Ch 53 - Population Ecology

Question 1

Describe dispersion patterns.

Answer 1

• Describes how individuals are distributed
• Depends on environmental patchiness, social interactions, and dispersal ability.
• Clumped: based on resource availability & social behavior, most common pattern
• Uniform: evenly spaced based on agonistic (combative) social behavior, a result of territoriality or limited resoruces
• Random: unpredictible spacing, presnent in homogenous environements with little to no social interactions

Question 2

Describe life tables and reproductive tables.

Answer 2

• Life tables describe age specific survival patterns, studied in cohorts
• Reproductive tables are age-specific summaries of reproductive rates

Question 3

Describe survivorship curves.

Answer 3

• A graphical represenattion of life tables
• Type I species: “late loss”
  
  • few, large offspring with parental care
  • Reproduce when older
• Type II species: “constant loss”
  
  • very common
• Type III species: “early loss”
  
  • many offspring, little or no parental care, reproduce when younger

Question 4

Describe semelparity vs. iteroparity.

Answer 4

• Semelparity is the one-time production of many offspring, occurs in variable or unpredictable environments
• Iteroparity is the regular production of fewer offspring, occurs in stable environments

Question 5

Describe r-selected vs. K-selected species.

Answer 5

• r-selected opportunists:
  
  • organisms well below carrying capacity
  • maximizes reproductive success
  • lots of offspring early & often
  • can become pests
• K-selected equilibrium species:
  
  • organisms close to carrying capacity
  • longer lived, fewer offspring, & increased­ parental investment
  • can become endangered

Question 6

Describe population growth density-independent vs. density-dependent factors.

Answer 6

• Density-independent factors: birth rates & death rates do not change with population density (ex: abiotic factors - pollution, temp. changes, overharvesting)
• Density-dependent factors: birth rates decreasing, death rates increasing, population density increasing (ex: competition, predation, food availabilty)

Question 7

Describe** abioitic **vs. biotic factors.

Answer 7

• abiotic: nonliving; referring to the physical and chemical properties of an environment.
• biotic: pertaining to living factors in an environment