Transcript chapter 5 - Avon Community School Corporation

CHAPTER 5
BIODIVERSITY AND CONSERVATION
• BIODIVERSITY
• MAIN IDEA: Biodiversity maintains a healthy biosphere and
provides direct and indirect value to humans.
• WHAT IS BIODIVERSITY?
• Biodiversity is the variety of life in an area that is
determined by the number of different species in that area.
– Biodiversity increases the stability of an ecosystem and
contributes to the health of the biosphere.
• There are 3 types of biodiversity:
– Genetic diversity
– Species diversity
– Ecosystem diversity
• Extinction is when the last member of the species dies.
• GENETIC DIVERSITY
• Genetic diversity is the variety of genes
or inheritable characteristics that are
present in a population.
• Genetic diversity within interbreeding
populations increases the chances that
some individuals will survive during
changing environmental conditions or
during an outbreak of disease.
• QUESTION: In the picture below, what are some of
the different heritable characteristics that you see
and how could some of those differences be
helpful?
• SPECIES DIVERSITY:
• Species diversity is the number of
different species and the relative
abundance of each species in the a
biological community.
• Species diversity is not evenly distributed
over the biosphere.
–Species diversity increases as you move
further away from the poles & closer to
the equator.
• QUESTION: In the picture below how many
different species are present?
• ECOSYSTEM DIVERSITY
• Ecosystem diversity is the variety
of ecosystems that are present in
the biosphere.
–Ecosystems are made up of
interacting populations and the
abiotic factors that support
them.
• THE IMPORTANCE OF BIODIVERSITY
• DIRECT ECONOMIC VALUE
• Direct economic value for maintaining biodiversity include:
– Food
• Need diverse genetic pools to help keep the food source safe
from the effects of devastating diseases or insects.
– Done through genetic engineering when scientists transfer
genes from one organism to another
– Clothing
– Energy
– Medicine
• Mostly produced from plants or other organisms.
– EX: Madagascar periwinkle flower yields an extract to treat
some forms of leukemia increasing survival rate from 20%
to more than 95%.
– Shelter
• INDIRECT ECONOMIC VALUE
• Healthy biosphere provides many services to
humans and other organisms.
– Plants provide oxygen & remove carbon dioxide
– Safe water for drinking
– Cycling nutrients
– Provide protection against floods and droughts
– Preserve fertile soils
– Detoxify and decompose wastes and regulate
local climates
• SECTION 2 – THREATS TO BIODIVERSITY
• MAIN IDEA: Some human activities reduce
biodiversity in ecosystems, and current
evidence suggests that reduced biodiversity
might have serious long term effects on the
biosphere.
• QUESTION: What happens when a new
building project starts in an area that was
previously undeveloped?
• EXTINCTION RATES
• Background extinction is the gradual process of species becoming
extinct.
– Occurs when stable ecosystems are changed by: other
organisms, climate changes, or natural disasters
– Predicted that 1/3 to 2/3 of all plant & animal species, mostly
near the equator, will become extinct during 2nd half of this
century.
• Mass extinction is events where a large percentage of all living
species become extinct in a relatively short period of time.
– Last one was 65 million years ago for dinosaurs
– Large percentage of extinctions take place on islands
• Small populations
– Affected by newly introduced predators, can’t escape
island, nonnative species, and disease
• FACTORS THAT THREATEN
BIODIVERSITY
• Natural resources are all materials
and organisms found in the
biosphere, including minerals, fossil
fuels, nuclear fuels, plants, animals,
soil, clean water, clear air, and solar
energy.
• OVEREXPLOITATION
• Overexploitation is the over use of
species that have economic value,
which increases their current rate of
extinction
–EX: N. American bison
• Previously overexploitation was the
primary cause of species extinction,
NOW it is the destruction of habitat.
• HABITAT LOSS
• Habitat loss is the result of:
– Destruction of habitat
• Tropical rain forest contains more than half of all
species on Earth
• Clearing the tropical rain forest for agricultural crops
or grazing land reduces habitat & species
– Disruption of habitat
• Fig. 11, Pg. 125 shows how the # of harbor seals & sea
lions declined, setting off the chain reaction of what
the whales ate (now more sea otters), which normally
ate the sea urchins, now their population is up & the
kelp is way down.
