Ecosystems: Populations and Interactions

Ecosystems: Populations, Communities, and Interactions

• Ecosystems: Systems of interacting living organisms (biotic factors) and non-living components (abiotic factors) in a specific area
• Population: Group of individuals of the same species in the same geographic area
• Community: Group of populations interacting in a shared area
• Ecosystem definition: A community interacting with its abiotic environment
• Interspecific interaction: Interactions between populations of different species, including competition, symbiosis, and predator-prey relationships.

Food Chains and Food Webs

• Predators and Prey: Animals that eat other organisms are predators, and those eaten are prey - forming predator-prey relationships.
• Food Chains: A series of predator-prey relationships that link organisms together and flow in a chain in the transfer of nutrition
• Food Webs: A complex interconnection of food chains; many animals eat a variety of foods
• Producers: Organisms (plants) that synthesize their own food from inorganic matter
• Consumers: Organisms that consume producers or other consumers
• Trophic Levels: Levels based on the intake of nutrition in a food chain/web
  • Primary consumers (herbivores)
  • Secondary consumers
  • Tertiary consumers
  • Quaternary consumers
  • Quinary consumers

Food Chains in Different Environments

• Land Food Chains: Begin with plants as producers, followed by herbivores (primary consumers), then carnivores (secondary/tertiary/etc.), with apex predators at higher trophic levels
• Soil Food Chains: Fallen leaves and roots act as producers, consumed by primary consumers (e.g., earthworms), then secondary consumers.
• Water Food Chains: Algae (producers) are eaten by primary consumers (plankton, shellfish), which are eaten by secondary consumers (fish, starfish).

Food Chain Dynamics

• Species Survival: Plant and animal populations can exist and survive despite being prey because of their abundance and high reproductive capacity
• Apex Predators: Predatory animals at the top of the food chain, though their populations don't grow infinitely, facing environmental resistance due to factors like decreased prey, disease, or reproductive limitations.