Unit 1 Chapter 2 Living and Non-Living Things in Ecosystems Section – Food Chains, Food Webs, Nutrient Cycles and the Transfer of Energy Slide Show #6

Producers & Consumers (Review) ▪ Producers  Green plants, algae, and some micro- organisms produce their own food through photosynthesis. ▪ Photosynthesis:  Carbon dioxide + Water --> Starch + Oxygen  In words, when plants take in carbon dioxide and water (in the presence of the sun), they produce starch (food) and oxygen.

Photosynthesis

Producers & Consumers (Review) ▪ Consumers  All organisms that take in food by consuming other organisms.  There are different levels of consumers: – Primary consumers (only eat producers) – Secondary consumers (eat producers and/or primary consumers) – Tertiary consumers (eat producers, primary and/or secondary consumers)

Food Chains The arrow means “is eaten by” or “goes into”. The insect is eaten by the frog. ▪ Food Chains  The movement of food energy in an ecosystem from producers through the different levels of consumers. 5

Food Chain

This is a beach food chain Can you describe what is happening?

Can you show a different food chain? Label each trophic level – include arrows and decomposers

Match the words and phrases. A food chain shows Most food chains start with Plants are Animals are Animals that hunt and eat others are called Animals that are caught and eaten are called producers consumers predators prey a green plant what is eaten by what

Food Webs & Nutrient Cycle ▪ Food webs  Two or more intertwining food chains combine to form a network called a food web. ▪ Nutrient Cycle  Decomposers are also a part of food chains/webs. They breakdown dead organisms to put nutrients back in the soil.  The decomposers are the reason why we never run out of nutrients. Food Web

Can you show a different food web? Draw three food chains and then show inter-linkages Tertiary Consumers Secondary Consumers Primary Consumers Producers Food Chain 1Food Chain 2 Food Chain 3

Nutrient Cycles (Review) Producers uptake nutrients from the soil and store those nutrients in the plant tissue. Nutrients are passed through food chains and webs as consumers obtain nutrients from the food they eat and store those nutrients in their bodies or release it as feces. Decomposers break down and return nutrients from dead organisms and feces to the soil.

Nutrient Cycles (Cont.) Draw a and label nutrient cycle for a boreal forest ecosystem in Newfoundland. Include producers, primary, secondary and tertiary consumers, and decomposers.

Energy flow The energy in any food web initially comes from the sun. It is converted into food energy by plants and is then passed on to each level of consumer. No new energy is added to the web. At each level energy is used up carrying out life functions. Other energy is lost to the environment as heat. 14

At each level in a food web approximately 90% of the energy gets used up or lost as heat. Leaving only 10% to be passed on to the next level. Energy Pyramid 15

Remember : Energy Pyramids do not always indicate the exact amount of food energy required, but are simple generalizations. To model energy flow. Many factors may influence energy flow Draw Your Own Energy Pyramid below. Label each level Energy Pyramid (cont.) 16

Energy pyramids usually have no more than four to five levels. Why? Complete Activity 2-3B to figure out. Energy Pyramid (cont.) 17

Assignment 2 (Part C): Complete questions 1 – 6 page 59 Complete questions 1 – 5, 7 page 63 Chapter 2 Assign Questions 18