Food Chains Food Webs and Energy Flow Pages

Food Chains, Food Webs and Energy Flow Pages 63 -73 Objectives: Students will: A)Define 7 words related to food webs and energy flow. B) Compare energy flow and nutrient cycling in an ecosystem. C) Summarize the relationship between producers, consumers, and decomposers in a food chain/web. D) Summarize the energy flow at each trophic level in a food chain/web

Obj. A) Define 7 words related to food webs and energy flow Autotroph or Ability to produce organic material Producer (food) from inorganic chemicals and some source of energy (photosynthesis) 6 CO 2 + Heterotroph or Consumer 6 H 2 O C 6 H 12 O 6 + 6 O 2 Consumes organic matter or food from the environment. Turns it into energy through respiration. C 6 H 12 O 6 + 6 O 2 6 H 2 O + 6 CO 2 + 36 ATP Decomposer Breaks down and obtains energy from dead organic matter

Obj. A) Define 7 words related to food webs and energy flow Food Chain Movement of energy and nutrients from one feeding group of organisms to another in a series that begins with plants and stops with carnivores and decomposers Food Web Interlocking pattern formed by a series of interconnecting food chains Trophic Level Functional classification of organisms by feeding relationships Shows amounts Energy of energy at each Pyramid trophic level of a food chain or web

B) Compare energy flow and nutrient cycling in an ecosystem. Energy Flow vs. Nutrient Cycling Energy flows through ecosystems – • 1. Enter via sunlight • 2. Stored temporarily in complex molecules and used for LIFE PROCESSES. • 3. The rest leaves in the form of HEAT. Nutrients recycle within ecosystems – • 1. They are atoms or molecules (Water, Carbon, Nitrogen, Phosphorous…) that stay within the ecosystem • 2. They are found at different times in different parts of the system. • 3. This is the law of conservation of matter. Matter is never created or destroyed, it is simply rearranged. They are recycled.

Sample Nutrient Cycle More on these later. The Carbon Cycle

C) Summarize the relationship between producers, consumers, and decomposers in a food chain/web. D) Summarize the energy flow at each trophic level in a food chain/web What happens to the level of energy as you move through each trophic level? Energy Pyramids and Food Chains Why do you think this happens? Energy Pyramid Shows the relative amount of energy available at each _____level. Organisms Answer these on your notes, then trophic place your answers on an exit ticket. use about _______ percent of What percent of the energy transfers 10 this energy for ____ life from one trophic level to the next? _____. processes The rest is lost as For what two things is the other 90% ________. heat used?

C) Summarize the relationship between producers, consumers, and decomposers in a food chain/web. D) Summarize the energy flow at each trophic level in a food chain/web Food Chains Energy is transferred in a system from one organism to another. This transfer of energy from organism to organism makes up a food chain. Each level of consumption is called a trophic level. Primary producers are therefore in the first trophic level. 4. Trophic Level 4 = who are eaten by… you get the idea. 3. Trophic Level 3 = who are eaten by the secondary which trophic level is theconsumers (Carnivores) At highest level of energy found? Trophic 2 =it. Next come level? the primary consumers Why 2. do you. Level think is this (Herbivores) 1. Trophic Level 1 = Photosynthetic producers which range from single-celled bacteria to redwood trees.

C) Summarize the relationship between producers, consumers, and decomposers in a food chain/web. D) Summarize the energy flow at each trophic level in a food chain/web Most of the sun’s energy is reflected or absorbed by the atmosphere or Earth’s surface. 1% of the energy sent by the Sun is available to life on Earth. Of this energy, 3% is trapped by green plants or algae. All life on Earth is therefore due to the 0. 03% of the energy absorbed from the Sun. All life depends upon energy and each trophic level above the first trophic level gets energy from consuming lower trophic level organisms. Only about 10% of the energy from one trophic level can get to the next one through consumption. The rest of the energy is lost as heat.

C) Summarize the relationship between producers, consumers, and decomposers in a food chain/web. D) Summarize the energy flow at each trophic level in a food chain/web Energy and the Food Chain If 10% of the energy can be transferred from one trophic level to the one above it, each trophic level must have 10 x the energy as the one above it. The number of trophic levels depends upon the number of primary producers in the first trophic level. Biomes with small numbers of primary producers have short food chains. Why? In this diagram, which trophic level receives the lowest amount of energy? Predict what would happen to this food chain if there was a large decrease in the number of mice.

C) Summarize the relationship between producers, consumers, and decomposers in a food chain/web. D) Summarize the energy flow at each trophic level in a food chain/web What is a food web? A combination of interconnecting food chains Most animals at higher trophic levels occupy several trophic levels simultaneously because of variation in their diets.

C) Summarize the relationship between producers, consumers, and decomposers in a food chain/web. D) Summarize the energy flow at each trophic level in a food chain/web The stability of an ecosystem depends on its number of producers and decomposers. Why are decomposers important to an ecosystem’s stability? Once all organisms die, they are broken down into nutrients that are put back into the soil to feed producers. Why are producers important to an ecosystem’s stability? They are the 1 st trophic level. Every level above it depends on them. Lots of producers = big food web.

Identify producers, 1 2 3 & 4 Understanding Check A Food Web in the Arctic Tundra consumers in this food web 1. 1. A snowy owl, that eats a vole that eats plants is what? 2. 2. An arctic fox that eats a Longspur that eats insects that eat plants is what? 3. 3. The caribou? 4. 4. The arctic fox that eats the ptarmigan that eats a wolf spider that eats insects that eats Which is it? Producer 1 st Level Consumer 2 nd Level Consumer plants. 3 rd Level Consumer 4 th Level Consumer

Understanding Check Questions 1. 2. 3. 4. 5. What are the two most important categories when it comes to the stability of a food web? Why are the two that you identified in #1 so important? What percentage of energy transfers from one trophic level to the next? Identify the two reasons energy is lost as you move up an energy pyramid. What happens to nutrients in an ecosystem?