Biodiversity and Ecosystem Stability

1. Which organism will have the lowest energy? Explain how you know.

2. Which organism will have the highest biomass? Explain how you know.

3. If the blue bird consumes 100 J of energy, how much energy will the eagle be able to get from eating the blue bird?

4. CHALLENGE! If the grass provided 367 J of energy, how much energy will the blue bird get? What about the eagle that eats the bird?

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 Evolution Test Class Averages Homework Review – We got it! What is biodiversity? Ecosystem stability Stations Exit Question

Evolution test class averages

2: 72.63:

67.94: 66.0

47 - 91

29 - 100

27 - 93

Homework Review

5. Which of the following statements are true?a. The energy content of the

iguana depends on the energy content of the rabbit

b. The energy content of the bird is transferred to the snail

c. The energy content of the eagle depends on the energy content of the iguana

d. All of the above are true

Homework Review

6. A forest fire kills all the snails in the area.

The number of birds will… (circle one)

go extinct OR increase OR decrease OR no change

7. A group of raccoons enter the ecosystem and

eat all the worms. The number of iguanas will…

go extinct OR increase OR decrease OR no change

8. The animal is most directly impacted by a change in the population of eagles is the…

iguana OR plants OR worm OR snail

Homework Review

16. Which group of organisms will you expect to have the largest biomass? Explain your reasoning.

17. Using your answer from above, which group of organisms will you expect to have the largest amount of energy? Make sure to explain the link between energy and biomass.

18. If a worm consumes 247 Joules of energy, how much energy will the Iguana receive when it eats the worm?

Animal PopulationEagle 4Iguana 400Worm 15,000

Biodiversity Definition

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

LowBiodiversity

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 Preserves ecosystem stability

Ecosystem stability… What?

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

Ms. S, show me another way to write that! Key Point #2: High biodiversity

= stable ecosystem, low biodiversity = unstable ecosystem CHANGE!

Lots of species die UnstableMost species don’t change Stable

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 BIODIVERSITYLet’s try this idea out…

Ms. S shoots all the bears in two forests. In the first forest, everything dies as a result. In the second forest, a couple of animals die, but things remain mostly the same. Which has higher biodiversity?Which is more stable?

Stations (GP)

Practice your new knowledge! 6 stations 7 minutes for each station

THINK about what you’re reading and what you’re drawing. Really. Think. Seriously.

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 QuestionsAnswer BOTH in complete sentencesRead 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.