Transcript CB-Humans in the Biosphere

Humans in the Biosphere
I.
Resources
A. Important terms
1. Renewable resource
a. Can be regenerated if living (tree) or
renewed by biogeochemical cycles if nonliving (freshwater)
b. Must be renewed at a rate equal to or faster
than consumption
c. Solar energy = ultimate renewable resource
2. Nonrenewable resource
a. Cannot be easily renewed by natural
processes
(ex: fossil fuels takes millions of years)
3. Sustainable use – using natural resources at a rate
that will meet the needs of present humans without
harming the needs of future generations
B. Land Resources
1. Used by humans for space for communities
(houses/businesses), raw materials for industry
(minerals/trees), farming, and grazing
2. Problems with overuse:
a. Developing over open space and farmable land
b. Soil erosion caused by strip mining, farming and
overgrazing destroys fertile topsoil
c. Desertification - farming, overgrazing and drought caused by
climate change can turn once productive areas in to desert
Sand dunes encroaching on
Nouakchott
Only 5% of
Lake Chad
remains
 overgrazing
the
surrounding
area has led to
desertification
C. Forest Resources
1. Forests provide oxygen, nutrient storage, food and
habitats for wildlife, climate control and protection
for freshwater supplies
2. Deforestation - logging and agriculture causes
severe erosion, nutrient loss, and other permanent
damage
Virgin forest remaining in the U.S.
NASA satellite observation of forest fires
resulting from Amazon deforestation on August
27 2007. The red dots represent areas of fire.
D. Water Resources
1. Freshwater
a. About 3% of Earth’s water supply is freshwater, but
only about 1% is still drinkable
b. Increase human pop  increase demand for
freshwater
c. Water supply is decreasing due to pollution from:
d. Industrial chemicals, agricultural run-off, waste and
domestic sewage contaminate freshwater supplies
Developing and poor nations will be the most
affected. Increase in conflicts and wars over
freshwater sources projected.
e. Eutrophication
1)
2)
3)

Fertilizers (N and P) run off into freshwater ecosystems
Explosive algal growth
Ecosystem is drained of nutrients and dissolved oxygen
What effect does this have on a lake?
f. Wetlands
1) Transition areas between land and water that are
seasonally covered with water and support
aquatic plants and diverse wildlife
2) Include bogs, marshes, and swamps
3) Important b/c they provide water-storage that
reduces flood intensity, improve water quality by
filtering pollutants, and provide critical habitat for
endangered species
4) Approximately 54% of US wetlands have been
destroyed
The Benefits of Wetlands Movie
2. Ocean resources
a.
b.
c.
d.
Provide a major source of protein  fish
overfishing some species to extinction
governments can make laws to limit fishing
aquaculture = fish/shellfish farms
Catfish
aquaculture
catch
Yellow fin tuna
may be
commercially
extinct in 5 years
if fishing is not
controlled,
experts warn.
Dead wetlands,
destroyed through
shrimp aquaculture.
Wetlands are like rain
forests – they have
many different
species. They are
destroyed to make
shrimp farms.
Companies leave
them after only 3-5
years, leaving the
ecosystem
destroyed.
Amount of Fish per Person
(kilograms)
Total Catch
(million tons)
World Fish Catch
Year
World Fish Catch per Person
Year
E. Air Resources
1. Air polluation
a. Smog = smoke and water vapor
b. Causes increase in human illnesses,
damages plants and man-made materials
c. High temps & low wind = more smog
Sunny day after rain
Sunny day
Ozone Depletion
2.
a.
b.
c.
d.
Ozone is a layer of O3 in atmosphere that
absorbs 97%-99% of biologically harmful UV
radiation emitted by the sun
Since the 1950s, chlorofluorocarbons (CFCs)
used in refrigerants (freon) and propellants
break down ozone in the atmosphere
In the 1970s a hole in the ozone layer
developed over Antarctica
Most CFCs are banned and the ozone layer is
expected to close in the next 50 years
3. Acid Rain
a. Water in the atmosphere mixes with air pollution
and forms acids (H2SO4 and H2NO3)
b. Volcanoes and burning fossil fuels give off pollution
c. Most pollution comes from making electricity
d. Effects of Acid Rain
1) pH of the water changes, which causes fish,
shellfish, coral reefs and other organisms die
Healthy coral
Coral bleaching
2) Damage to forests
3) Damages cars, buildings,
bridges, cultural objects
4.
Global Climate Change
a.
Caused by an increase in the amount of CO2 and
other greenhouse gases in the atmosphere

What are some sources of CO2?
b.
These excess gases warm the surface of the planet
by trapping solar heat in the atmosphere (draw)
sunlight
Some heat escapes into
space
Greenhouse gases trap some heat
atmosphere

What kind of problem can this cause?

Global warming
c.
Global warming = increase in the average temperature of
the biosphere
d. Types of predicted and actual changes
1) Storms become stronger and longer (hurricanes)
2) Drought – very little or no rain
3) Water shortages due to decrease of ice packs
and glaciers
4) Polar ice sheets quickly cracking and melting 
ocean levels are rising  flooding of coastal
regions
5) Fast changes in ecosystems  species extinction
II. Biodiversity
A.
Biodiversity = the variety of all living organisms on Earth
1. So far biologists have identified ~1.5 billion species
B. Why is it important?
1. Improves ecosystem’s health and helps it to
prevent and recover from a variety of disasters
2. Species depend on each for survival
3. Provides humans with a greater variety of
plants to eat, medicines, tourism, etc.
C. Threats to biodiversity
1. Humans hunting species towards extinction
a. extinction = species is gone (died forever)
2. Pollution
3. Habitat destruction
Threats to Biodiversity
4. Invasive species - organisms that move to places
where they do not usually live
a. Reproduce quickly with no natural predators
b. Can hurt individual species and whole ecosystems
c. Ex: zebra mussel in the Great Lakes
5. Biological Magnification
a.
Some chemicals (DDT) and elements (lead and
mercury) cannot be burned or removed with the
organism’s wastes.
b.
They accumulate as you move up the food chain.
D. Conserving Biodiversity
1. Endangered = species in immediate danger of extinction
if conditions don’t change
2. Conservation = wise management of natural resources,
including preservation of habitats and wildlife
3. Best thing to do = focus on protecting entire ecosystems
a. Protects many species at the same time
Biodiversity priorities
4. Main conservation challenge
a. Restrictions on wildlife products  financial hardships
for those with jobs that depend on ecosystem goods
and services
b. Developing countries have difficulties financing
conservation over human survival and needs
III. Sustainability
A.
B.
C.
Limit air pollution
Increase/use public transportation
Use renewable energy sources  wind, hydro, and
solar power
D. Conserve/decrease energy use
E. Reforestation
F. Resource limits (ex: fishing quotas, deforestation, etc.)
G. Protect endangered species
H. Recycle
I. Limit human population growth
J. Buy products labeled “sustainable”
K. Developed nations need help from other nations with
good technology
L. Eat more veggies and less meat