Back to: Environmental Biology 200 Level
Welcome to class!
Hello brilliant star! I’m so glad you’re here today. Have you ever stopped to think about how life around us is so connected? Imagine your mother cooking jollof rice — she needs rice, tomatoes, pepper, seasoning, and firewood or gas. If one ingredient is missing, the food isn’t complete. Nature works just like that! Every living and non-living thing has a role to play in keeping our environment alive and balanced. Today, we will be learning about Ecosystem Dynamics & Energy Flow — and by the end of this lesson, you’ll see how every plant, animal, and even you are part of this amazing system.
Ecosystem Dynamics & Energy Flow
What is an Ecosystem?
An ecosystem is a community of living things (plants, animals, humans, and microorganisms) interacting with non-living things (air, water, soil, sunlight, and temperature). Think of it as a Nigerian village: there are farmers, hunters, traders, and children — all living together and depending on one another. Nigeria has many different ecosystems, such as the rainforests of Cross River, the savannah grasslands of the north, and the swampy mangroves in the Niger Delta.
Ecosystem Dynamics
Ecosystem dynamics refer to the natural changes and interactions that keep an ecosystem balanced. For example, when there is too much fishing in Lagos waters, fish populations reduce, which affects fishermen, markets, and even the birds that feed on those fish. Nature is always adjusting, like a careful mother who balances ingredients while cooking.
Some factors that affect ecosystem dynamics include:
Natural events such as droughts, floods, or bushfires.
Human activities like deforestation, overgrazing, or oil spills (especially in the Niger Delta).
Biological factors, such as the overpopulation of certain species.
Energy Flow
Energy flow describes how energy moves through living things in an ecosystem. The sun is the ultimate source of energy. Plants (producers) capture sunlight and convert it to food via photosynthesis. Herbivores (primary consumers), such as goats or cows, eat these plants. Carnivores (secondary consumers), like snakes, eat herbivores. At the top are tertiary consumers like humans or eagles. Decomposers like fungi and termites break down dead organisms, returning nutrients to the soil.
Food Chains and Food Webs
A food chain is a simple path of energy transfer, such as: maize plant → grasshopper → chicken → human.
But life is not always that simple — many animals feed on different things. Chickens can eat both grasshoppers and grains. This creates a food web, which is a more complex network of energy flow. Food webs show how energy moves through different organisms.
Ecological Pyramids
Energy in an ecosystem can be shown using pyramids:
Pyramid of Energy: Shows energy reduces as you move up the chain. This is why lions are fewer than antelopes.
Pyramid of Biomass: Shows the total mass of organisms — for example, all grasses outweigh all cows.
Pyramid of Numbers: Shows the number of individuals at each level — many grasses, fewer zebras, and only a few lions.
Nigerian Examples
In a Yoruba village, we could have a food web like this: cassava plants (producer) → grasscutters (primary consumers) → snakes (secondary consumers) → humans (tertiary consumers). If the cassava plants are wiped out by disease, the whole chain is affected — showing how everything is connected.
Summary
- An ecosystem is a community of living and non-living things working together.
- Ecosystem dynamics involve changes and balance within these systems.
- Energy flows from the sun to producers, then to consumers and decomposers.
- Food chains, food webs, and ecological pyramids explain energy movement and balance.
- Nigerian ecosystems (savannah, rainforest, mangrove) show real-life examples of these dynamics.
Evaluation
- Explain why energy flow in an ecosystem is said to be one-way.
- Differentiate between a food chain and a food web.
- List and explain three types of ecological pyramids with examples.
- Mention one Nigerian ecosystem and describe its energy flow.
You’ve done so well today! Remember, you are also part of this ecosystem — your actions, like planting a tree or recycling waste, can keep nature healthy. Stay curious and keep learning with Afrilearn. I can’t wait to share the next exciting lesson with you!