Ecology: Feeding Relationships

Feeding Relationships in Ecology

• Organisms must have energy to perform the seven life processes.
• Producers like plants create nourishment.
• Consumers that do not produce their own nourishment rely on other organisms for energy.

Types of Consumers

• Consumers includes herbivores, carnivores, omnivores, and decomposers.
• Herbivores eat only plants.
  • Examples include male buffalo weighing up to 850 kg.
  • The eland, standing 1.6m tall from foot to shoulder.
  • Elephants with a 22-month gestation.
  • The white rhino, with about 18,000 remaining.
• Carnivores eat other animals and include predators like leopards and lions.
  • Also insectivores like the aardwolf and chameleons.
  • Scavengers such as vultures, jackals, crows, and hyenas consume dead animal material.
• Omnivores eat both plants and animals.
  • Examples are baboons, vervet monkeys, warthogs and humans.
• Decomposers break down dead plants and animals, recycling nutrients into the soil.
  • Maggots, dung beetles, earthworms, and fungi are decomposers.

Energy Flow in an Ecosystem

• Energy flows from one organism to another in an ecosystem.
• Plants and algae use photosynthesis to make their own food from sunlight.
• Energy moves along a food chain from a producer (plant) to a consumer.
• Decomposers can be the last link in a food chain.
  • For example, mushrooms break down dead plant and animal matter.

Food Chains

• Food chains show how energy moves between organisms.
• A food chain includes:
  • A producer.
  • A primary consumer which eats the producer.
  • A secondary consumer which eats the primary consumer.
  • A tertiary consumer which eats the secondary consumer.
• Trophic levels include:
  • Producer = level 1.
  • Primary consumer = level 2.
  • Secondary consumer = level 3.
  • Tertiary consumer = level 4.
• Arrows show the flow of energy.
• Food chains can be represented as pyramids.
  • The base is producers.
  • Higher levels (primary, secondary, tertiary) have less energy.

Energy Transfer

• Organisms use 90% of food energy for cell respiration.
• Only 10% goes to the next level.
• If a plant makes 10,000 joules, 1,000 joules move to level 2.
• To calculate energy transfer, level energy is multiplied by 0.1 (10%).
  • Energy is measured in joules (J).

Food Webs

• Food webs link numerous food chains.
• Webs always start with a producer.
• Example prompt: "Identify a food chain with four trophic levels".
  • An example of a 4 organism chain is: tree -> deer -> snake -> eagle.
• An example of a 3 level chain is: grass -> mouse -> snake (or eagle).