1. Limiting Factors
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2. Levels of Organization
Biosphere – the collection of all the ecosystems on the planet
Ecosystem – an area made up of all living organisms, as well as the climate, soil, water, rocks, and other non-living things
Community – a group of different species that live together in one area
Population – a group of the same species that lives in one area
Organism – one individual living thing

3. Sizes of Populations
The size of a population is constantly changing for one of any of the following reasons:
Births – an increase in the number of individuals in a population
Deaths – a decrease in the number of individuals in a population
Immigration – the movement of individuals into a population from another population
Emigration – the movement of individuals out of a population and into another population

4. How much can an ecosystem hold?
Carrying capacity – the maximum number of individuals of a particular species that the environment can support
Why can an environment only support so many individuals?
Food
Water
Space
Mates
Predators
Parasites
Disease
These are called limiting factors.

5. Types of Limiting Factors
Density-dependent limiting factor
Density-independent limiting factor
Competition
Unusual weather
Predation
Natural disasters
Parasitism
Human activities
Disease
Density-dependent limiting factor – factors affected by the number of individuals living in a given area
Density-independent limiting factor – factors that affect the size of the population, no matter what density of individuals live in an area.