Biodiversity and Its Importance
In 2016, CSIRO's Atlas of Living Australia recorded more than 97,000 species unique to Australia — including 80% of its reptiles and 87% of its frogs found nowhere else on Earth.
Printable Worksheets
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Q1 · A pine plantation has 10,000 trees but they are all the same species. A patch of rainforest the same size has 600 species of plants. Which patch has more biodiversity? Why?
Q2 · Name three things you eat in a normal week, and try to name the wild plant or animal each came from. (Tomato sauce, honey, fish fingers all count.)
● Know
- The definition of biodiversity
- The three levels: genetic, species, ecosystem
- Australia is one of 17 megadiverse countries
● Understand
- Why biodiversity matters for food, medicine and ecosystem services
- Why diverse ecosystems are more resilient to disturbance
- Why genetic diversity within a species matters too
● Can do
- Identify which level of biodiversity an example fits into
- List three ecosystem services humans depend on
- Explain why a single-species crop or forest is risky
- Biodiversity
- Species
- Ecosystem service
- Resilience
- Megadiverse
- Ability to recover after disturbance
- Variety of life at three levels
- A country with a huge share of world species
- Group that can interbreed and have fertile young
- A free benefit humans get from nature
Walk through a patch of original Australian bushland and count what you can see: different grass species underfoot, different bark beetles on different trees, different birds calling from different heights — that variety of life at every level is what biodiversity actually means.
| Level | What it measures | Example |
|---|---|---|
| Genetic diversity | Variety within a single species | Different breeds of dog; the many slightly different genes in a wild kangaroo population. |
| Species diversity | Number and variety of different species in an area | A rainforest with 600 plant species has higher species diversity than a wheat field with one. |
| Ecosystem diversity | Variety of different ecosystems on a region or planet | Australia has rainforests, deserts, alpine areas, coral reefs, mangroves, eucalypt woodlands — all in one country. |
All three matter. A country can have high species diversity but very low genetic diversity within each species (think: a tiny remaining population). Or it could have many ecosystems but each with few species. We want all three to be healthy.
- Different dog breeds
- A reef with 200 fish species
- Australia having deserts, reefs and rainforests
- Variety of genes in a wild koala population
- A wetland with frogs, fish, birds and reeds all coexisting
- Genetic diversity
- Genetic diversity
- Species diversity
- Species diversity
- Ecosystem diversity
Healthy ecosystems quietly do enormous amounts of free work that humans would otherwise have to pay for. These are called ecosystem services.
- Pollination — bees and other insects pollinate about a third of the crops humans eat (almonds, apples, watermelon, canola).
- Clean water — wetlands and forests filter water as it flows through them. Sydney's water supply still relies on the protected forests of the catchment.
- Climate regulation — trees absorb CO₂; the ocean absorbs heat. Both slow global warming.
- Soil formation — fungi, bacteria and worms break down dead matter to create new soil. Without them, no farming.
- Pest control — birds, lizards and parasitic wasps eat huge numbers of crop pests, replacing pesticides.
- Pollutant breakdown — soil microbes break down many pollutants over time.
One study estimated the global value of ecosystem services at over US$125 trillion per year — more than the world's entire economy. Most of it is invisible because nobody pays a bill for it.
Two more concrete reasons biodiversity matters:
- Food security. About 75% of the world's food comes from just 12 plant and 5 animal species. If a disease wipes out one of them (like the 1840s Irish potato blight, or the threat to the Cavendish banana today) and there are no alternative varieties, billions of people are in trouble.
- Medicine. About half of all modern medicines started life as a wild plant or microbe. Aspirin came from willow bark; penicillin from a mould; many cancer drugs from rainforest plants. Every species we lose is a possible cure we'll never find.
Australia's own wattles, eucalypts and bush plants have given us important chemicals — and most of them are still uninvestigated by science.
The three levels of biodiversity are , and . Diverse ecosystems are more to disturbance.
Of the ~200 countries in the world, only 17 are officially classed as megadiverse. Together those 17 hold over 70% of all known species on Earth. Australia is one of them.
| Group | Approximate Australian species | % found ONLY in Australia (endemic) |
|---|---|---|
| Mammals | ~390 | ~80% |
| Reptiles | ~1,000 | ~90% |
| Frogs | ~240 | ~94% |
| Flowering plants | ~21,000 | ~85% |
"Endemic" means a species exists naturally only in one place. Koalas, kangaroos, platypus, kookaburras, gum trees and wattles are all Australian endemics — they evolved here over millions of years of geographic isolation. That's why protecting Australian habitat is a global responsibility, not just a local one.
