Food Chains, Food Webs, and Ecological Pyramids

Ecosystems involve energy flow primarily from plants to animals.

• Producers (Autotrophs): Create their own food through photosynthesis, forming the base of the food chain (e.g., green leaves, carrots).

• Consumers (Heterotrophs): Can't produce their own food and are divided into multiple levels:

  • Primary consumers: Herbivores that eat producers (e.g., rabbits).

  • Secondary consumers: Carnivores that eat primary consumers (e.g., foxes).

  • Tertiary consumers: Carnivores that eat other carnivores (e.g., hawks).

• Decomposers: Break down dead organisms and recycle nutrients (e.g., bacteria, fungi).

• Food webs show complex interrelations among species, unlike simple food chains that illustrate linear energy flow.

• Energy transfer is inefficient, typically losing 90% at each trophic level (e.g., 10,000 calories at base reduces to 1,000 at top).

• Human activities disrupt these ecosystems, impacting food webs and species relationships.