Ch 18-Intro to ECOLOGY Energy Flow, Food Webs & Ecology Pyramids
All ENERGY on Earth depends on the SUN
How does Energy flow through an Ecosystem? Answer: It moves in one direction from the sun to autotrophs to heterotrophs. That is it is NOT CYLICAL!
A Closer look at Feeding Relationships 1.Food Chain: a diagram showing who eats whom in an ecosystem Ex. Direction of feeding > **The arrow goes INTO The Organism EATING IT!
Types of Organisms in Food Chains Producers/autotrophs- photosynthetic organisms that produce/supply the energy for an ecosystem Ex -grass Flowers Photosynthetic algae Consumers/heterotrophs- organisms that need to eat other organisms to survive-they consume the producers Ex- deer Rat Wolf spider
Types of Consumers/Heterotrophs Primary consumers= herbivores Secondary consumers = small carnivores Tertiary consumers= large carnivores/ omnivores
2. Food Webs: Many Interconnected food chains in an ecosystem. Ex. Producers Primary Consumers [Secondary Consumers] [Top-level Consumers] Secondary consumers Tertiary Consumers
Ecological Pyramids Ecology pyramids show food chains/webs in a different way! Trophic Levels: A feeding level in a food chain. Helps traces Energy in food chains 3 Types 1.Energy Pyramid 2.Biomass Pyramid 3.Species Number Pyramid
1- ENERGY Pyramid 4 Levels 100 % of Sun’s Energy is absorbed > 10% of 1000 passed on 90% of 1000 used by organism 10% of 100 passed on 10% of 10 passed on ONLY 10% of energy from previous level is passed on
2. Biomass Pyramid: Traces how much total mass a living thing contributes to its environment kg of rice 500 kg of mice 50 kg of snakes 5 kg of hawks Trophic Levels 1. Producers 2. Primary Consumers 3. Secondary Consumers 4. Tertiary/Top Consumers Which trophic level contributes the most mass?_____________ Producers
3. Species Number Pyramid: traces how many organisms each trophic level. 1 million acres of grass 100,000 field mice 10,000 snakes 1000 hawks Trophic Levels 1. Producers 2. Primary Consumers 3. Secondary Consumers 4. Top Consumers
Food Chain 1