Functioning ecosystems and succession — Question 26

26a)

$\mathrm{T}\mathrm{r}\mathrm{a}\mathrm{n}\mathrm{s}\mathrm{f}\mathrm{e}\mathrm{r}\,\mathrm{e}\mathrm{f}\mathrm{f}\mathrm{i}\mathrm{c}\mathrm{i}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{y}\,\,$

$=\,(1700/16\,000)\,\mathrm{x}\,100\%\,$

$=\,11\%\,$

• determines transfer efficiency [1 mark]

• provides appropriate working [1 mark]

26b)

$\mathrm{E}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\,\mathrm{l}\mathrm{o}\mathrm{s}\mathrm{t}\,\mathrm{t}\mathrm{o}\,\mathrm{d}\mathrm{e}\mathrm{c}\mathrm{o}\mathrm{m}\mathrm{p}\mathrm{o}\mathrm{s}\mathrm{e}\mathrm{r}\mathrm{s}\,\,$

$=\,92\,000\,–\,(55\,000\,+\,16\,000)\,$

$=\,21\,000\,\mathrm{k}\mathrm{J}\,\mathrm{m}^{–2}\,\mathrm{y}\mathrm{e}\mathrm{a}\mathrm{r}^{–1}\,$

• determines 21 000 [1 mark]

• provides appropriate working [1 mark]

26c)

Primary producers convert solar energy into chemical energy in the form of glucose through photosynthesis. At each level of the food chain some chemical energy is transformed into heat energy as organisms use it to drive their biochemical processes (respiration).

• describes one way energy is transformed [1 mark]

• describes a second way energy is transformed [1 mark]