Every organism is playing a specific and vital role in life’s food chain.
You may be a human and thinking that they are the king of the hill, but you may also be a bacterium playing under your feet.
Next Lesson: Organ Systems
This video transcript is here for your convenience. All organisms are hugely important to the system’s survival, no matter what kind of role they or you play. When you learn more about the ecosystem and the cycles in life, you’ll see terms like food webs and food chains. These terms are describing the same type of events that are happening when one organism is consuming another for survival.
Actually, the term food web is better and more accurate because all organisms are involved with a number of other organisms.
Cows can be food for humans, flies, or bacteria, and each one of these flies may be connected to microbes, spiders, or frogs. We can see dozens of these connections for all organisms, and when you draw all these connecting lines, what you’ll get is a web-like shape.
The producers are found at the beginning of simple food chains. Producers are vegetables and plants and plants are at the very beginning of all food chains that involve our Sun. All of our energy is coming from our Sun, and plants and vegetables are the organisms that are making food with this energy.
They are using a process called photosynthesis. Plants are also making tons of other nutrients to be eaten by other organisms.
Then we can also see photosynthetic protists that are starting food chains. We can find them floating around on the ocean’s surface, acting as food sources of tiny unicellular animals.
The consumers are actually the next link or step in a food chain. We recognize three levels of these consumers. It starts with the level of organisms that are eating plants. Scientists call these first organism groups of primary consumers. They are referred to as herbivores as well.
These organisms are the chain’s plant-eaters. It could be an elk, or it could be a squirrel. They are out there eating fruits and plants. They will not be eating animals.
Then come the secondary consumers that are eating primary consumers. Mouses could be primary consumers, and cats may be secondary consumers. We call these secondary consumers also carnivores. Carnivore stands for “meat eater.”
Then there is, in some ecosystems, a third consumer-level group named tertiary consumers (meaning “third level”). This group consists of consumers that are eating the secondary, and through that, the primary consumers. Tertiary consumers might be, for example, wolfs that eat cat and, through that, mouses.
Then we also know consumers that are called omnivores. Thee omnivores can be secondary consumers or tertiary consumers. For example, humans and also bears are considered to be omnivores: we are eating plants, meats, or just about whatever there is.
The decomposers are actually the last link in the food chain. So when you die, these decomposers are eating you. When you poop, these decomposers will eat that. When you’re losing leaves, they will eat that. Whenever a living thing dies, decomposers will get it.
These decomposers are breaking down nutrients in what we see as “dead stuff” and return this stuff to the earth’s soil. Producers will then be able to use these elements and nutrients once they’re in the soil. Decomposers are completing the system, and they return essential molecules to the chain’s producers.
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