Food Chains and Food Webs SNC 1 P

Food Chains and Food Webs SNC 1 P Findlay

Learning Goals and Success Criteria • I will investigate the characteristics and interactions of biotic and abiotic components of a terrestrial or aquatic ecosystem. • I can describe the importance of these components in a sustainable ecosystem.

Sustainable Ecosystems • Do you like to play games? – If you do, you will need energy. Every time you run or jump, you are using up energy in your body. • How do you get the energy to play? – You get energy from the food you eat. – Similarly, all living things get energy from their food so that they can move and grow. – As food passes through the body, some of it is digested. This process of digestion releases energy.

Biological Levels of Organization Life can be organized into different levels. Individual Population Community Ecosystem

Biotic Components of an Ecosystem • Producers – make their own food – Plants are producers – They make their own food through a process called photosynthesis – Also called autotrophs • Consumers – eat other organisms to gain energy (cannot make their own food) – Also called heterotrophs

Consumers • Organisms that depend on other organisms for their food are called consumers. • Consumers can be classified based on what they eat: – Herbivores - eat plants only – Carnivores – eat animals only – Omnivores - eat both plants and animals

Consumers • Which type of consumer is each of the following organism? omnivore herbivore carnivore

Consumers • Do you know why there are more herbivores than carnivores? – Energy is passed from one organism to another. When an organism eats, only a fraction of the energy becomes new body mass; the rest of the energy is released as waste or used up. – When a carnivore eats, only a small amount of energy is available.

Decomposers • Organisms that break down dead plant and animal matter, or waste. – E. g. micro organisms (bacteria) • Why are decomposers important to an ecosystem? – They prevent dead matter from building up. – Allow nutrients to return to soil for other plants to use and grow.

Scavengers • Organisms that eat animals that are already dead. • E. g. vultures, hyenas

Food Chains • Organisms depend upon other organisms for food. This interaction makes a food chain. • A food chain is a step-by-step sequence of who eats who.

Food Chains • All food chains must start with a producer. Why? – Only producers can make their own food.

Classifying Consumers • Although consumers can be classified as herbivores, omnivores, or carnivores, they can also be classified based on how far they are from the producer. • The consumer that eats the producer is called a primary consumer. • The consumer that eats the primary consumer is called a secondary consumer. • The consumer that eats the secondary consumer is called a tertiary consumer.

Classifying Consumers

Classifying Consumers • Classify the following organisms in the food chain below: producer → primary consumer → secondary consumer → tertiary consumer

Classifying Consumers 5 th Trophic Level 4 th Trophic Level 3 rd Trophic Level 2 nd Trophic Level 1 st Trophic Level

Food Webs • A set of interconnected food chains. • Identify 3 different food chains in this food web, label the tropic levels, classify the consumers and decide if each organism is an autotroph or a heterotroph.