Transcript Biodiversity, Succession and Resources

Biodiversity, Succession and
Resources
Ecology Day 4
BIODIVERSITY
• Degree to
which species
VARY within
an ecosystem
• Which of these
has more
biodiversity?
WHY IS BIODIVERSITY SO
IMPORTANT?
• The Back-up plan:
• “Backup” orgs if one species dies due
to disease, there is one to fill the niche
• Maintains stable ecosystem:
• If lots of orgs, every niche can be filled!
Therefore, stable ecosystem!
• Benefits Humans!:
• Ensures a variety of genetic material
• Vast rainforests may hold cures,
medicines and other useful resources!
HOW DO HUMANS REDUCE
BIODIVERSITY?
1. DEFORESTATION:
•
•
Destruction of forests
IMPACT: Forces many orgs to find new homes
•
If cannot adapt, will become extinct
2. OVER HUNTING:
•
When bounties offered for a certain species, it can
become over hunted
•
•
EX: LION
IMPACT: With such a drastic drop, will affect
pop’ns of other animals
•
EX: DEER POP’N ROSE B/C NO LIONS; DEER
OVERGRAZED AND STARVED THEMSELVES
HOW DO HUMANS REDUCE
BIODIVERSITY?
3. Clearing land for farming and space:
•
•
Replacing a diverse ecosystem with one or
two crops 
IMPACT: Taking away resources for
ourselves and other species
4. DIRECT HARVESTING:
•
•
Taking species out of natural habitat for our
benefit (wanting unusual pets or plants)
IMPACT: We are reducing the # of those
species in their natural habitat
HOW DO HUMANS REDUCE
BIODIVERSITY?
5. IMPORTED SPECIES :
•
•
When a species is imported and released
into a new environment
IMPACT: New species may adapt well and
drive out existing species
•
•
EX: Rabbits in Australia
IMPACT: New species often become pests
because they have NO NATURAL
PREDATORS
•
EX: Zebra mussels in NY waterways
What is Ecological Succession?
• A series of changes by which one
habitat naturally changes into another
• PROCESS:
• Starts with simple habitat w/ little diversity
• CLIMAX COMMUNITY:
• A stable diverse habitat (ex. Forest)
• Will be reached if climate remains stable over a
number of years
When does Succession occur?
1. When environment becomes suitable for
another community:
• Grasses grow in shallow soil, but add
nutrients as they live and die
• Soil then becomes suitable for shrubs
• Shrubs shade out the grasses and take
over
• Over time, shrubs will be shaded out by
trees
2. When natural disasters occur that alter stable
ecosystems
• Fires, overgrazing, etc…….
• Altered ecosystems will need many
successions to recover
Stage 1: Bare Bedrock
Bare
Bedrock
Stage 2: Lichens grow
Bare
Bedrock
Bedrock
With
Lichens
Stage 3: Mosses grow
Bare
Bedrock
Bedrock
With
Lichens
Bedrock
With
Mosses
Stage 4: Grasses grow
Bare
Bedrock
Bedrock
With
Lichens
Bedrock
With
Mosses
Grasses
Stage 5: Shrubs and small trees
Bare
Bedrock
Bedrock
With
Lichens
Trees
And
Shrubs
Bedrock
With
Mosses
Grasses
Stage 6: Climax Forest (100 – 200
years of without disturbance)
Bedrock
With
Lichens
Bare
Bedrock
Trees
And
Shrubs
Bedrock
With
Mosses
Climax
Forest
Grasses
Succession can also happen in a
lake!
Lake
Habitat
Erosion
causes
buildup of
Organic
debris in
lake
Lake fills in
becoming
shallower
and
eventually
becomes a
swamp
Filling in
continues
an
eventually
a climax
forest
results
What resources can we use over
and over again?
• RENEWABLE RESOURCES
• Can be replaced naturally
• Still need to be used carefully
• EX: Fish are renewable but over harvesting
and damaging env. can inhibit renewal
• Can you name some renewable
resources?
• Water, food, solar energy
What resources do we use that
cannot be replaced?
• NONRENEWABLE RESOURCES
• Decisions we make today affect what our future
will have
• Most things we use are being depleted due to
industrialization and technology
• Can you list some nonrenewable resources?
• Fossil fuels (oil + natural gas), minerals
• PRESERVATION = The 3 R’s
REDUCE
REUSE
RECYCLE