1. Energy Flow in Ecosystems GISAT 112

2. Objectives Define the terms ecosystem and ecology Describe how energy and matter flow in an ecosystem Do calculations to determine the productive efficiencies of an ecosystem Explain the concept of an energy pyramid

3. Ecology Ecology - the study of relationships between organisms and their environment (Greek oikos-house, and logos - study of) Ecosystems - a community of different species interacting with one another and with their nonliving environment of matter and energy The size of an ecosystem is somewhat arbitrary - defined by the area we wish to study.

4. What sustains life on earth? 1) Energy flow from sun 2) Cycling of matter 3) Gravity 6CO 2 + 6H 2 O + solar energy ==> C 6 H 12 O 6 + 6O 2 C 6 H 12 O 6 + 6O 2 ==> 6CO 2 + 6H 2 O + energy

5. Simplified Ecosystems In simplest terms, all ecosystems have 3 basic components: autotrophs (producers) consumers (herbivores, carnivores, and decomposers) abiotic matter Draw these 3 components as the points of a triangle. What interactions occur between them? What crosses the boundaries of the triangle? Can you name these processes?

6. Producer-Consumer Chains Producer-consumer chains (or webs) drive the flow of matter and energy –Producer (autotroph) –Consumer (heterotroph)

10. Primary Production Gross primary production (GPP) is the ability of producers to produce carbon compounds from solar energy. Units are energy per area per time (usually kcal/m 2 /year). Net primary production (NPP), is the amount of energy that remains after accounting for energy used by producers. NPP = GPP – Energy used in respiration

11. Average NPP for Various Ecosystems

12. Secondary Production Not all energy stored in plants is consumed by herbivores—some just can’t be accessed If a herbivore does capture some of the NPP energy, not all of that energy is assimilated into the herbivore’s body. The energy consumed is used for maintenance, growth, and reproduction—or passed as waste. The stored energy is considered secondary production for the next trophic level

13. An Example of Secondary Production Energy Model Ingestion Respiration Waste Production I = P + R + W Assimilation (A) = P + R

14. Production Efficiencies A/I = assimilation efficiency; efficiency of consumer in extracting energy from the food it consumes. P/A = production efficiency; efficiency of consumer in incorporating the assimilated energy into new tissue growth, or secondary production.

15. Food Chains and Energy Flow

16. Energy Flow for a Grassland

17. Energy Pyramids

18. Pyramid of Numbers Pyramid of Biomass

19. Pyramid of Energy Flow

20. Energy needed to support a Cow?

21. 70 14 Growth 1000 Produced 800 Unavailable 130 Waste 56 Respiration Energy Balance of a Cow 200 Consumed