2.8.1Additional lessons
Habitats — IB Biology SL Revision Notes & Topical Questions
5 min read 5 parts Lesson 41 of 142
Part 1 of 5What a Habitat Is
Habitat
- Habitat The place where an organism lives, which provides food, shelter and the conditions it needs to survive.
Location
- Location A habitat can be described by geography, for example a polar habitat at the North or South Pole.
Ecosystem type
- Ecosystem type Habitats can also be named by their type, such as grassland, desert, wetland or rainforest.
Many species
- Many species Any one habitat contains many different species that together make up a community.
Microhabitat
- Microhabitat A small, specific part of a habitat, such as the underside of a stone, can have its own conditions.
Part 2 of 5Levels of Organisation
1
An individual organism is a single living thing of one species.
2
A population is a group of organisms of the same species living in the same area at the same time.
3
A community is all the populations of different species living and interacting in one habitat.
4
An ecosystem is a community together with the non-living environment it interacts with.
5
Many ecosystems with similar climates and vegetation make up a biome.
Part 3 of 5Describing a Habitat
Describing a Habitat
Abiotic features
- Abiotic features Temperature, light, water, soil and salinity vary between habitats and affect which species can live there.
Biotic features
- Biotic features Other organisms provide food, competition, predation and shelter within the habitat.
Example: rocky shore
- Example: rocky shore Species on a rocky shore live in zones that are covered and uncovered by the tide.
Example: pond
- Example: pond A pond is a freshwater habitat with plants, invertebrates, fish and microbes in one community.
Part 4 of 5Why Habitats Matter
Why Habitats Matter
Resources
- Resources The conditions in a habitat decide which food, shelter and breeding sites are available to a species.
Change
- Change Loss or damage of a habitat, for example by deforestation, reduces the size of populations living there.
Conservation
- Conservation Protecting a habitat protects the whole community of species that depend on it.
Part 5 of 5Exam Checklist & Tips
2.8.1 – Key Points for the Exam
- Habitat The environment in which a species normally lives.
- Population A group of organisms of one species living in the same area.
- Community All the populations of different species in an area, interacting together.
- Ecosystem A community and its non-living environment, interacting as a system.
Common Mistakes
- Using habitat and ecosystem as if they mean the same thing;
- an ecosystem includes the interactions with abiotic factors.
- Calling all the organisms in an area a population, when a population refers to a single species.
- Describing a habitat only by its location and ignoring the ecosystem type.
- Thinking that a habitat contains only one species; habitats contain communities.
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