Interactions and Ecological Pyramids SNC1P - Ecology

Recall: Energy Flow Producers convert carbon dioxide and water into oxygen and sugar with the help of the sun through PHOTOSYNTHESIS. Most organisms convert the energy stored in chemical compounds into usable energy through CELLULAR RESPIRATION.  CO2 Carbon Dioxide + H2O Water Sunlight  Glucose (Sugar) O2 Oxygen Glucose (Sugar)  +  O2 Oxygen   CO2 Carbon Dioxide  H2O Water Energy 

Recall: Interactions Kingfisher Pondweed Insect larvae Minnow Arrange the following organisms into a possible food chain. Label the producer/consumer and trophic levels. Kingfisher Pondweed Insect larvae Minnow

Recall: Interactions Examine the food web shown. What will happen to the number of clown fish if the sharks become vegetarian? What effect will this have on the number of zooplankton? What will happen to the Blue Regal fish if a disease wipes out the small invertebrates?

Pyramid of Numbers Food chains and food webs show the feeding relationships in a community. But they do not tell us how many living organisms are involved. It takes many plants to feed a herbivore, and many herbivores to feed one carnivore.

Pyramid of Numbers Fox Rabbit Grass Grass

More Practice Draw the following two pyramids of numbers. A small area in Africa is observed to have 20 large plants, 3 antelopes and 1 lion. On the coral reef, there are 25 great white sharks. These 25 sharks feed on 1,100 clown fish. The clown fish feed on 15,000 algae.

What would be a better way of showing the flow of energy? Pyramid of Numbers A pyramid of numbers may not always look like a pyramid. Oak Tree  Aphid  Ladybug  Ladybug Parasites What would be a better way of showing the flow of energy?

Pyramid of Biomass These show the TOTAL DRY MASS of the organisms at each trophic level. They are always pyramid shaped. Parasites Ladybird Aphids Oak Tree

Pyramid of Biomass Biomass is the mass of material in living organisms. Ultimately all biomass is built up using energy from the Sun. Biomass is often measured as the dry mass of biological material in grams. The biomass made by plants is passed on through food chains or food webs. It goes into the animals that eat the plants. The amount of biomass at each stage of a food chain is less than it was at the previous stage.

More Practice Develop a pyramid of biomass based on the pyramid of numbers and mass values below. Mass of one Hawk: 2500 g Mass of one Snake: 130 g Mass of one Mouse: 50 g Mass of one Insect: 0.5 g Mass of one Blade of Grass: 0.2 g

More Practice What is happening to the biomass as we go up the food chain? What is happening to the energy as we go up the food chain?

Pyramid of Energy Most of the energy that enters a trophic level is used by the organism to stay alive. 10% of the energy consumed is stored in the body. 90% of the energy consumed is lost to waste, movement, warmth, and metabolism. Create a pyramid of energy based on the following information: Grass captures 67 000 000 J of energy from the Sun. Rabbits eat the grass, and snakes eat the rabbits. The wolf preys on rabbits and snakes.

Summary The amounts of biomass and energy contained in living things always gets less at each stage of a food chain, from producers onwards. Biomass is lost as waste products and used to release energy in respiration. This is used for movement and to control body temperature. Only a small amount is used for growth.