• FRAGMENTATION OF HABITAT
• Habitat fragmentation is the separation of an ecosystem into
small pieces of land
– Populations will stay in the small parcels because they are
either unable or unwilling to cross the human-made barriers.
• Problems:
– Smaller the land means fewer species that are supported
– Reduces opportunities for individuals in one area to
reproduce with individuals from another area
• Genetic diversity decreases over time causing populations
to become less resistant to disease, or able to respond to
changing environmental conditions.
• Creates edge effects, which is when boundaries of the
ecosystem have different abiotic factors like temperature,
wind & humidity than the rest of ecosystem.
• POLLUTION
• Pollution changes the composition of air, soil and water.
– Pesticides
• DDT – enters food chain & remains in tissues of
organisms
– Industrial chemical
• PCB – enters food chain & remains in tissues of
organisms
• Biological magnification is the increasing concentration of
toxic substances in organisms as trophic levels increase in a
food chain or web.
– Higher level carnivores are most affected
• EX: Bald eagle – caused the thinning of the egg shells
so no new eagles were being born
• POLLUTION – CONTINUED
• Acid precipitation is created when fossil fuels are burned
releasing sulfur dioxide and nitrogen oxides into the
atmosphere.
• Reaction with water & other substances in the air create
sulfuric acid & nitric acid
– Will remove calcium, potassium and other nutrients
from soil
– Will damage plant tissues & slows their growth or kills
• Eutrophication occurs when fertilizers, animal waste,
sewage, or other substances rich in nitrogen and
phosphorus flow into water, crease extensive algae growth
– Algae will use up the oxygen supply causing other
organisms to suffocate
• INTRODUCED SPECIES
• Introduced species are nonnative species that are
either intentionally or unintentionally transported
to a new habitat.
– Reproduce rapidly because there are no
predators, parasites and competition to keep
them controlled in the new environment.
• Now considered an invasive species
–EX: Fire ants
– Invasive species believe to be responsible for 40%
of the extinctions since 1750
• SECTION 3 – CONSERVING BIODIVERSITY
• MAIN IDEA – People are using many approaches
to slow the rate of extinctions and to preserve
biodiversity.
• NATURAL RESOURCES
• Natural resources are used to meet our basic
needs
– Industrialized countries use more natural
resources per person than developing countries
• 2 types of natural resources:
– Renewable
– Nonrenewable
• RENEWABLE RESOURCES
• Renewable resources are any resources that is
replaced by natural processes faster than they are
consumed
– EX: solar energy, agriculture, plants, animals, clean
water and air
• These resources are NOT unlimited.
• Any resource can be depleted. If depleted, natural
resource would change from renewable to
nonrenewable.
– EX: Removing a few trees = renewable resource
Removing a whole forest = nonrenewable
resource
• NONRENEWABLE RESOURCE
• Nonrenewable resources are found on Earth in limited amounts
or that are replaced by natural processes over extremely long
period of time.
– EX: fossil fuels and minerals deposits
– Species are considered nonrenewable when extinction
occurs because now it is lost forever
• SUSTAINABLE USE
• Sustainable use happens when we use the resources at a rate
where they can be replaced or recycled them while preserving
the long-term environmental health of the biosphere.
• Conservation of resources happens when we reduce the
amount of resources that are consumed, recycled resources
(aluminum cans) occurs, and we preserve and use ecosystems in
a responsible manner.
• PROTECTING BIODIVERSITY
• US helps protect biodiversity by establishing national parks &
nature reserves
– EX: 1st national park – Yellowstone in 1872
• Currently 7% of the world’s land is set aside as a natural reserve,
some of them megareserves
• To be classified as a biodiversity hot spot the region must have
lost at least 70% of the original habitat and there must be at
least 1500 species of plants that are endemic (species found
only in specific geographic areas with critical levels of habitat
loss)
– Hot spots shown on pg. 132
• To improve the survival of biodiversity conservationists are
developing corridors or passageways to connect small parcels of
land allowing the organisms to move from one area to another
safely.
• RESTORING ECOSYSTEMS
• Biodiversity is destroyed in an area when it no
longer provides the abiotic and biotic factors
needed for a healthy ecosystem.
–EX: clearing tropical rain forest for farming
& then is unproductive after a few years.
• Recovery from human or natural disasters can
happen, but depends on size of the area
affected and the type of disturbance.
–Larger the area = longer time