Ecology
- Study of the interactions among organisms and between organisms and their nonliving environment
- Individual, population, community, and the ecosystem
Individual level
How an individual organism fares in its surroundings
Population level
A group of individuals of the same species living and interacting in the same region
Community level
Interacting populations of different species
Ecosystem level
Species interacting with other species and the environment
Distribution pattern
- Organisms distributed in geographic space
- Depends on resources and interactions with other members of the population
- Reflect behavioral or ecological adaption
Random distribution
May allow individuals to maximize their access to resources
Clumped distribution
- When resources are unevenly distributed across the landscape
- Or when social behavior dictates grouping
Uniform distribution
-Results from territorial behavior
Growth rate
- Difference between the birth rate and the death rate
- Influenced by immigration and emigration
Immigration
Movement of individuals into a population
Emigration
Movement of individuals out of a population
Exponential growth
-Unrestricted growth of a population increasing at a constant growth rate
Logistic growth
- Starts off fast and then levels off
- Environmental factors will limit an organism’s ability to reproduce
- For example, access to habitat: the physical environment where an organism lives and to which it is adapted
Carrying capacity
- The maximum number of individuals that an environment can support given its space and resources
- Upper limit on the size of any population
Isle Royale
A number of factors influence the likelihood that wolves will kill moose
Population density
Number of organisms per given area
Density-dependent factors
-A factor whose influence on population size and growth depends on the number and crowding of individuals in the population
Density-independent factors
A factor that influences population size and growth regardless of the numbers and crowding within a population
Biotic factors
Living components of an environment
Abiotic factors
Nonliving components of an environment
Community
Group of interacting populations of different species living together in the same area
Ecological niche
-The space, environmental conditions, and resources that a species needs in order to survive and reproduce
Competitive Exclusion Principle
-One of the competing species will be driven to extinction
