86. Competition & Interdependence

GCSE Biology - Competition & Interdependence

Ecology is the study of how organisms interact with each other and their environment. These relationships are complex and interconnected, meaning a change in one part of an ecosystem often has knock-on effects for others.

1. Key Ecological Terms

Understanding the hierarchy of an environment is the first step in ecology:

• Habitat: The specific place where an organism lives (e.g., a field or a basement).

• Population: All the individuals of the same species living in a specific habitat.

• Community: All the different populations of various species living together in a habitat.

• Ecosystem: The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.

2. Competition

Resources in any environment are limited, which leads to competition between organisms. This can occur between members of the same species or different species.

What Animals Compete For:

• Food: Essential for energy and growth.

• Water: Necessary for biological processes.

• Territory (Space): Required for hunting, nesting, and safety.

• Mates: Crucial for reproduction and passing on genes.

What Plants Compete For:

• Light: Required for photosynthesis.

• Space: Needed for roots to spread and leaves to capture sunlight.

• Water: Absorbed from the soil for structure and photosynthesis.

• Mineral Ions: Nutrient chemicals taken from the soil for healthy growth.

3. Interdependence

Interdependence is the idea that all species within a community rely on each other for survival. If one species is removed or its population changes, it can shift the balance of the entire ecosystem.

Examples of Interdependence:

• Plants produce food by photosynthesis.

• Animals eat plants (herbivores) or other animals (carnivores).

• Animals pollinate plants or disperse their seeds.

• Decomposers break down waste, returning nutrients to the soil.

Predicting Changes (Food Webs)

Using a food web, you can predict how a change in one population affects others. For example:

• If the mouse population increases: They eat more grass, leaving less for rabbits. This could cause the rabbit population to fall.

• Impact on Predators: Predators like hawks might have more mice to eat, but if the rabbit population (their other food source) drops, the overall impact on the hawk population might be neutralized.

Summary Table: Ecological Factors