User interface language: English | Español

Date May 2018 Marks available 1 Reference code 18M.3.HL.TZ2.16
Level Higher level Paper Paper 3 Time zone Time zone 2
Command term State Question number 16 Adapted from N/A

Question

The model describes the fundamental and realized niches of a species of microscopic marine arthropod in the Northern hemisphere with respect to two different factors (X and Y). The abundance of the species is shown over twelve months. The fundamental niche is separated into five zones ranging from critical to optimal conditions. The population of the species in its realized niche each month is represented by an oval. The size of each oval shows the population abundance.

Distinguish between fundamental niche and realized niche.

[1]
a.

State the month where the population reaches its maximum.

[1]
b.

Outline how factor Y affects the species from January to April.

[2]
c.i.

Suggest, with a reason, what factor Y could be.

[2]
c.ii.

Markscheme

fundamental niche is all potential conditions a species could live in whereas realized niche is actual conditions under which the species live

a.

April

b.

a. limited effect on low/stable population size from January to March
OWTTE
.

b. large effect increases population size from March to April 
OWTTE.

c. niche conditions decrease from January to March 

d. niche conditions improve from March to April

c.i.

a. factor 
eg temperature.

b. explanation
eg as temperature increases in spring «March to April» so the conditions for the species are more favourable.

c.ii.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.i.
[N/A]
c.ii.

Syllabus sections

Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics) » C.1 Species and communities
Show 44 related questions
Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics)
Option C: Ecology and conservation

View options