1.
Man’s Impact on the
Environment

2.
Environment
• Physical
–Abiotic – (nonliving)
•Biological
–Biotic – (living)

3.
Ecosystems
• Dynamic interactions between plants,
animals,microorganisms, and their environment,
working together as a functional unit.
• Ecosystems will fail if they do not remain in
balance.
• No community can carry more organisms than
its food, water, and shelter can accommodate.
• Food and territory are often balanced by
natural phenomena – fire, disease, and
predators.
• Each organism has its own niche, or role, to
play.

4.
Ecology
• Scientific study of the relationship between organisms and their
environment
–Interactions between physical (abiotic) world and members of
same species
Ecosystems
• Collection of all the organisms that live in a particular place,
together with their nonliving, or physical, environment.
• Several levels of organization
• Connected directly or indirectly to other ecosystems.
Ecological Succession
• Change in the ecosystem over time due to organisms effecting it.
– short periods of time
– or several thousand years
• Succession often leads to a Climax Community.

5.
Kinds of Ecosystems
•Saltwater
•Freshwater
•Terrestrial
• Aquatic
• Ecosystem
– can be as large as the Sahara Desert, or as small as a puddle or
very small pool.
Biome
• A biome is a large area with similar flora, fauna, and
microorganisms.
– many similar ecosystems throughout the world
grouped together
Examples:
• Tropical rainforests
• Tundra in the arctic regions
• Evergreen trees in the coniferous forests

6.
Threats to Biodiversity
• Biodiversity has three components:
– Genetic diversity. This is the pool of genetic information and
variations found in the biosphere.
– Species diversity – The number of different life-forms found on the
planet. Almost 2 million species have been described to date.
– Ecosystem diversity – The unique assemblages of interact
communities scattered around the globe.
• When populations are reduced and/or species become extinct, genetic
information is lost forever without us ever knowing its potential benefit
to both that species, and to mankind.
• There is a list of threatened and endangered species worldwide. At
present 24% of mammalian species are endangered and
approximately 20% of freshwater fish have gone extinct or are
threatened with extinction. Many plants, insects, and other
invertebrates are also imperiled.
• Coral reef and tropical forest ecosystems have been and are being
seriously impacted by man’s activities.

7.
Importance of biodiversity
• Plants, microbes, and animals contain a vast genetic diversity that
may in the future provide many needed products for mankind.
• About 25% of all pharmaceuticals contain chemicals derived from
plants.
• Many companies are ‘bioprospecting’ for useful enzymes and
drugs.
• Healthy ecosystems controls runoff and erosion. They can absorb
excess nutrients before they cause europhication. They provide the
pollinators needed for agricultural crops, and provide organisms for
the biological control of agricultural pests.
• We don’t know what future discoveries can improve our lives, but
we do know that this won’t happen if we lose the biodiversity upon
which it depends.

8.
Chemical pollution in the environment
• Biological magnification is the reason that species at the top
of the food chain are more toxic than those at lower trophic
levels.
• Compounds, such as DDT and others, have in the past and are
presently causing environmental problems.
• Oil spills can destroy or disrupt local coastal ecosystems
and/or communities.
• Loss of large parts of the ozone layer have been attributed to
the use of chlorofluorocarbons (CFC) in aerosol cans. That is
way these compounds have been banned in air-conditioners
and refrigeration units.

9.
• Mercury is a naturally-occurring toxic trace element which
has a complex cycle between the Earth’s crust,
atmosphere and oceans. Some mercury is released by
natural processes but the predominant emissions to the
atmosphere result from human activities
• Mercury deposited in wetlands, lakes and streams can be
converted by natural bacteria into methyl mercury, a toxic
form that is accumulated and biomagnified at each link in
the food chain. In some circumstances, the result is sport
fish that would be toxic if eaten by humans and prey fish
that may be toxic to wildlife that eat them.

10.
Chemical Pollution• Eutrophication, caused by the
runoff of nitrates and other
nutrients from the land, has
created large areas that are
devoid of oxygen. There is a
major dead zone in the Gulf of
Mexico off the Mississippi
River Delta.
• Sea areas starved of oxygen
will soon damage fish stocks
even more than unsustainable
catches, the United Nations
believes.

11.
Global warming
• An average temperature rise of only a few degrees can lead to
significant sea level rise and altered rainfall pattern. The real
problem is that if we wait too long to control green house
gases, it may take a long time to see positive change.

12.
Critical habitat
• Critical habitat is the set of environmental conditions necessary to
maintain a species. It may be mature long-leaf pine forests for the
red-cockaded woodpecker, or old growth forests for the northern
spotted owl.
• It is necessary to determine the habitat needs of a species, before
a management plan can be developed. Since not every species
can be saved, it is also important to determine the keystone
species in order to best protect the overall community structure.

13.
Landscape ecology and movement corridors
• Landscape ecology- land
use patterns and make
biodiversity conservation a
priority.
• When habitats are
fragmented by human
development is sometimes
possible to develop
movement corridors to
connect pieces of high
quality habitat. These may
spans distances of many
miles or they may be local
man-made corridors to
protect wildlife.

14.
Protected Areas
• Not everything can be protected, so scientists are focusing
on protecting biodiversity hotspots. These are small
areas that have a relatively high number of species.
Hotspots can be seen in purple on the map below.
Because of their great diversity, these hotspots are also at
great risk from development.

15.
Restoration Ecology
• Restoration ecology is
to develop ways to return
degraded ecosystems to
conditions as similar as
possible to their natural,
predegraded state.
• Bioremediation uses
plants and microbes to
remove toxic chemicals
for polluted areas. This
has been used
successfully to help
clean-up oil spills.

16.
Sustainable development
• Using and protecting resources in such a manner that they are
available to the generations that come after us.
• Sustainable development will depend not only on continued
research and application of ecological knowledge. It will also
require us to connect the life sciences with the social sciences,
economics, and humanities.
• Conservation and restoration of diversity is only one side of
sustainable development; the other key facet is improving the
human condition. Public commitment and cooperation of nations
are essential to the success of this endeavor.
• Each of us must play our part, no matter how small, if this is to
become a reality.