Energy Flow

1. Energy Flow From the Sun, Through an Ecosystem, Into Heat

2. Autotrophs / Producers • Auto = Self-made • example: Automatic, Automobile • Troph = Eater / Food • Example: trophy (prizes in competitions used to be food!) • So, AUTOTROPHS make their own food. They produce their own food. • How? Photosynthesis!!!!

3. Heterotrophs / Consumers • Hetero = different Troph = food • Heterotrophs CANNOT make their own food, so they must eat other organism. They consume other animals. • Heterotrophs are ALL organisms that eat other organisms • They are herbivores, carnivores, omnivores, and detrivores. ALL of these animals cannot make their own food, and must eat other organisms (including plants) FOR food!

4. Decomposers • DECOMPOSERS are heterotrophs that eat dead things and in the process return nutrients to the soil. • DECOMPOSERS are always DETRIVORES • Detrivore specifies that they eat dead things • Decomposer specifies that they break down dead things and return nutrients to the soil • What are some examples of DECOMPOSERS?

5. DECOMPOSERS • Bacteria • Fungi • Flies • Maggots • Hyenas • Dung Beetles • Worms • Mold

6. Primary, Secondary, Tertiary • Primary Consumers eat Autotrophs (plants) • Secondary Consumers eat Primary Consumers • Tertiary Consumers eat Secondary Consumers

7. Pop Questions Are all consumers meat-eaters? NO! Herbivores are consumers too Are carnivores ever primary consumers? NO! But, omnivores can be Are herbivores always primary consumers? YES!

8. Trophic Levels • Each step in the chain represents a TROPHIC LEVEL • A trophic level is an feeding step in the passage of energy and materials through an ecosystem

10. Energy Flow • Energy enters the ecosystem as Sunlight • Sunlight is the One + Only + Ultimate energy source • It is turned into food by autotroph (plants) • However, plants only capture 1% of total sun / energy • Plants use this energy to grow, to reproduce, to move (a little), and to keep themselves alive • Overall, plants use 90% of energy this way! • So, only 10% of energy is passed on to the next trophic level (whatever eats the plant)

11. 10% Rule • At every level, 90% of the energy received from food is used to keep the organism alive. • For example, a zebra who eats grass only gets 10% of the energy from grass that the grass got from the sun. • Then, the lion who eat the zebra only gets 10% of the energy from the zebra that the zebra got from the grass. • This makes sense! THE ZEBRA USES ENERGY RUNNING AWAY FROM THE LION!!

13. Energy Pyramid

14. Pop Question!

15. The same holds true with Biomass • Biomass: Total amount of living tissue within a given trophic level (I am ___ lbs of human biomass) • Just like an energy pyramid, BIOMASS decreases as you go up trophic levels. • And, the 10% Rule applies! • Energy is mass!

16. So, how much grass does it take you to survive? Meat Eater: Vegetarian: Human  Vegetables  Sun 150lbs x 10 (veggies) 1500 lbs • Human  Cow  Grass  Sun • 150lbs x 10 (cow) x 10 (grass) • 15,000 lbs It’s better for the earth to be a vegetarian. Except… You may not be getting enough PROTEIN!

18. Ok, let’s see how we’re doing • First, put a P (producer) or a C (consumer) next to the animals • Now, put a O (omnivore), H (herbivore), or C (carnivore) next to the animals too. • Now draw an energy pyramid (up to Tertiary Consumer) using any of those animals.