6 Ecology and Environmental Biology
6.3 Ecosystems
Ecosystems
Dr V Malathi
An ecosystem is a community of living organisms such as plants, animals and microorganisms and their interactions with their abiotic (non-living) environment. Ecosystems can vary in size and complexity, from a tiny pond to a vast forest or ocean.
The Biotic and Abiotic factors of the Ecosystem
- Biotic Factors: These are the living parts of an ecosystem and include:
- Producers:are living things that use photosynthesis to create their own food, such as plants and algae.
- Herbivores (plant-eaters), carnivores (meat-eaters), omnivores (plant-and meat-eaters), and
- Consumers: Organisms that eat other living things for energy, including herbivores (plant-eaters), carnivores (meat-eaters), omnivores (both plant and meat-eaters), and decomposers (organisms like fungi and bacteria that break down dead matter).
- Decomposers : These organisms break down dead materials and returns nutrients to the soil.
- Abiotic Factors: These are the non-living elements of an ecosystem, which include:
- Sunlight: The majority of ecosystems rely on sunlight as their main energy source
- Water : is necessary for all living things.
- Soil: Supports a variety of species and gives plants nutrition.
- Climate and temperature :have an impact on whether species can survive and flourish in a given ecosystem.
Energy flow and Nutrient cycling in an Ecosystem
Energy Flow: Producers (plants and algae) use photosynthesis to absorb energy from sunlight that enters ecosystems. After consumers devour plants or other animals, energy is transferred to decomposers, which repurpose nutrients in the environment.
Nutrient cycling is the movement of elements such as carbon, nitrogen, and phosphorus through the environment and living things. In the carbon cycle, for example, carbon is taken up from the atmosphere by plants, passed on to animals when they consume the plants, and then released back into the atmosphere when creatures respire or decompose.
The food chain and food web are models that describe how energy and nutrients move through ecosystems via interactions among organisms.
Food Chain
A food chain is a linear series that illustrates how energy moves across an ecosystem as one organism eats another. Trophic levels are the names given to each stage of the food chain. This is an illustration of a basic food chain:
- Producers: Algae or plants that use photosynthesis to create their own nourishment. (For instance, grass)
- Primary consumers :Herbivores that consume producers are the Primary consumers. (grasshopper, for instance)
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- Secondary Consumers : Carnivores or omnivores that consume herbivores are examples of secondary consumers. (For instance, frogs)
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- Tertiary consumers : Carnivores that ingest secondary consumers are known as tertiary consumers. (for instance, a snake)
- Quaternary consumers :Top predators with few or no natural enemies are known as q