Ecosystems and trophic levels

What is a population? A population is all the individual organisms found in a given habitat, of one species. So you could talk about a population of wolves in the woods. If you want to talk about the wolves and rabbits in the woods, then you’d be referring to a community. A community is made up of the various populations in a habitat. So the summation of all the living things in a given area is called a community. What then is an ecosystem?

An ecosystem comprises the community of living organisms in a habitat, together with all the non-living components such as water, soil, temperature, etc. called abiotic factors.

Why are different organisms of different species able to coexist in the same habitat? How come they don’t directly compete with one another and drive others out? Have a watch…

So that’s the last and loveliest new term: niche. It rhymes with quiche. A niche is the interaction, or way of life, of a species, population or individual in relation to all others within an ecosystem. It’s how it behaves, what it eats, how it reproduces, where it sleeps, etc.; a species’ niche is determined by both bioticfactors (such as competition and predation) and abiotic factors.

Different things may determine the population sizes within an ecosystem.

Where do we get all our energy from? Food. Where does the energy in food ultimately come from? Plants. Where does the energy in plants ultimately come from? Nowhere, they make it themselves through photosynthesis.

So is all the energy available to all living things on Earth down to photosynthesis? It sure is, my biologist friend, it sure is. Let’s take a humbling moment of meditation while adoring this photo of a plant:

One day that weird-looking thing in the middle will be a pineapple ^_^

But wait. Don’t plants also use their own photosynthesised goodies (glucose) to provide energy for their own business (growth, reproduction, etc.) via respiration, and waste stored energy in their tissues upon their death? Of course they do. So less must be available for whatever eats the….