Ecology is the study of relationships between organisms and their environment. An organism’s environment can include other organisms. Therefore, ecology is also the study of relationships between organisms and organisms.
For example, relationships exist between plants and animals. Plants are a food source to herbivorous and omnivorous animals, while animals help fertilize, propagate, and pollinate plants.
An ecosystem is a community of organisms and their environment in a particular area. It is made up of two parts: biotic and abiotic.
The biotic part includes all living organisms in the ecosystem. While the abiotic part includes the physical environment in the ecosystem. Together, they interact and share relationships.
The physical environment of an organism consists of climate, geological features, and anything purely physical that influences life. It does not include plants, trees, etc. because those are living organisms; biotic.
An area without an organism is not an ecosystem. And, an organism and its environment is not always an ecosystem. An ecosystem functions by capturing and distributing energy and cycling nutrients.
If an organism and its environment does not function in these two ways, then there is not an ecosystem. For instance, if an organism appeared on a planet without life (prior to the organism), an ecosystem can only be established if the organism and its environment share a relationship, or can function together. Otherwise, the organism would die and eliminate the possibility of establishing an ecosystem.
Ecosystems vary in size, biodiversity, and physical features. One can consist of one organism and its environment. Or, one can be as big as the earth.
Do not confuse an ecosystem with a biome or habitat. A biome is a geographical area defined by the species present in the area. Though a biome may be considered a very large ecosystem, any ecosystem is not a biome.
A habitat is the natural environment of an organism. It is not defined as a functional system of organisms and their environment.
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