Wrong: "Biodiversity just means lots of animals." It also includes plants, fungi, bacteria and protists — plus diversity at the gene level inside one species and at the ecosystem level between regions.
Right: Biodiversity = variety of life at three levels: genetic, species, ecosystem.
Wrong: "A forest with one type of tree is just as good as a rainforest." A single-species (monoculture) forest is very efficient for timber, but one disease, one beetle or one fire can take the whole forest. Mixed forests have built-in backup species.
Right: Higher species diversity = higher resilience. If one species fails, others can fill its role.
Wrong: "Saving endangered animals is just sentimental." Most ecosystem services rely on a working web of species. Lose enough species and the services (pollination, soil, water filtering) start failing.
Right: Protecting biodiversity is also protecting food, water, medicine and climate — directly useful to humans.
Imagine all wild bees and other insect pollinators in Australia disappeared overnight. Predict: roughly what fraction of supermarket food would still be available three months later? Explain why in one or two sentences, then reveal.
How close was your prediction?
Nice — you grasped that pollination is huge but not 100% of food.
Good — ecosystem services often fail unevenly. Two-thirds left is still a disaster.
At the start of the lesson you were asked why roughly 80% of Australia's mammals are found nowhere else on Earth — and what happens if we lose them.
Now that you know about biodiversity and why it matters, write your full answer. What is it about Australia's geography and history that created so many unique species, and why would losing them be a problem beyond just losing the animals themselves?
Q1. Define biodiversity. Name and briefly describe the three levels, giving one example of each. (3 marks)
Q2. Identify three ecosystem services and explain how each one directly benefits humans. (4 marks)
Q3. A farmer plants 5,000 hectares of a single banana variety because it gives the highest yield. Evaluate this decision using the concepts of biodiversity, resilience and food security. (4 marks)
Answers
▾MCQ 1
D — Genetic (within a species), species (between species in an area), ecosystem (between ecosystems on the planet). A confuses biodiversity with "kingdoms"; the others are nonsense distractors.
MCQ 2
A — A wetland naturally filtering water is a classic ecosystem service. The others are economic goods or human work, not free benefits from nature.
MCQ 3
C — Megadiverse = one of 17 countries officially recognised as holding the bulk of world species. Australia is on the list with Brazil, Indonesia and others.
MCQ 4
B — Resilience = ability to recover from disturbance. Higher diversity means more "backup species" to cover lost roles.
MCQ 5
A — Variety within a species (different genes) is genetic diversity. Species and ecosystem diversity would involve more than one species or ecosystem.
Short Answer 1
Model answer: Biodiversity is the variety of life on Earth. (1) Genetic diversity — variety within a single species, e.g. different breeds of dog or many genes in a wild koala population. (2) Species diversity — number of different species in an area, e.g. a coral reef with hundreds of fish species. (3) Ecosystem diversity — variety of different ecosystems in a region or on the planet, e.g. Australia has deserts, rainforests, reefs and mangroves all in one country.
Short Answer 2
Model answer: (1) Pollination — bees and other insects pollinate roughly a third of our crops (almonds, apples, canola), letting them set fruit. (2) Clean water — wetlands and forests filter water as it passes through, giving us drinking water without the cost of treatment plants. (3) Climate regulation — trees absorb CO₂ and oceans absorb heat, slowing global warming and keeping the climate liveable. (Other valid: soil formation, pest control, pollutant breakdown.)
Short Answer 3
Model answer: Planting one variety on a huge scale is called a monoculture, and it has very low genetic diversity. While it can give the highest short-term yield, it is fragile: a single disease, fungus or pest that targets that variety can wipe out the entire crop because every plant is genetically the same. This makes the farm — and the wider food security of the country — risky. The Cavendish banana is a real example: nearly all supermarket bananas are clones, and a fungal disease (Panama disease TR4) currently threatens the whole industry. A more resilient approach would be to grow several varieties so that if one fails, others survive.