Unit 3 Ecosystems

Ecosystem

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

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.

Other examples:GrassesTrees shrubsWater liliesFlowersVegetablesFruits

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)

• Decomposers = Simple organisms that obtain their food from dead/decaying organisms and wastes.

Examples:WormsBacteriaFungiProtozoa

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 & consumersand decomposers.

Producers

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

Note: The arrows indicate the flow of energy & nutrients from one level to the next

Tree→

insect→

insect eating bird →

hawk

Producer Primary consumer

2nd order consumer

3rd order consumer

Sample Food Chain

What happens to energy at each level?

85-90% is LOST or USED up:in maintaining the organism (Ex. metabolism, reproduction etc.)And as heat!!!

10-15% is stored and:Is available or transferred to other animals when it is eaten.

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 WebsThe 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