Question 19M.3.HL.TZ2.16
| Date | May 2019 | Marks available | [Maximum mark: 5] | Reference code | 19M.3.HL.TZ2.16 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Explain, Outline | Question number | 16 | Adapted from | N/A |
Explain the factors that can contribute to the exponential growth phase in a sigmoid population curve.
[3]
a. ideal environment/unlimited resources/below carrying capacity ✔
b. little disease/few predators ✔
c. high natality/birth rate AND immigration ✔ Both needed.
d. natality and immigration greater than mortality and emigration ✔
The vast majority of candidates could provide part of an explanation; most mentioned resources, but for many the effect of natality, mortality, immigration and emigration (both not well distinguished for some) was obscure.
Outline the effect of carrying capacity on the growth of a population.
[2]
a. carrying capacity is maximum population size/number of individuals that environment can support
OR
carrying capacity varies with abundance of limiting resources ✔
b. population growth slows/fluctuates as the carrying capacity of environment reached ✔
Most candidates had an idea about carrying capacity, but there was only one element in the outline of many.