Energy Flow Pyramids and Trophic Levels

Transcription

1 Energy Flow Pyramids and Trophic Levels

2 TROPHIC LEVELS An organisms trophic (feeding) level is determined by the organism s source of energy There are 3 main trophic levels in a food web. 1. Autotrophs 2. Heterotrophs 3. Saprotrophs

3 1. AUTOTROPHS: Capture energy from the sun (photosynthetic) or inorganic molecules (chemosynthetic) and converts it into usable energy. Also known as (AKA) PRODUCERS produces food (make energy storing molecules), Eg. Plants, algae and some kinds of bacteria

4 2. HETEROTROPHS- AKA CONSUMER obtains the energy to build their molecules by consuming plants or other organisms Includes: primary, secondary, tertiary (etc.) consumers, and

5 3. SAPROTROPHS/DECOMPOSERS An organism that gets it s energy by feeding off of dead or decaying organic matter 2 types: Detritivores and Scavengers

6 SCAVANGERS Start the decomposition process by finding large quantities of dead material (like corpses) and breaking it down into smaller pieces. Eg. Hyenas, Crabs, Vultures.

7 DETRITIVORES Organisms that eat detritus, or dead organic matter. Finish the decomposition process by taking the leftovers from scavengers or waste from other organisms and breaking it down to the molecular level. Eg. Fungi, Bacteria, Earth Worms

8 How do you tell the difference between a Scavenger and Detritivore? Scavengers tend to start the decomposition process by turning large pieces of food into smaller one. Detritivores finish the process by breaking the smaller food into molecules that are recycled into the ecosystem. Scavengers are typically larger animals, while Detritvores typically are smaller microorganisms or invertebrates (though fungi can get quite large). Scavengers typically have large ranges that they travel to find corpses. Detritivores typically stay in one general area and eat what ever waste, dead left overs come to them.

9 Energy Pyramid Model Organisms convert food (glucose) into energy. This energy is given off as heat which is lost to space. Energy is a one way path. It is not a cycle.

10 Energy Flow Models: graphs which illustrate the trophic levels in a community.

11 Energy Pyramid Model An energy pyramid is a diagram that compares energy used by producers, primary consumers, and other trophic levels. As a rule each trophic level receives only 10% from the trophic level below. In other words each trophic level loses 90% heat to the atmosphere.

12 Study the food web and convert it into an energy pyramid model. The autotrophs in this food web start off with 123,000 kilojoules of energy and the decomposers are included on the outside of the pyramid. Also label the levels with the terms on paper Student Task

13 Decomposer, Detritivore Saprotrophs Mushrooms, earthworms Carnivore 123 kj 1,230 kj Hawk Red-tailed hawk, Bear, Secondary Consumer Heterotroph, Carnivore 12, 300 kj Marmot, Grouse, Butterfly, Deer, Chipmunk, Bear Primary Consumer Heterotroph, Herbivore flowers, grasses (seeds, berries) Producers Autotrophs 123,000 kj

14 Pyramid of Biomass Biomass is the mass of organisms minus water. Biomass refers to the amount of carbon and other trace elements an organism s body contains.

15 Study the food web below and convert it into a biomass pyramid model. The autotrophs (phytoplankton) in this food web start off with 5,693,112 Kg of biomass. Also label the levels with the terms found on your paper Student Task

16 5,693 kg Whale Student Task Tertiary Consumer, Heterotroph, Elephant Seal, Carnivore Killer Whale 56,931 kg Penguin, Leopard Secondary Consumer, seal, squid, cod Carnivore, heterotroph 569,311 kg Primary consumer, cod, krill, zooplanktonherbivore, heterotroph 5,693,112 kg Phytoplankton Autotrophs, producers

17 Pyramid of Numbers Illustration of the number of organisms at each level

18 How can more people be supported on Earth when there is a limited supply of resources? It depends on what they are eating.

19 EXIT SLIP Explain this graphic- feel free to draw it out. In your answer, make sure to tell me: How much energy did the plant start with? How much energy will go to the crow? Why? Plant material eaten by caterpillar 100 kilocalories (kcal) Feces 50 kcal 35 kcal Cellular respiration What will there be the most of in this ecosystem: plants, caterpillars, or crows? How do you know? 15 kcal Growth