4. Objectives
SWBAT define biodiversity
SWBAT predict the impact of various environmental changes based on the amount
of biodiversity in an ecosystem
SWBAT establish a relationship between the amount of biodiversity in an ecosystem
and the likelihood of extinction of a species in that ecosystem
SWBAT describe invasive species and their impact on an ecosystem’s biodiversity.
SWBAT define and describe extinction.
SWBAT predict the effects of certain environmental factors on an ecosystem’s
biodiversity.
7. High vs. Low Biodiversity
Ecosystems with high biodiversity have many
different species of organisms.
Ecosystems with low biodiversity do not have
many different species of organisms.
15. Ecosystem Stability
The higher the biodiversity, the more
stable the ecosystem (stable= stays
the same)
An ecosystem with high biodiversity does
not change easily; it is stable
An ecosystem with low biodiversity is
unstable
One small change could cause many species
to die
20. Higher Biodiversity
A disturbance hits…
A drought happens and kills all the grass.
Grass
Rabbit
Foxes
Chickens
Lettuce
21. Higher 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 have a major impact!
23. CFU 1: Which ecosystem has
higher biodiversity?
Ecosystem 1
Ecosystem 2
24. CFU 2: Which ecosystem would be
more affected by a disease that
killed all the rats?
Ecosystem 1
Ecosystem 2
25. CFU 3: Which ecosystem is more
stable? Why?
Ecosystem 1
Ecosystem 2
26. Ecosystem 1
Ecosystem 2
CFU 4: What might happen to the snakes in Ecosystem
2 if there are not any of that species of snakes anywhere
else in the world and most of the rats in the ecosystem
die from disease?
27. Biodiversity and Extinction
Environmental change in an ecosystem with
low biodiversity can even cause extinction of
a species
Can occur if there are no organisms of that
species in other ecosystems throughout the world
Species with specialized diets (low
surrounding biodiversity) and specific
habitats are more likely to become extinct
than species with diverse diets and a wide
range of habitats
28. Invasive Species
Invasive species are non-native species of
organisms in an ecosystem that reproduce quickly
and have few natural predators
Native= originally from that ecosystem
Non-native= originally from somewhere else
Invasive species decrease biodiversity in an
ecosystem by taking over food and space from native
species
Decrease the number of native species
Invasive species are very harmful to ecosystems that
already have low biodiversity
30. CFU 5
Brown tree snakes are a species of snakes
that were imported to the island of Guam from
South America. Brown tree snakes eat many
different types of birds and lizards. They
reproduce rapidly and have few natural
predators. What will most likely happen to the
number of native bird and lizard species on
Guam over time?
31. CFU 6
Does an invasive species
normally increase or decrease
biodiversity in an ecosystem?
32. Zebra Mussel Reading and
Questions
Options for reading:
Whole class
Small groups
Partners
Individually
37. Biomes Jigsaws
7 groups
Each group will be assigned a biome reading.
You must identify the following factors for your
biomes:
Presentation: After 15 minutes, each group will
present major features of their assigned
biome. The rest of the class will fill in their
graphic organizers accordingly.
