Ecosystems
This lesson covers:
- Defining ecosystems
- Biotic and abiotic factors that affect ecosystems
- Examples of specific biotic and abiotic factors
Defining ecosystems
Ecology is the study of the relationships between organisms and their environment.
An ecosystem consists of all the living things in a specific area, along with the non-living, physical components they interact with.
The size of ecosystems can range widely, from small microbial communities to the entire biosphere encompassing the planet. The scope of an ecosystem studied by scientists is determined by their research focus, which might be an isolated environment like a tidepool or a broader area such as a meadow.
Biotic and abiotic factors that affect ecosystems
Ecosystems are subject to constant change, influenced by both living and non-living elements.
These can be categorised as:
- Biotic factors - The living parts of an ecosystem.
- Abiotic factors - The non-living, physical parts of an ecosystem.
Biotic factors
The interactions between living organisms within an ecosystem can significantly influence its balance.
Examples of biotic factors:
- The numbers and types of plants and animals.
- Competition among organisms for essentials such as food, territory, and mates.
- The dynamics of predator and prey relationships.
- The role of diseases and parasites within the ecosystem.
Abiotic factors
The non-living components of an ecosystem, or abiotic factors, play a crucial role in shaping the structure of an ecosystem, the interactions between its organisms, and its overall stability over time.
| Abiotic factor | Why it affects ecosystems | Influence on ecosystems |
|---|---|---|
| Light intensity | Influences the growth and behaviour of photosynthetic organisms as light is required for photosynthesis | In low light, photosynthetic organisms may develop larger leaves or use pigments adapted to low light conditions, while organisms that cannot adapt may die |
| Temperature | Affects the activity of enzymes that regulate metabolic and reproductive activities | In warm conditions, plants and ectothermic animals may develop faster, and changes can trigger migration and/or hibernation in animals, and dormancy and/or leaf fall in plants |
| Water availability | Critical for most cellular activities, for maintaining cellular osmotic balance, and for photosynthesis | Lack of water can lead to drought stress, cellular damage, wilting in plants, and reduced photosynthesis rates that can lead to death |
| Oxygen availability | Vital for the survival of aerobic organisms as they need it to release energy | Low oxygen can lead to suffocation of aerobic organisms, especially those in slow-moving water or waterlogged soils |
| Soil type (edaphic factors) | Influences the soil's drainage capabilities and the nutrients it can offer to organisms | Different soil types, such as sand, loam, and clay, have different particle sizes, which affects their drainage properties and the types of organisms they can support |