Students learn the difference between biotic (living) and abiotic (non-living) factors, how each affects where organisms live and how many there are, and which instruments are used to measure abiotic factors. They then use quadrat data to estimate a population size and explain how to make field sampling reliable.
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Curriculum: Texas grade levels (TEKS). We show specific outcome codes only where they have been verified against the official curriculum document.
Completed: Biotic and Abiotic Factors in Ecosystems
7th Grade students (typically ages 12–13) working on ecosystems & food chains. It is pitched at level 2 · standard.
Yes. The PDF includes a full answer sheet with model answers and success criteria where there is more than one good answer. You can also view the answers online.
About 35 minutes for 14 questions. Short, regular sessions work best: two or three a week beats one long one.
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Try Relationships in Ecosystems: Competition, Predation and Symbiosis.
Success TutoringWorksheets7th Grade · Science · Ecosystems & Food ChainsName
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Biotic = living. Abiotic = non-living.
Circle biotic or abiotic.
An ecosystem is made up of all the organisms in an area together with their non-living surroundings.
Biotic factors are the living parts of an ecosystem and their effects: food sources, predators, competitors, parasites and disease. Abiotic factors are the non-living parts: light, temperature, water, wind, soil type, soil pH and saltiness.
Both kinds of factor affect where an organism can live (its distribution) and how many there are (its population size).
Show your working.
It is usually impossible to count every plant in a large area, so ecologists take samples. A quadrat is a square frame, often 1 m × 1 m, placed on the ground. The organisms inside it are counted.
Estimated population = mean number per quadrat × (total area ÷ area of one quadrat).
Field study: A class wanted to estimate how many clover plants grow in a grassy field with an area of 200 m². They placed a 1 m × 1 m quadrat at five random spots and counted the clover plants inside each one.
Quadrat 1: 4 · Quadrat 2: 6 · Quadrat 3: 3 · Quadrat 4: 7 · Quadrat 5: 5
Preview — the PDF contains the full resource and answer sheet.
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Worksheet · 5th Grade · Ecosystems & Food Chains · Level 2 · Standard
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