Marine Ecosystems and Human Impacts

Name:

Date:

Part 1: Read and Understand

Learning intention: We are learning how marine ecosystems function and how human activities can affect them.

Success criteria: I can describe a marine ecosystem, explain a food chain, use key vocabulary, and suggest a management strategy for an environmental impact.

Reading: Marine ecosystems

A marine ecosystem is a community of living organisms and non-living features in an ocean, estuary, reef or other saltwater environment. Organisms depend on each other and on conditions such as light, temperature, salinity and available nutrients.

Energy moves through a marine food chain. Producers, such as algae and seagrass, make their own food using sunlight. Small animals may eat producers, and larger animals eat smaller animals. Decomposers break down dead material and return nutrients to the ecosystem.

Biodiversity is the variety of living things in an ecosystem. High biodiversity can help an ecosystem remain healthy and recover from change. Human impacts such as plastic pollution, overfishing and climate change can reduce biodiversity and disturb food chains. Management strategies include reducing waste, setting fishing limits, protecting habitats and lowering greenhouse gas emissions.

Vocabulary matching

1. Biodiversity

2. Producer

3. Overfishing

4. Management strategy

A. A planned action to reduce or manage an environmental problem

B. Catching fish faster than populations can reproduce

C. The variety of living things in an ecosystem

D. An organism that makes its own food, usually using sunlight

Answers: 1. ____ 2. ____ 3. ____ 4. ____

Marine food chain

5. Number these organisms from 1 (first source of energy) to 4 (top consumer):

____ seal ____ phytoplankton ____ fish ____ krill

6. Use an arrow to show the direction of energy movement in the food chain.

Part 2: Impacts and Responses

7. What is a marine ecosystem? Include one living and one non-living feature.

8. Explain why producers are important in a marine food chain.

9. How could plastic pollution affect marine animals?

10. Explain one way overfishing can disturb a food chain.

11. Why is biodiversity important for ecosystem health?

12. Suggest one action people or governments could take to reduce the effects of climate change on marine ecosystems.

Impact–effect–management table

Complete the table for one human impact.

Human impact: ______________________________________________

Effect on marine life: _______________________________________

________________________________________________________________________

Possible management strategy: ________________________________

________________________________________________________________________

Exit ticket

One idea I learned today is _________________________________________________

One question I still have is ________________________________________________

Teacher Answer Key

Vocabulary: 1. C 2. D 3. B 4. A

Food chain: Phytoplankton = 1, krill = 2, fish = 3, seal = 4. Energy arrows: phytoplankton → krill → fish → seal.

7. A marine ecosystem is a community of organisms and non-living features in a saltwater environment. Examples include fish and sunlight, or algae and temperature.

8. Producers make food using sunlight and provide the starting energy for most marine food chains.

9. Animals may swallow plastic, become entangled, or suffer injury and reduced health.

10. Overfishing can reduce the number of one species, leaving predators with less food or causing prey populations to increase.

11. Biodiversity provides a range of species and roles, helping ecosystems remain stable and recover from change.

12. Acceptable answers include reducing greenhouse gas emissions, using renewable energy, protecting habitats or supporting climate adaptation programs.

Impact table: Answers will vary. Suitable examples include plastic pollution causing injury or ingestion, managed by reducing single-use plastics; overfishing reducing fish populations, managed by fishing limits; or climate change causing coral bleaching, managed by reducing emissions and protecting resilient habitats.