Chapter 45 - Population & Community Ecology Flashcards
What is a Population?
a group of individuals of the same species living in the same area at the same time
What is studied in Population Ecology?
Abiotic and biotic factors that influence population size, density, and age structure
What are the main characteristics used in population ecology?
Population size & density
* N = total number of individuals
* Dp = # of individuals within a specific area
________ populations are typically more stable than ________ populations. Why?
Larger; smaller
* Increases genetic diversity
* Increased reproduction potential
Name a Population Ecology research method and its 2 types
Sampling - a representative portion of the population
* Quadrat - used for immobile organisms (like plants)
* Mark & Recapture - used for mobile organisms (animals)
What are the 3 dispersion patterns that can be found throughout a habitat?
- Uniform - equally spaced
- Random - no pattern
- Clumped - clustered in groups
What is Demography?
a statistical study of population changes over time, including birth rate, death rate, and life expectancy
________ populations have ________ birth rate and ________ death rate
Large; higher; higher
________ density populations may have ________ birth rate and ________ death rate
Higher; higher; higher
What ratio of population affects birth rate?
Sex ratio
Demography helps to predict what?
predict whether a population will grow or decline over time
What are Survivorship Curves?
number of individuals surviving at each age interval vs. time
What is a Survivorship Type I Curve?
- low death rate in early & middle years
- higher death rate in older individuals
- found in species that produce a low number of offspring/parent and provide high amount of parental care
- Elephants, Apes, etc.
What is a Survivorship Type II Curve?
- Consistent mortality over entire life
- Found in species that produce few offspring/parent and provide significant but brief amount of parental care
- Birds, rodents, etc.
What is a Survivorship Type III Curve?
- Very high death rate in early life
- Death rate declines as individuals age
- Found in species that produce many offspring/parent and provide little or no parental care
- Plants, fish, insects, etc.
What are Life Histories?
the collection of traits that affect the timing of reproduction and survival (i.e. genetically determined traits that are the product of natural selection)
Define Fecundity
potential reproductive capacity of an individual
Fecundity is ________ related to amount of parental care
Inversely
* Increased parental care → fewer offspring produced and at an older age
* Decreased parental care → more offspring produced and at a younger age
Fecundity is based on ________
energy budgeting
Describe the Early Reproduction energy trade-off strategy
- Individual reproduces at an early age
- Produces more offspring but at the expense of self growth and maintenance
- Often don’t live very long
Describe the Late Reproduction energy trade-off strategy
- Individual reproduces later in life
- Produces fewer offspring
- Provides greater parental care
- Individual may not live long enough to reproduce
Semelparity
- Individuals reproduce only once in their lifetime
- Use of most energy budget
- Produce many offspring, little or no parental care
- Low survivorship of offspring
Iteroparity
- Individuals reproduce repeatedly during their lifetime
- Budget energy for maintenance of life
- Produce few offspring, provide parental care
- High survivorship of offspring
Exponential Growth Population Model
- unlimited resources
- J-shaped curve
