Definition
Habitat
A habitat is the physical location where a species lives and interacts with its environment.
- It includes all the abiotic (non-living) and biotic (living) factors essential for the species' survival, growth, and reproduction.
- Every species has its own habitat range, determined by its adaptations, tolerances, and ecological requirements.
Note
- A habitat is not just a physical space.
- It is a dynamic environment that supports life.
Key Characteristics of a Habitat
- Each habitat has distinct climatic, physical, and biological conditions.
- Organisms within a habitat have adaptations that allow them to survive in those conditions.
- Habitats can be terrestrial (land-based) or aquatic (water-based).
- Within one ecosystem, there can be multiple habitats, each supporting unique species.
Example
- In a tropical rainforest ecosystem, different habitats exist.
- The canopy for birds and insects, the forest floor for decomposers and small mammals, and tree trunks for epiphytes and fungi.
Types of Habitat
- Habitats can vary widely depending on environmental conditions and location.
- They can be classified as:
- Terrestrial Habitats: Land-based environments such as forests, grasslands, deserts, tundra, and mountains.
- Aquatic Habitats: Freshwater (lakes, rivers, wetlands) and marine (oceans, coral reefs, estuaries) ecosystems.
- Microhabitats: Small or specialized areas within larger habitats (e.g., under logs, within leaf litter, inside tree bark).
Analogy
- A habitat functions like a “complete survival toolkit”.
- It provides all essentials (food, water, space, and mates) for species to live and reproduce.
Components of a Habitat
1. Geographical Location
- Refers to the range or distribution of the habitat on Earth.
- Influenced by latitude, longitude, altitude, and regional climate.
- Determines biome type (e.g., rainforest vs tundra).
Example
The African elephant (Loxodonta africana) has a wide geographical range found across savannahs, forests, deserts, and marshes in sub-Saharan Africa.
2. Physical Conditions
- The non-living (abiotic) features that define a habitat’s suitability.
- Includes temperature, water availability, salinity, pH, sunlight, and soil composition.
- Species evolve adaptations to tolerate or exploit these conditions.
Example
The saguaro cactus (Carnegiea gigantea) thrives in the Sonoran Desert (USA/Mexico), with:
- Thick, pleated stems for water storage.
- Waxy cuticle to reduce evaporation.
- Shallow, widespread roots to absorb rainfall rapidly.
3. Biotic Components
- Include all living organisms within the habitat that affect survival:
- Predators and prey relationships.
- Pollinators and seed dispersers.
- Competitors for resources.
- The interdependence of these biotic components maintains ecological balance.
4. Resource Availability
- Every species requires specific resources such as:
- Food and nutrients
- Water and air
- Space or territory
- Shelter or nesting sites
- The quantity and quality of these resources determine habitat suitability and carrying capacity.
Theory of Knowledge
- How does our understanding of habitats influence conservation efforts?
- Should we prioritize protecting habitats or focus on individual species?
Self review
- Define what is meant by a habitat and give two examples.
- Explain how physical conditions influence the habitat of a species.
