Energy Flow in Ecosystems

1. Energy Flow in Ecosystems Chapter 5

2. Why do organisms need energy? • Basic body processes (breathing, digestion, blood flow) • Migration/moving • Catching food • “energy flow determines how much life an ecosystem can support”

3. Sunlight • The main source of energy for all life on Earth • Only 1% of the sun’s radiation is used by organisms

4. Energy Catchers • Autotrophs = plants, algae, and bacteria that capture energy for food from sunlight or chemicals • also called Producers • “essential to the flow of energy in an ecosystem”

5. Photosynthesis • The process by which autotrophs capture the energy of the sun • Convert carbon dioxideand water into oxygen and carbohydrates • Remove CO2 from the atmosphere and add Oxygen for us to breathe

6. Chemosynthesis • Process by which organisms convert chemicals to energy w/o light • Many types of bacteria do it • Able to live in harsh environments (tar pits, deep sea vents, hot springs, salt marshes)

7. Consumers • Consumers = organisms that cannot harness energy directly from the environment and must require it from eating other organisms • also called Heterotrophs

8. Types of Consumers • Herbivores = eat only plants (cows, deer) • Carnivores = only eat animals (snakes, owls)

9. Types of Consumers • Omnivores = eat both plants and animals (humans, bear, crows) • Detrivores (decomposer) = feed on dead and decaying plants and animals – detritus (snails, crabs, bacteria)

10. How do organisms use the energy they get from food? • Cellular Respiration = the cellular process that converts food into energy • sugar and oxygen are converted into carbon dioxide and water and a lot of energy is released

11. Feeding Relationships • Energy flows through an ecosystem in one direction • Sun/Inorganic Molecule to Autotroph (producer) to Heterotroph (consumer) • Modeled as a food chain or food web

12. Food Chain • A series of steps where energy is transferred from organisms being eaten or by eating • Energy flows in one direction • Some start or end with decomposers

13. Food Webs • Energy relationships are more complex than a simple food chain • A producer can be eaten by more than one consumer (grass is eaten by deer, rabbits, and mice in a forest) • Depicts all the feeding relationships in a specific ecosystem

15. Trophic Levels • The name for each step in the food chain • Producer = 1st level • Consumers = 2nd, 3rd, 4th, etc… • Each consumer depends on the level below it for energy

16. Energy Pyramid • Shows how much energy is stored and how much is used at each trophic level • 90% used = reproduction, move, breathe, etc… • 10% stored = available for next consumer • Less energy at the top