Chapter 4 vocab

The study of how organisms interact with each other and with their environments.
a group of individuals that interbreed and produce fertile offspring
Members of a species that live in the same area at the same time.
All of the populations in a particular area.
Includes all of the living things and their physical environments within a particular area.
Includes all parts of Earth that host life, with all of its organisms and environments.
Biotic Factors
Parts of an ecosystem that are living or used to be living.
Abiotic Factors
Parts of an ecosystem that have never been living
The specific environment in which an organism lives.
Is anything an organism needs, including nutrition, shelter, breeding sites and mates.
Population Size
Describes the number of individual organisms present in a given population at a given time.
Population Density
Describes the number of individuals within a population per unit area.
Population Distribution
Describes how organisms are arranged within an area.
Age Structure
Describes the relative numbers of organisms of each age within a population.
Age Structure Diagrams
Visual tools scientists use to show the age structure of populations.
Sex Ratio
Proportion of males to females in a population.
Survivorship Curves
Shows how the likelihood of death varies with age.
The arrival of individuals from outside a given area.
The departure of individuals from a given area.
A seasonal movement into and out of an area.
Exponential Growth
When a population increases by a fixed percentage each year.
Limiting Factors
Characteristics of the environment that limit population growth.
Carrying Capacity
the largest population size a given environment can sustainably support.
Logistic Growth
Describes how a population’s initial exponential increase is slowed and finally stopped by limiting factors.
Density-dependent Factor
A factor that changes with the density of a population.
Density-independent Factors
Limiting factors whose influence is not affected by population density.
Biotic Potential
Maximum ability to produce offspring in ideal conditions.