Ecology is the study of how living organisms interact with each other and their surrounding environment. Ecosystems are umbrellas of organisms and their interactions with each other and the environment. Ecosystems can describe the entire Amazon Rainforest or simply a rotting log on the forest ground. Because an ecosystem is shaped by abiotic and biotic factors, the world with its wide diversity of physical conditions creates a variety of environments. Within an ecosystem, producers provide food for consumers, and both of their carcasses are then broken down by decomposers. This simple food chain makes up intricate food webs within an ecosystem.
Ecology: The study of how living organisms interact with each other and their environment.
Abiotic Factor: A physical aspect an environment, also known as a non-living factor.
Biotic Factor: A living aspect of the environment.
Ecosystem: An ecosystem is a complex system that consists of all the biotic(living)and abiotic (physical) aspects of the environment.
Niche: The role of a species in its ecosystem, which includes the way that the species interacts with the abiotic and biotic factors in its environment.
Habitat: A location where a specific population of a species lives.
Competitive Exclusion Principle: The idea that two species cannot occupy the same niche in the same place for a long period of time.
Food Chain: A diagram showing a single pathway through which energy and matter flow through an ecosystem.
Food Web: A diagram that represents multiple path-ways through which energy and matter flow through an ecosystem.
Trophic Level: The feeding positions in a food chain or food web.
Biomass: Biomass: The total mass of organisms at a specific trophic level.
Producer (or autotroph): An organism that creates its own food. Can be divided into photoautotrophs and chemoautotrophs.
Consumer (or heterotroph): An organism that consumes other organisms for energy. Can be classified as a herbivore, carnivore, or omnivore.
Decomposer: An organism that breaks down the re-mains of producers and consumers and releases simple inorganic molecules back into the environment. Can be classified as a scavenger, detritivore, or saprotroph.
Organisms don't just live on their own isolated from the environment. Instead, organisms interact with the environment in a variety of ways. Studying these interactions is a part of ecology.
The environment has two factors:
Biotic factors include the other organisms in the environment. The presence of other organisms will affect an organism's growth and chances of survival.
Here are some important things to remember about ecosystems (also called ecological systems):
Energy enters ecosystems as sunlight or chemical compounds. Producers (also called autotrophs) use this energy to produce food for themselves and other organisms. There are two types of producers:
Consumers (also called heterotrophs) consume other living things to obtain energy. Consumers can be classified as:
Decomposers are an important part of the ecosystem because they break down remains and wastes and release simple inorganic molecules that producers can use. Decomposers include:
Food chains and food webs help illustrate how energy flows through the ecosystem.
The position an organism occupies on the food chain or food web is called the trophic level. Example:
Energy moves between each trophic level, but only about 10% of the energy of the previous trophic level passes to the next trophic level. Therefore, it is unrealistic to imagine an ecosystem with more than four or five trophic levels because usually by those levels, there is very little energy that passes through, making it difficult for the organisms in that trophic level to survive.