3.3 Human Impacts on Biodiversity Flashcards
Humans affect biodiversity by:
Destroying habitats
Creating Pollution
Invasive Species
Overexploitation
Climate Change
earth today
-Mass extinction is currently taking place
-Exact scale is uncertain as we only know a fraction
of the total number of species on Earth.
-approx. 12% of known bird species are
endangered
-of approx. 20,000 known plant species in North
America, at least 300 are at risk (e.g. 86% of
mosses face extinction)
-approx. 37% of known fish have become extinct
during historical time or are at risk
habitat loss
Water Fronts
-highly populated
-more land is needed for agriculture, roads and
communities
-fertilizer runoff can flow into water, creating dead
zones via eutrophication (areas with low levels of
O2)
-with proper care shorelines can recover
-(e.g. The Great Lakes Water Quality Agreement
b/w CAN and USA has reduced fertilizer runoff)
Habitat loss is the ___________ to biodiversity of life.
greatest threat
As human pop grows, we develop land for;
Communities
Farms
Obtaining natural resources (e.g. coal and lumber)
If species cannot adapt or move, they will _______
not survive
Habitat Fragmentation
altering small areas within a large region, creating patchwork of altered and original habitats
Regions within Ontario have made a commitment to practice __________ by replanting cut trees with _________
sustainable forestry; seedlings
Organizations like Forest Stewardship Council work to …
conserve and protect forest habitats
Invasive Species
Non-native species that invade new habitats
-prey on native species and outcompete them for
resources
-humans have introduced these invasive species
intentionally or accidentally as people travel
-e.g. Japanese plant kudzu, Emerald ash borer,
Zebra mussels, Asian carp
Pollution
Cars and coal burning plants release GHG that can contribute to global warming and acid rain
-as temp. rises, species must adapt, move, or die
-acid rain damages forests, fresh water, and soil by
altering the pH
Pesticide use has inadvertently killed many organisms besides those targeted
-e.g. In South America pesticides were sprayed to
control grasshoppers yet also killed 6000 hawks.
-toxicity can bioaccumulate thru food chains (e.g.
atrazine changing the sex of frogs)
Toxicity can _________ thru food chains (e.g. atrazine changing the sex of frogs)
bioaccumulate
different types of pollution
Light pollution
Chemical pollution
Sewage pollution
Plastic pollution
Air emissions (type of air pollution- NOx, SOx)
Overexploitation
Harvesting resources faster than they can be replaced
-e.g. Rosi periwinkle in Madagascar nearly picked
to extinction – used as a cancer trmt drug
-e.g. collapse of cod fisheries from 479,141 to
12,490 tons in only 7 years…still hasn’t recovered
Climate Change
Human activities have increased the level of CO2 in the atmosphere;
-deforestation
-burning fossil fuels
-burning peat forests
-raising livestock
-draining wetland ecosystems
examples of disease outbreaks that climate change has caused
e.g. Malaria, H1N1, SARS increase
how does climate change result in plant migration
Grasslands will replace Boreal Forests
how does climate change result in animal migration
Animals will have to migrate more North
how does climate change result in extreme weather
Increase in energy in our weather systems
how does climate change result in extreme weather in increase of CO2
Changes pH levels in water; changes animal behaviour
how does climate change result in extreme weather in water availibility/quality
Reduced in many arid (dry) and semi-arid regions
Aral Sea
Synergistic Effect
The impact of several human activities combined
The Convention on Biological Diversity is an international treaty signed by 161 countries that helps …
sustain life on Earth
Ex-situ conservation
-Removing species from their habitats to protect
them (e.g. zoos)
-Used when habitat is no longer there, or existing
pop. is small
-Considered a last resort
