Biology · Form and function

B4.2 — Ecological niches

Biology · SL / HL · syllabus-mapped notes

1. B4.2.1

   Ecological niche as the role of a species in an ecosystem

   Define ecological niche, including the biotic and abiotic interactions and how a species obtains food.

2. B4.2.2

   Differences between organisms that are obligate anaerobes, facultative anaerobes and obligate aerobes

   Distinguish obligate anaerobes, facultative anaerobes and obligate aerobes by oxygen tolerance.

3. B4.2.3

   Photosynthesis as the mode of nutrition in plants, algae and several groups of photosynthetic prokaryotes

   State the three groups that photosynthesize: plants, algae and some prokaryotes.

4. B4.2.4

   Holozoic nutrition in animals

   Explain holozoic nutrition: food ingested, digested internally, absorbed and assimilated.

5. B4.2.5

   Mixotrophic nutrition in some protists

   Explain mixotrophic nutrition using Euglena, distinguishing obligate from facultative mixotrophs.

6. B4.2.6

   Saprotrophic nutrition in some fungi and bacteria

   Explain saprotrophic nutrition in fungi and bacteria, and why they are called decomposers.

7. B4.2.7

   Diversity of nutrition in archaea

   Explain how archaea use light, inorganic chemicals or carbon compounds to produce ATP.

8. B4.2.8

   Relationship between dentition and the diet of omnivorous and herbivorous representative members of the family Hominidae

   Infer diet from dentition in the Hominidae, using human, floresiensis and Paranthropus skulls.

9. B4.2.9

   Adaptations of herbivores for feeding on plants and of plants for resisting herbivory

   Explain herbivore mouthparts, and how plants resist herbivory with structures and toxic compounds.

10. B4.2.10

    Adaptations of predators for finding, catching and killing prey and of prey animals for resisting predation

    Explain chemical, physical and behavioural adaptations in both predators and prey.

11. B4.2.11

    Adaptations of plant form for harvesting light

    Explain six strategies plants use to harvest light in forests.

12. B4.2.12

    Fundamental and realized niches

    Distinguish fundamental niche (potential) from realized niche (actual, under competition).

13. B4.2.13

    Competitive exclusion and the uniqueness of ecological niches

    Explain competitive exclusion, including both outcomes: elimination, or restriction of both species.