Transcript Chapter 6 Humans in the Biosphere 2016x

HUMANS IN THE
BIOSPHERE AND
SUSTAINABILITY
HOW HAVE HUMANS
CHANGED THE EARTH?
HUNTING AND GATHERING
 Overhunting and poaching can put animal populations
at risk of extinction.
 over-hunting led to a severe overkill of whale populations, and
to endangerment of 5 whale species .
AGRICULTURE
 Challenges for the future
 Although modern agriculture has increased world food supplies,
it has also created ecological challenges.
 Use of farm chemicals (fertilizers and pesticides) can damage
beneficial insects, contaminate water supplies, and accumulate
in the environment.
 Farm machinery also burns many fossil fuels.
 Finding enough water for irrigation is another problem, because
we are using water faster than the water cycle can replenish it.
INDUSTRIAL GROWTH
AND URBAN DEVELOPMENT
The impact of humans on the
biosphere was transformed
by the Industrial Revolution
during the 1800s.
INDUSTRIAL GROWTH AND URBAN
DEVELOPMENT
 Also, dense human
communities produce lots of
wastes that, if not disposed
of properly, can affect air,
water, and soil resources
which impacts surrounding
ecosystems.
 AND energy production
requires burning fossil fuels
which also impacts air
quality and global climate.
EARTH’S RESOURCES
 Ecosystem goods and services
are classified as either
renewable or nonrenewable.
 Renewable resources- can be
replaced or regenerated if they are
consumed.
 Ex: wind, trees and forests, fisheries,
air, land and fresh water
 If a resource is renewable does that
mean the resource is unlimited?
 No, if it’s consumed faster than it can
be replaced the resource will be used
up.
EARTH’S RESOURCES
 In order to protect our renewable resources we must
limit their consumption.
 Sustainable development- is a way to use these
natural resources at a rate that does not deplete
them.
 Ex: when forests are logged, new trees are planted in
place of the harvested trees.
 This ensures the resources of the forest are not lost.
EARTH’S RESOURCES
 Nonrenewable resourcescan not be replenished or
replaced by the Earth’s
natural processes within a
reasonable amount of
time.
 Ex: fossil fuels- oil ,coal,
natural gas
HOW DO HUMAN ACTIVITIES
AFFECT NATURAL RESOURCES?
Soil erosion
Desertification
Deforestation
Overfishing
Pollution
Acid Rain
Ozone Depletion
SOIL EROSION
 Protecting our resources:
 Land/ soil is a resource that
provides raw materials for
industry, soil to grow crops in,
and space for cities to develop
on.
 Soil erosion- the wearing away
of the surface soil by wind and
water.
DESERTIFICATION
 Caused by a combination
of farming, drought, and
overdrawing groundwater
 Roughly 40 % of Earth’s
land is considered at risk
for desertification.
 This map shows
vulnerable areas in North
and South America.
DEFORESTATION
 Loss of trees/forest
 What happens if there
are no trees or roots?
(why is vegetation
important?)
 SOIL EROSION, soil is
exposed to heavy rain,
especially in tropical
areas!
OVERFISHING
Pollution
• Water Pollution
• Industrial and agricultural
chemicals
• PCBS + DDT
• Biological magnification
•
Residential sewage
•
Nonpoint sources
• Air Pollution
• Smog
• Acid Rain
• Greenhouse gases
• Particulates
INDUSTRIAL AND AGRICULTURAL
CHEMICALS
 One industrial pollutant is a
class of man made organic
chemicals called PCBs that
were widely used in many
industrial applications until the
1970s. After several large-scale
contamination events, PCBs
were banned.
 Other harmful industrial
pollutants are heavy metals like
cadmium, lead, mercury, and
zinc.
INDUSTRIAL AND AGRICULTURAL
CHEMICALS
 Large-scale monoculture has
increased the use of pesticides and
insecticides. These chemicals can
enter the water supply in the form of
runoff after heavy rains, or they can
seep directly into groundwater.
 DDT (used mainly in the 1950s)
effectivel y controls agricultural pests
and disease-causing mosquitoes . But,
when DDT gets into the water supply,
biological magnification can occur.
 Biological
magnification
occurs if a
pollutant, such as DDT, mercury, or a
PCB, is picked up by an organism and
is not broken down or eliminated from
its body. Instead, the pollutant
collects in body tissues.
SMOG AND PARTICULATES
 Smog is a gray-brown haze formed by chemical
reactions among pollutants released into the air by
industrial processes and automobile exhaust.
 Particulates are microscopic particles of ash and
dust released by certain industrial processes and
certain kinds of diesel engines.
Acid Rain
Affects:
Plant life
Aquatic environments
Statues
Ozone Depletion
The ozone absorbs harmful
UV rays from sunlight before it
reaches Earth’s surface.
Burning fossil fuels and forests
releases excess CO2, a
greenhouse gas.
Although some greenhouse
gases are necessary (temp
regulation), when excess
greenhouse gases accumulate in
the atmosphere, they contribute
to global warming and climate
change.
Biodiversity:
the diversity of life

Several types of biodiversity
Ecosystem diversity (types of habitats, environments)
 Species diversity
 Genetic diversity

Biodiversity has given us foods, medicines, and all kinds of
products. Who knows what else it could provide for us?
Types of biodiversity
1.
Diversity of genes
Chihuahuas, beagles, and rottweilers are all dogs—but
they're not the same because their genes are different.
Chihuahua
Beagle
Rottweilers
Types of biodiversity
Diversity of species
For example, monkeys, dragonflies, and
meadow beauties are all different species.
Saki Monkey
Golden Skimmer
Meadow Beauty
Types of Biodiversity
Variety of ecosystems
Prairies, Ponds, and tropical rain forests are all
ecosystems. Each one is different, with its own set of
species living in it.
Paines Prairie
Florida Sand hill Pond
Hoh Rain Forest
What do we get from
biodiversity?

Medicine


Agriculture


Herbal remedies, penicillin, etc.
Cross pollinating genetically advantaged
plants
Maintaining soil, clean water, and oxygen


Variety of habitats, such as wetlands, help
filter water
Forests help recycle nutrients
Should we be concerned about
biodiversity?
What we know:
The Earth is losing species at an alarming rate

3 species per hour are going extinct and 20,000
extinctions occur each year.

When species of plants and animals go extinct, many
other species are affected.

Human activity plays a major role in these
extinctions!
Threats to biodiversity

Habitat destruction






Number of species in area, including their
genetic diversity drops
Overhunting/fishing
Pollution (DDT, Acid rain)
Invasive species
Global Climate Change
Exploitation

Overharvesting makes plants unable to
regenerate fast enough.
Biodiversity Hot Spots

Ecological hot spots: Habitats with species in
immediate danger of extinction!

Ecological Footprint measures the extent to
which humanity is using nature's resources
faster than they can regenerate.
This world map shows each
country in proportion to its
ecological footprint.