Energy Flow Through an Ecosystem

1. Energy Flow Through an Ecosystem

2. Levels of Ecological Organization • Energy flows through these levels

3. Levels of Organization • Species: similar organisms that can produce fertile offspring. • Populations: individuals that are of the same species and live together

4. Q: When does a population grow? • A: When more individuals grow than die r(rate of growth)=birth rate – death rate

5. Communities: Different populations that live together in an area • Ecosystems: All the biotic and abiotic factors of an area. Give an example of a population, community and ecosystem at ETHS

6. Q: Within an ecosystem, can there be unlimited growth of a population? Why or Why not? • A: No, there are not unlimited resources and wastes accumulate • Carrying capacity:The population size that an environment can sustain

7. Energy Flow Through an Ecosystem • Thermodynamics: the study of energy transformations • Law 1: Energy can be transferred and changed but it CANNOT be created nor destroyed. • Energy only flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers) • Sunlight is the main energy source for life on Earth • Inorganic compounds (minerals) can also be energy sources (deep ocean)

8. Trophic Level: classification of an organism based on their source of energy • Energy flows through the different levels of an ecosystem

9. 1st Trophic Level-- Producers • Can harness energy directly from their physical environment (sun) • Transform this energy into chemical energy • used as food, combine or break down molecules, make cells… • Called autotrophs because they can make their own food • Examples: plants, bacteria and some algae

10. 2nd Trophic Level -- Consumers: • Organisms that rely on other organisms for chemical energy • Cannot harness energy directly from their physical environment • Called heterotrophs because they cannot make their own food • Examples: animals, fungi, many bacteria • Q: Do all consumers eat the same thing?

11. Herbivores: • Energy source comes from eating only producers • Also called primary consumers • Examples: cows, caterpillars, ducks, deer

12. 3rd Trophic Level-- secondary consumers • Organisms whose energy source comes from other consumers • Divided into two groups • Omnivores • Carnivores

13. Omnivores: • Eat both consumers and producers • Examples: bears, crows, humans Carnivores: • Only eat other consumers • Considered “meat eaters” • Examples: tigers, snakes, owls, dogs

14. 4th Trophic Level -- Top Carnivores • Carnivores that consume other carnivores • Example: a hawk that eats a snake

15. Detritivores and Decomposers: • Consumers whose energy source comes from waste and dead bodies from organisms of all trophic levels • Cause decay or the break down of molecules • Examples: scavengers, bacteria, fungi Q: Why are detritivores and decomposers useful?

16. Food Chain: Shows only one path of energy flow • Food Web: Shows multiple paths of energy flow

17. Q: What happens to the energy? • Some is stored in the body used later for things like growth • Some is lost in waste • what the body can’t digest or already has enough of • Most leaves as heat • Only about 10% of available energy is actually transferred from one trophic level to the next • as you go up in trophic levels, the amount of useable energy goes down

18. Top Consumers (450 cal) Secondary Consumers (4,500 cal) Primary Consumers (45,000 cal) Producers (450,000 cal) Energy Pyramid Energy is lost One calorie = the amount of energy needed to raise the temp of 1g (1mL) water 1ºC

19. Energy pyramids are NOT drawn based on the # of organisms at that level • Energy pyramids ARE drawn based on biomass and amount of available energy at that level • Biomass = total amount of living tissue, usually referring to what can be used as fuel. • The producers level usually has the most biomass