Biodiversity and Ecosystem Stability 1. Where does all energy in the food web begin? 2. Name the producer 3. 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?

Food Webs YARN

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 Foxes How 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.