Communities

• An ecosystem is the interaction between a community of living organisms and their environment
• A community consists of all the organisms that live in a habitat (plants and animals)
• An ecosystem consists of two or more populations of organisms in their environment
• Levels of organisation within an ecosystem:
• Producer: plants and algae that photosynthesise
• Primary consumer: herbivores that eat producers
• Secondary consumer: carnivores that eat primary consumers
• Tertiary consumer: carnivores that eat secondary consumers
• Interdependence in an ecosystem:
• All organisms in an ecosystem depend on each other for survival
• If the population of one organism changes, it can affect the rest of the ecosystem
• Small changes in ecosystems can have large consequences
• Competition in an ecosystem:
• Plants and algae compete for light, space, water, and minerals
• Animals compete for food, mates, and territory
• Organisms with more resources tend to grow healthily and have more offspring
• Competition can be interspecific or intraspecific
• Stable communities:
• A stable community has populations of all species remaining relatively constant over time
• Populations are in a healthy balance with their environment