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Ecology Notes
What is Ecology?
The study of the interactions between organisms and their environment.
The environment consists of two parts:
Biotic: all of the organisms that live together and interact with one another.
Abiotic: all the physical factors of the environment that affect organisms in an area. Examples:
water, soil, light, temperature.
Organization in the Environment
Organism: A living thing
Population: A group of individuals that live in the same area at the same time.
Community: All of the populations of different species that live and interact in an area
Ecosystem: A community of organisms and its abiotic environment.
Biosphere: The part of Earth where life exists.
Habitat: The environment in which an organism lives.
Niche: An organism’s way of life within an ecosystem.
How Organisms Obtain Energy
Producer: Use sunlight to obtain food.
Consumer: Eat producers or other organisms for energy.
Decomposer: Get energy by breaking down the remains of dead organisms. Examples: bacteria, fungi
"Nature's recyclers"
Types of Consumers
Herbivore: eats only plants
Carnivore: eats only animals (meat)
Omnivore: eats plants and animals
Scavenger: animals that feed on bodies of dead animals
Flow of Energy
Food chain: shows the flow of energy from one organism to the next.
Food web: shows energy pathways
Energy pyramid: represents the amount of energy and number of organisms
Types of Interactions
1. With the environment.
Limiting factor: A resource that keeps populations from growing out of control. Examples: food,
water, living space
Carrying capacity: The largest population an environment can support over a long period of time.
2. With organisms
Competition: When two or more individuals or populations try to use the same resources such as
food, water and space.
Prey: An organism that is eaten. (hunted)
Predator: The organism that eats the prey. (hunter)
Relationships
Symbiosis: A close relationship (interaction) between two or more species.
Types of Symbiosis:
Mutualism: A relationship where both organisms benefit. Example: humans and intestinal bacteria
Commensalism: A relationship where one organism benefits and the other is unaffected. Example:
sharks and remoras
Parasitism: A relationship where one organism benefits and the other is harmed. Example: deer and
a deer tick
Ecological Succession
Succession: A gradual development of a community over time.
Primary Succession: The beginning of life in an area where living things did not previously exist.
Secondary Succession: The re-growth of a community that has been destroyed due to a natural
disaster (ex. fire, flood).