Unit 3 EcosystemsUnit 3 EcosystemsChapter 6 & 7Chapter 6 & 7

Part 1Part 1The Web Of Life p. 92The Web Of Life p. 92

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Food Relationships p. 93Food Relationships p. 93

Questions #3-9 in the bookQuestions #3-9 in the book

Define Ecosystem

Ecosystem = the network of relationships (interactions) among living (plants, animals) and the non-living parts (soil, climate, water etc.) in an environment.

Differentiate the terms producers, consumers decomposers. P. 93

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.

Differentiate the terms producers, consumers, decomposers. P. 93

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.

Differentiate the terms producers, consumers, decomposers. P. 94

Examples:WormsBacteriaFungiProtozoa

Differentiate the terms food chain & food web. P. 94

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 web is more complex and is composed of several food chains

Food web is a more realistic picture of an ecosystem.

Food Chain vsvs Food Web

Identify ALL examples of each trophic level.

Shrubs, grass, trees

Grasshopper, rabbit, deer, squirrel

Mountain lion, snake, shrew, insect-eating bird, hawk

Hawk, snake, mountain lion

Bacteria, fungi

Producers

Primary Consumers

Secondary Consumers

Tertiary Consumers

Decomposers

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

Draw an example of a food web containing humans. P. 94

MosquitoHawkCow

GrassMan

DecomposerPhytoplankton

Fish

Draw an example of a food web containing humans. P. 94

ManCow

Mosquito

Hawk

Phytoplankton

fish

Grass Decomposer

What happens to energy? (Handout)

What happens to energy?

85-90% is LOST or USED up:

maintaining the organism (Ex. metabolism, reproduction etc.)

And as heat!!!

10-15% is stored:

Available or transferred to other animals when it is eaten.

IF NOT EATEN:

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.

Inorganic nutrients are cycled, energy is not.

Summary – Energy & Food Webs

Question #14, 15 & #16 p. 98 make perfect review questions for the test..