Grade 12 STEM Practice Worksheet: Ecosystems

Ecosystems Practice Worksheet

Grade 12 STEM Ecosystems Practice Worksheet Advanced 5 Questions 14 Views

Classroom Worksheet

Grade 12 STEM Practice Worksheet: Ecosystems

Ecosystems Practice Worksheet

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Grade: Grade 12

Subject: STEM

Topic: Ecosystems

Time: 20 Minutes

Difficulty: Advanced

Questions: 5

Instructions:
Read each question carefully and show your reasoning where needed. Answer in complete sentences when appropriate. These questions increase in difficulty, so take your time and think like a scientist.

Skills Practiced:

Ecosystems
STEM
Critical Thinking
Problem Solving

1Question

Define the term ecosystem and name its two main components.

2Question

In a forest ecosystem, identify two abiotic factors and explain how each one can affect the organisms living there.

3Question

Construct a simple food chain from a grassland ecosystem using one producer, one primary consumer, one secondary consumer, and one tertiary consumer.

4Question

Explain why energy decreases at each trophic level in an ecosystem and describe one consequence of this pattern for food webs.

5Question

A lake ecosystem experiences an increase in phosphorus runoff from nearby agriculture. Predict two likely ecological effects and explain the biological mechanism behind each effect.

Answer Key

#	Answer
1	An ecosystem is a system formed by the interactions of living organisms and their physical environment. Its two main components are biotic factors (living things) and abiotic factors (nonliving things).
2	Possible answers include sunlight, temperature, water, soil type, and humidity. For example, sunlight affects plant growth through photosynthesis, and soil type affects how well plants can absorb nutrients and water.
3	One possible food chain is: grass → grasshopper → frog → snake. Grass is the producer, grasshopper is the primary consumer, frog is the secondary consumer, and snake is the tertiary consumer.
4	Energy decreases at each trophic level because organisms use much of the energy they obtain for life processes such as movement, growth, and respiration, and some energy is lost as heat. One consequence is that food webs usually have fewer organisms at higher trophic levels because less energy is available to support them.
5	Two likely effects are algal blooms and reduced oxygen levels in the water. Extra phosphorus acts as a limiting nutrient, causing rapid algae growth. When the algae die and decompose, decomposers use up dissolved oxygen, which can lead to hypoxia and harm fish and other aquatic organisms.