IB Biology HL B4.2 Ecological Niches Questions
Practise IB Biology HL B4.2 with population and community data questions on interactions, biodiversity, ecological change and sustainability.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Practise IB Biology HL B4.2 with population and community data questions on interactions, biodiversity, ecological change and sustainability.
Explain the concept of an ecological niche.
(ecological niche is) mode of existence/role of an organism within its ecosystem
(ecological niche includes) its habitat/abiotic factors of the environment
(ecological niche includes) what the species eats / how the species obtains food
(ecological niche includes) interactions with other species
(ecological niche includes) the set of all ranges of limiting factors an organism tolerates
Distinguish between fundamental niches and realized niches.
fundamental niche is the niche for which a species has adaptations for success/potential mode of existence whereas a realized niche of a species is its actual mode of existence
the realized niche is often smaller than the fundamental niche (of a species)
competition/predation is reason for the differences (between fundamental and realized niches)
A student set up a 20 -metre transect line along a rocky shore and measured the abundance of seven species of seaweeds (A-G) at 21 different sampling stations at fixed distances. The kite diagram represents the species abundance data across the 20 metres.
Seaweeds are obligate aerobes. Describe an environmental condition required for seaweed survival.
oxygen;
There is evidence that prokaryotes were responsible for changes in the atmospheric gases 3.5 billion years ago. Outline the role of bacteria in producing an oxygen-rich atmosphere.
early prokaryotes were anaerobic/did not require oxygen
population increased / shortage of food
photosynthetic bacteria/cyanobacteria evolved
produced/released oxygen (into the atmosphere)
by splitting water molecules/photolysis/photosynthesis
concentration of oxygen built up over time / conditions changed from reducing to oxidizing