Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A scientist cuts the plants of a patch of a meadow in two seasons. In the dry season, the fresh plants weigh and of that is water. In the wet season, the fresh plants weigh and of that is water.
The trophic levels are T1 producers, T2 primary consumers, T3 secondary consumers and T4 tertiary consumers. In a web, a species can sit on more than one level. The standing crop is the biomass or the number of organisms in a unit area, and dry weight is the more accurate measure.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Patch . Dry season: , water. Wet season: , water.
Plan. Find the fresh mass for each square metre, then keep the part that is not water.
Step 1. (a) fresh. dry.
Step 2. (b) fresh. dry.
Step 3. (c) The fresh masses are different, but the dry masses are equal. The extra weight of the wet season was only water. Dry weight is the more accurate measure of the biomass.
Answer: ; ; dry weight is more accurate.
Check. The plants did not change, so equal dry masses are what we should expect.
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