Biodiversity and Ecosystem Stability

1. Where does all energy in the food web begin?

2. Name the producer3. Name two primary

consumers.4. What would happen to

the population size of bluebirds if the snails were wiped out by a disease?

Objectives

By the end of today, all SWBAT…

Explain why biodiversity is essential to the survival of organisms using food web models

Agenda

Catalyst Review Homework Review What is biodiversity? Ecosystem stability Stations Exit Question

Homework Review

Biodiversity Definition

Biodiversity = number of different species that live in an ecosystem Low biodiversity: few species High: many species

Low Biodiversity

High Biodiversity

Low or High Biodiversity?

Low or High Biodiversity?

Low or High Biodiversity?

Low or High Biodiversity?

Low or High Biodiversity?

Benefits of Biodiversity

Key Point #1: There are three main benefits to biodiversity Many people find nature beautiful Provides medicines—many plants contain treatments/cures for illnesses

Preserves ecosystem stability

Ecosystem stability… What that is!? Stable = things stay the same

Key Point #2: High biodiversity = stable ecosystem, low biodiversity = unstable ecosystem If an ecosystem is unstable, one small

change could cause many species to die If an ecosystem is stable, it does not

change easily

This food web has low biodiversity

Rabbits eat grass. Foxes eat rabbits

Grass

Rabbit

Foxes

This food web has low biodiversity A disturbance hits…A drought happens and kills all the grass.

Grass

Rabbit

Foxes

This food web has low biodiversity What happens to the foxes?

Grass

Rabbit

FoxesHow many species do we have left?

0!BIG change?

This food web has high biodiversity

Let’s add a few more species to our original ecosystem

Grass

Rabbit

Foxes

Chickens

Lettuce

This food web has high biodiversity A disturbance hits…A drought happens and kills all the grass.

Grass

Rabbit

Foxes

Chickens

Lettuce

This food web has high biodiversity What happens to the foxes?

Population size decreases… a little

BIG change?

Grass

Rabbit

Foxes

Chickens

Lettuce

The food web started with high biodiversity

High biodiversity = stable ecosystem One change… didn’t really do anything!

Comparing Multiple Ecosystems Key Point #3: If we have two

ecosystems, the one that CHANGES LESS is the one with HIGHER BIODIVERSITY Mr. J shoots all the bears in two forests. In

the first forest, everything dies as a result. In the second forest, a couple animals die, but things remain mostly the same.

Which has higher biodiversity? Which is more stable?

Stations (GP)

Designed to get you moving, and practice understanding some of what we’ve been talking about 6 stations Each asks you to complete something THINK. About what you’re reading and what

you’re drawing. Really. Think. Work hard. Talk when you’re finished, not

before.

Stations Review (GP)

Any questions?

Closing

There are three primary benefits to biodiversity Beautiful, medicines, ecosystem stability

An ecosystem is stable if it does not change easily when disturbed “Change” = number of species that live there

We can figure out which of two ecosystems has higher biodiversity based on how stable each one is More stable = higher biodiversity Less stable = lower biodiversity

Exit Questions: Answer ALL

Read the passage at right to answer the questions below:

How does trawling affect coral reef biodiversity?

Would the coral reef be more or less stable after trawling? Explain why, and be SPECIFIC.

(Hint: describe what happens to all the organisms in the coral reef ecosystem, and use the word “biodiversity.”)

Read the passage at right to answer the questions below:

How does trawling affect coral reef biodiversity?

Would the coral reef be more or less stable after trawling? Explain why, and be SPECIFIC.

(Hint: describe what happens to all the organisms in the coral reef ecosystem, and use the word “biodiversity.”)

Many organisms live in coral reefs, such as plankton and algae, hundreds of species of fish, sea urchins, and eels. All of these organisms depend on the coral to survive: they live inside of it, use it for shelter, eat it, etc.

Trawling is the process of dragging a gigantic rake across the bottom of the ocean floor to scoop up organisms. This is a very good way to catch fish, but has the unfortunate side effect of destroying nearly all the coral in the trawler’s path.

Many organisms live in coral reefs, such as plankton and algae, hundreds of species of fish, sea urchins, and eels. All of these organisms depend on the coral to survive: they live inside of it, use it for shelter, eat it, etc.

Trawling is the process of dragging a gigantic rake across the bottom of the ocean floor to scoop up organisms. This is a very good way to catch fish, but has the unfortunate side effect of destroying nearly all the coral in the trawler’s path.