Question 18M.3.HL.TZ1.17
| Date | May 2018 | Marks available | [Maximum mark: 5] | Reference code | 18M.3.HL.TZ1.17 |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Explain, State, Suggest | Question number | 17 | Adapted from | N/A |
In 1911, twenty-five reindeer (Rangifer tarandus) were introduced onto Saint Paul Island in Alaska and the population was recorded for 40 years.
State the type of growth of this population up to 1940.
[1]
exponential «population growth»
Suggest one possible cause for the decrease of the number of animals after 1940.
[1]
lack of food / disease / hunting / increase of predators
Explain biogeographic factors that increase the effectiveness of nature reserves.
[3]
a. large area can support greater range of habitats / longer food chains / higher population numbers
b. low edge effect with circular reserves
OR
reduced edge effect minimises area that is disturbed/competition
c. intact / unbroken areas represent less disturbance on habitats
d. fragmented areas linked by corridors
e. (proximity of fragmented areas) allows for animal movement / genetic exchange
