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Year 11 Biology Exam Questions Part 1: Local Ecosystems


Year 11 Biology Exam Questions: Local Ecosystems

Assess your depth of knowledge and understanding for the Year 11 Biology module ‘Local Ecosystems’ by answering the following exam style questions below.

Detailed answers are provided at the bottom of the page.


Question 1

What is the difference between a population and a community?


Question 2

What is the difference between a community and an ecosystem?


Question 3

Explain why objects under the water are perceived to be blue.


Question 4

What is the pH range of acidic and basic solutions?


Question 5

What device would you use to measure the turbidity of a river?


Question 6

Describe the relationship between pressure and depth in an aquatic ecosystem.


Question 7

Name a sampling technique you would use for a sessile and mobile organism.


Question 8

What is the role of decomposers in the ecosystem?


Question 9

What are the equations for photosynthesis and cellular respiration?


Question 10

What is the role of nitrogen-fixing bacteria?


Question 11

In a food web, what does the direction of the arrow indicate?


Question 12

What percentage of energy is transferred between each trophic level?


Question 13

What is the difference between intraspecific competition and interspecific competition?


Question 14

Identify an example of a mutualistic relationship between species.


Question 15

Are the ‘wings’ of a sugar glider an example of a structural, behavioural or physiological adaptation?


Question 16

Sunken stomata, leaf hairs and a waxy cuticle are all adaptations for what?


Question 17

Describe what happens to toxins such as heavy metals and pesticides once they enter the food chain.


Question 18

Why do mangrove trees have pneumatophores?


Question 19

Identify a mechanism mangroves have to help them cope with the high salt levels of their environment:




1. A population refers to a group of individuals from the same species that live in the same geographical area, at the same time. A community refers to a group of populations that live and interact with each other

2. A community refers to a group of populations that live and interact with each other.  An ecosystem consists of all the living and non-living components of an environment

3. Although water does absorb certain wavelengths, it doesn’t absorb all wavelengths equally. Blue is the only wavelength of light capable of penetrating to great depths.

4. Below 7 is acidic, above 7 is basic, 7 is neutral. pH is on a logarithmic scale.

5. A Secchi disk.

6. Pressure increases with depth. They have a direct relationship.

7. Transect or quadrat for sessile organisms, capture-mark-recapture for mobile organisms.

8. Decomposers play a vital role breaking down organic molecules into simple compounds, which are returned to the soil. This allows plants to take up and reuse these nutrients.

9. Sunlight + water + carbon dioxide -> oxygen + sugar

Oxygen + sugar -> carbon dioxide + water + energy (ATP)

10. These bacteria convert nitrogen in the atmosphere (N2) into ammonia within the soil (NH4+). This is an essential part of the nitrogen cycle. Nitrogen is used to produce DNA and the proteins essential for life.

11. The direction of energy flow in the food chain, e.g. the arrow will point from an organism to the consumer that eats it.

12. Around 10%.

13. In intraspecific competition, individuals of the same species are competing for a resource, e.g. two pine trees trying to grow faster than each other to get more sunlight. In interspecific competition two different species compete for a resource, e.g.  lions and leopards hunt the same prey.

14. Flowers and insects, nitrogen-fixing bacteria and legumes, clownfish and anemones, lichen (fungus + algae)

15. Structural.

16. To reduce water loss in hot dry environments.

17. Heavy metals and pesticides take a long time to break down, so they accumulate in the tissues of organisms. There will be higher concentrations of these substances in organisms that live a long time or are at the top of the food chain.

18. They act like a snorkel, allowing the mangrove to breathe under waterlogged soil.

19. Excreting salt on the surface of leaves. Accumulating salt in old or dying leaves. Tissue in the roots allows water to enter, but excludes salt.



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Written by DJ Kim

DJ is the founder of Matrix Education and has over 20 years of HSC Physics teaching experience. He is the co-author of the Matrix Science program, course materials and assessments. He is also renowned for his ATAR & Scaling seminars and development of the first ATAR Calculator.

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