Transcript Human Activities Affect The Environment

Human Activities Affect The
Environment
• Humans Use Many Resources
– Humans rely on the environment, and use renewable and
nonrenewable resources
• Pollution Endangers Biodiversity
– Pollution= addition of harmful substances (chemicals,
bacteria, dirt) to the environment (soil, air, water)
– Biodiversity= number & variety of life forms within an
ecosystem. (pollution decreases this)
• Habitat Loss Endangers Biodiversity
– If living space is limited or a food source is removed (due
to pollution) then the number of species in a biological
community will be reduced.
Humans use many Resources
• RENEWABLE RESOURCE: resource that can
be used over & over again (trees, sunlight energy,
water). Can be replaced naturally or by humans
in a short amount of time, but if overused or
poorly managed, may run out (except for
sunlight).
• NONRENEWABLE RESOURCES: resources
that cannot be replaced. May be replenished by
natural processes, but not quickly enough for
human purposes. Are often underground, but
technology is making it easier to find & use up
these resources. Coal, petroleum, & natural gas
(all fossil fuels) are nonrenewable resources used
for heating, industry, & transportation. Minerals
like gold & copper are also nonrenewable.
•
Pollution:
Air
Quality
Air quality affects entire ecosystems; (1980 Mt. St. Helen
eruption in West Coast, 3 days later ash landed in East
Coast).
• Fossil fuels release sulfur dioxide, nitrogen dioxide, & carbon
monoxide into air, leading to acid rain.
• Acid rain occurs when the above mix with water in air to
form acid droplets of rain, snow, or mist. This has killed all
the fish in some of New York’s lakes, and damages tree
leaves and soil. This leads to habitat destruction and lower
food source & less biodiversity.
•
Pollution:
Water
Quality
Chemicals or waste that drain off of farm fields, animal
feedlots, & landfills, and oil spills, soil erosion & discharge
of waste water all cause water pollution. (40 years ago this
lead to Lake Erie having everything in it “die”)
• This affects entire ecosystem; when fish & amphibians are
exposed, entire food web is affected. If fish die off, birds may
not have food, and either die or move to a new habitat.
Biodiversity is then decreased. (Duwamish River in
Washington has over 600 million gallons of untreated waste
& storm water drain into it (bacteria & chemicals kill fish)
Pollution Across Systems
• Pollution can spread among ecosystems by abiotic
factors (wind with Mt. St. Helen ash, or acid rain).
• Pollution can also move between air and water
(chemical pollutants run off land into body of water,
& may evaporate with water into air, moving into
the atmosphere.
Habitat Loss
• By humans removing natural resources, populations
relying on those are less likely to survive.
Removing large areas of land (due to land
development) that is habitat to many species, takes
away food, space, shelter & protection for them.
• Sometimes humans move species into new habitats
(on purpose or accidentally). This may drastically
change the habitat. Over time, these Invasive
Species may replace the native species by out
competing them.
– Purple loosestrife was brought to U.S. from Europe in
1800’s (as a garden plant & medicinal herb). 1 plant
makes 2million seeds/yr. Carried by wind/water/animals
/humans, the seeds sprout in wetlands to replace native
plants that animals feed on. This causes animals to
disappear with the native plants.
By protecting biodiversity, we can help ecosystems
thrive & recover. This directly benefits humans
(many medicines are based on natural compounds
from plants that only grow in certain ecosystems).