Ecosystems and energy flow
What an ecosystem is, food chains and webs, and how energy flows through nature. Read one part at a time and tap “I know this”. Then test yourself in the quiz.
Know it already? Jump straight to the quiz
What is an ecosystem?
An ecosystem is all the biotic (living) and abiotic (non-living) parts of an area together: plants, animals, water, soil and sunlight. The biosphere is the part of the Earth where life occurs. An ecologist studies how it all interacts.
- A habitat is the place where an organism naturally lives.
- A population is a group of the same species in an area; a community is all the populations together.
Who eats whom?
| Role | What it does |
|---|---|
| Producer | Makes its own food with the sun’s energy (plants) |
| Herbivore | Eats only plants |
| Carnivore | Eats other animals (meat) |
| Omnivore | Eats plants and meat |
| Scavenger | Eats the meat of dead animals |
| Decomposer | Breaks down dead matter and returns nutrients to the soil |
Energy flow
A food chain shows who eats whom and how energy flows. Several linked chains form a food web. Only about one tenth of the energy passes to each next level, so there are many plants and few predators.
Interdependence: organisms depend on each other. When one species disappears, the whole ecosystem is disrupted.
Remember this and test yourself
- An ecosystem is the biotic (living) and abiotic (non-living) parts of an area together.
- Producers (plants) make their own food with the sun’s energy; consumers eat other organisms.
- Herbivore: plants only; carnivore: other animals (meat); omnivore: both; scavenger: dead animals; decomposer: breaks down dead matter.
- Arrows in a food chain point to the organism that receives the energy; about one tenth passes to each next level.
- Interdependence: when one species disappears, the whole system is disrupted.
Write these points in your book. Read them again the night before the test.
Energy drops to a tenth at every step: 1 000 → 100 → 10 → 1. That’s why there are lots of plants and few lions.
Important words
First say what the word means, then turn the card over.
Match column A to column B
Tap a word in column A, then its meaning in column B. You can also start in column B.
True or false?
Read the question and the answer. Is the answer right? Tap True or False.
Now the real quiz!
The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.
Take the quiz: Ecosystems and energy flow- Read one part together and ask your child to tell it back in their own words.
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Follows CAPS for Grade 7 Social Sciences (Geography). Always check your teacher’s notes and textbook too.