DP Biology (last assessment 2024)
Question 18M.3.SL.TZ1.13
| Date | May 2018 | Marks available | [Maximum mark: 4] | Reference code | 18M.3.SL.TZ1.13 |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Distinguish, Outline | Question number | 13 | Adapted from | N/A |
13.
[Maximum mark: 4]
18M.3.SL.TZ1.13
(a)
Distinguish between fundamental niche and realized niche.
[1]
Markscheme
fundamental is the potential (niche) and realized is the actual (niche)
OWTTE.
(b)
Outline the impact of competition on the niche of an organism.
[2]
Markscheme
a. competition can limit the niche
b. competition can limit resources
c. when competition is removed the niche can expand
d. can result in exclusion or removal of a species from a niche / only one species can occupy a niche
(c)
Outline the characteristics of keystone species in an ecosystem.
[1]
Markscheme
a. keystone species has a strong/disproportionate effect on a community/food web/ecosystem
b. absence of keystone species would completely alter the ecosystem