Investigation 4, Part 2Mono Lake Food Web

Warm upWhat is an ecosystem?What is a community?

One of the main points about an ecosystem is the interaction between biotic and abiotic factors.

A community is groups of populations interacting with one another.

Mono LakeOne way the organisms in the Mono Lake system

interact is by eating each other. (Nom, nom….Lunch!)

This is called a feeding relationship.I have sets of cards of important organisms from

Mono Lake.Each card contains:

PhotoCommon and scientific nameLife cycle and population dynamicsHow it gets foodIt’s role in the ecosystem

Mono Lake CardsRead the cards to become familiar with the

organism.Organize the cards, picture side up.Use the arrow strips to show feeding

relationships between the organisms. (Who eats who?)

Every organism should be included in this chart.

If an organism is involved in more than one feeding relationship, indicate that with arrows.

Arrow DirectionDo spiders and flies have a feeding

relationship? Yes

Who gets eaten?The spider eats the fly

Fly Spider

The arrow goes from the fly to the spider even though the spider eats the fly. The arrow represents the energy of the fly going into the spider.

Food ChainIn an ecosystem, many organisms survive by

eating other organisms. The benefits of the food eaten by one

organism can then move to one and then another organism as each one is eaten.

The path that food takes from one to another organism is called a food chain.

Here is one I saw in your groups:Planktonic aglae Brine shrimp

California Gull Coyote

Food WebI saw lots of organisms in your groups that

were connected by more than one arrow. Some organisms like phalaropes eat more

than one organism.Some organisms like brine shrimp are eaten

by many organisms. When you connect all the arrows, the arrows

cross each other in complicated ways. A diagram that shows all the feeding

relationships is called a food web.

Types of OrganismsWhat types of organisms do not eat other

organisms?The two kinds of algae

How do they survive with out eating?All living things need food/energy to survive, so

they must make their own. Organisms that make their own food are

producers. They make food that is consumed in an ecosystem.

In the Mono Lake ecosystem, the producers are algae.

Types of OrganismsProducers like algae make their own food,

but animals like brine shrimp and gulls do not.

How do they get their food?They eat other organisms.

Organisms that eat other organisms are called consumers.

Types of ConsumersConsumers that eat producers are primary

or first-level consumers.Consumers that eat primary or first-level

consumers are secondary of second-level consumers.

Consumers that eat secondary or second-level consumers are tertiary or third-level consumers.

Consumers that eat tertiary or third-level consumers are fourth-level consumers.And so on……..

Another Type of organismSome things never get eaten. They die natural deaths.These dead organisms are broken down and

consumed by microorganisms called decomposers.

Bacteria and fungi are decomposers. Everything that is not eaten by a consumer is

eventually eaten by a decomposer.

Revisit your Food WebThis time show the LEVEL of the organisms

in your web.Producers on the bottom.Primary consumers are the next level up,

etc…

Some are Tricky Red-necked phalaropes

Eat both brine shrimp and brine flies making them secondary consumers.

Also eat planktonic algae making them primary consumers.

California gullsEat mostly brine shrimp and flies.Given the chance will eat eggs and chicks of snowy

plovers and Caspian terns.

How can we show these dual roles on our charts?What about decomposers? How should we show them?

Finish up Lab sheet 21.