Unit 3 Ecosystems

Ecosystem Ecosystem - the network of relationships among plants, animals and the non-living parts in an environment.

Other examples: Grasses Trees shrubs Water lilies Flowers Vegetables Fruits Producer - a plant which can synthesize carbohydrates using carbon dioxide and the sun’s energy. Actually “produce” their own food and food for the rest of the ecosystem.

Consumers = All those organisms that have to eat (consume) plants or animals to obtain their food.

Types of consumers Primary Consumers: Animals that eat producers. Also called 1st. order consumers. (Ex. Rabbit, squirrels, grouse, insects) Secondary Consumers: Animals that eat primary consumers. Also called 2nd. order consumers. (fox, owl, mink ) Tertiary Consumers: Animals that eat secondary consumers. Also called 3rd. order consumers. (Wolf, coyote, hawk)

Examples: Worms Bacteria Fungi Protozoa Decomposers = Simple organisms that obtain their food from dead/decaying organisms and wastes.

Consumers, producers & decomposers…. Similarities All three are terms referring to the way organisms obtain food & energy Differences The way they obtain food Producers make it, Consumers eat it, Decomposer feed on wastes & dead material.

Food chain - linear sequence representing the nutrition of various species from the simplest plant to the top carnivore. Food web - a series of interconnecting food chains in an ecosystem.

Food Chain vs Food Web

Similarity Both food chains and food webs show the flow of nutrients and energy in an ecosystem. Difference Food web is more complex Food web is composed of several food chains Food web is a more realistic picture of an ecosystem.

Identify examples of producers & consumers and decomposers. Primary Consumers Secondary Consumers Tertiary Consumers Decomposers Shrubs, grass, trees Grasshopper, rabbit, deer, squirrel Mountain lion, snake, shrew, insect-eating bird, hawk Hawk, snake, mountain lion Bacteria, fungi

Give an example of a food chain from fig. 6.4. P. 95 Tree → insect insect eating bird hawk Producer Primary consumer 2nd order consumer 3rd order consumer Note: The arrows indicate the flow of energy & nutrients from one level to the next

Sample Food Chain

What happens to energy at each level? 10-15% is stored and: Is available or transferred to other animals when it is eaten. 85-90% is LOST or USED up: in maintaining the organism (Ex. metabolism, reproduction etc.) And as heat!!! IF NOT EATEN: This energy is transferred to the decomposers.

What happens to the energy at the decomposer level? Same thing….ALMOST !? Most is lost or used up through heat and maintaining the organism. If eaten (Ex. A mushroom) energy gets passed on. HOWEVER, once a decomposer dies…. The energy is LOST FOREVER!!!

Summary – Energy & Food Webs The ultimate source of energy (for most ecosystems) is the sun. The ultimate fate of energy in ecosystems is for it to be lost as heat, metabolism, reproduction, etc.. Energy and nutrients are passed from organism to organism through the food chain as one organism eats another. Decomposers remove the last energy from the remains of organisms.

Summary – Energy & Food Webs