Brainlag PlusRandom quadrats, transects, population estimates, capture-recapture and efficiency of biomass transfer.
From a few squares to a whole field
- five 1 m² quadrats: 3, 5, 4, 6, 2 daisies
- mean = 20 ÷ 5 = 4 per m²
- field of 500 m²: about 4 × 500 = 2000 daisies
Place quadrats at random coordinates to avoid bias. Use a transect (quadrats along a line) to see how a species changes from one place to another.
population ≈ (number marked × number caught second time) ÷ number marked in the second catch
efficiency = biomass at the next level ÷ biomass at this level × 100
The rest of this lesson and its 9 practice questions are in Plus.
Screen 1 of 1, free to read.
- 9 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards