IB Biology HL 4.2.14 Restrictions on trophic levels Question Bank

Practise IB Biology HL 4.2.14 by analysing why high-trophic-level animals are large but few in number.

Exam points

Analyse energy and biomass constraints on populations at the highest trophic level.
Evaluate how trophic efficiency explains body size and small population numbers.

[Maximum number: 3]

The image shows an example of a soil food web.

Figure for Question C4.2.14—Restrictions on trophic levels question 1 — IB Biology HL

Explain the reasons for food chains rarely containing more than four or five trophic levels.

a. energy is lost between the trophic levels;

b. transfer between levels is only usually 10\% efficient

OR

energy transformations take place in living organisms / the process is never 100\% efficient;

c. energy is lost by the organism/used in respiration/ released as heat/movement;

d. energy is lost as waste/feces/urine/undigested food/uneaten parts;

e. as energy is lost between trophic levels and so (higher ones) have less biomass / less biomass available for next level;

$3 \max$

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C4.2.14—Restrictions on trophic levels question 1