential growth rate with no limiting resources
• Calculating Population Change

  • Inputs that increase pop. size: immigration and births
  • Outputs that decrease pop. size: emigration and deaths
  • FORMULA: Pop. size = (immigrations + births) - (emigrations + deaths)