Download Biodiversity Notes

Human Impact on
Biodiversity
Biodiversity
• One reason why humans need to change our
way of thinking about the earth and its
resources is the loss of biodiversity.
• Biodiversity is = assortment, or variety, of
living things in an ecosystem
Biodiversity
• Biodiversity needs to be maintained
because it is key to the discovery of
potential medicines and new species
▫ Ex. Alaska has more biodiversity than Missouri
• Biodiversity is one of the Earth’s greatest
resources. Species of many kinds have provided
us with food, industrial products, and medicines.
▫ Ex: painkillers, antibiotics, heart drugs,
antidepressants and anticancer drugs.
•
Human activity can reduce biodiversity
by:
1. Altering habitats
2. Hunting species to
extinction
3. Introducing toxins into
food webs
4. Introducing foreign
species to new
environments.
Although not due to humans, climate
change can also reduce biodiversity.
Threats to BiodiversityAltering Habitats
• When land is developed natural
habitats may be destroyed. This
causes the species in the area to:
• Relocate or vanish
• Development may also divide the
ecosystems into separate
“biological islands”. This is
called…
• Habitat Fragmentation
Threats to Biodiversity- Altering
Habitats
• Biological Islands:
▫ Very few species can live in small areas.
▫ Species will have smaller populations
▫ Be vulnerable to further disturbance,
climate change and loss.
Biodiversity
• An example of a biological
island would be Central Park in
New York city.
Central Park, NYC
Threats to BiodiversityOver Hunting
• Over Hunting for food and other products
like horns or body parts has pushed some
species to extinction.
California red-legged frog,
now a federally protected
endangered species, was
over hunted for food
Some medicinal
plants, such as
American
ginseng, have
also been so
enthusiastically
collected that it is
now very hard to
find them in the
wild
Threats to Biodiversity- Over Hunting
• What has been done to
protect species from
extinction?
• An endangered species list has
been generated and laws have been
enacted to protect species.
• Delegates from many countries
meet to make these laws at the
Convention on International Trade
in Endangered Species (CITES).
▫ However, it is difficult to enforce these
laws in remote areas.
Some of the Most Endangered
Animals
Ivory-Billed Woodpecker - A North
American bird so endangered it
may actually be extinct
Amur Leopard - The world’s rarest
cat: Only 40 left in Russia’s Far
East
Javan Rhinoceros - No more than
35 of these swamp-dwelling Asian
rhinos exist
Northern Sportive Lemur - Here’s
the scarcest of Madagascar’s fastdwindling lemur species
Northern Right Whale - Hunted to
near extinction, 350 right whales
still swim the Atlantic
Sumatran Orangutan
Giant Panda
The Saolo – an Asian Unicorn
So rare it is almost mythological,
the saolo hangs on by its hoof tips
in a forest full of poachers’ snares
Leatherback Sea Turtle - The
population of the world’s largest
turtle is dropping at an alarming
rate
Siberian (or Amur) Tiger - The
world’s biggest cat weighs as much
as 300 kilos (660 pounds)
Chinese Giant Salamander Humans are eating the world’s
largest amphibian into extinction
The Little Dodo Bird
Samoa’s little Dodd bird is an
innanent danger of following the
larger one
Hawaiian Monk Seal
Western Lowland Gorilla
Threats to Biodiversity-Pollution
• One of the most
serious problems
with pollution is
biological
magnification.
Threats to Biodiversity-Pollution
• Biological Magnification: accumulation of
toxins in the food chain.
▫ Pollutants can move up the food chain.
▫ predators eat contaminated prey
▫ pollution accumulates at each stage of the food
chain
▫ Top consumers, including humans, are most
affected
• Toxins do not break down by natural
processes or get eliminated from the
body in this process.
Threats to Biodiversity-Pollution
• An example of Biological magnification is in the 1960’s a
pesticide named DDT was spread.
• What did DDT do to organisms?
• DDT caused fish eating animals
like the Osprey, Brown Pelican
and the Bald Eagle to have very
fragile eggs. Most of the eggs
did not survive. Eventually
these birds were put on the
endangered species list.
Threats to Biodiversity-Introduced
Species
• Sometimes a plant or animal may be introduced into a new
environment either accidentally or intentionally.
• Invasive Species: An introduced species that reproduces
rapidly has no natural predators or parasites.
Australia's Invasive Problem…
• Cane Toad – brought in 1935 to control the cane
beetle but are prolific breeders and bufotoxin
kills native animals
• Red Fox – brought in 1855 for recreational
hunting
Threats to Biodiversity-Introduced
Species
• Species to look out for in Missouri
• Zebra Mussels
▫ Zebra mussels and a related species, quagga mussels, are fingernail-sized
black-and-white striped bivalve mollusks native to the Caspian Sea region
of Asia. They came to North American waters in international shipping
ballast water and were discovered in Lake St. Clair near Detroit in 1988.
• Asian Longhorned Beetle
▫ An unwanted arrival from Asia that's now living in parts of the United
States, the Asian longhorned beetle could destroy millions of acres of
American hardwoods. Report any sightings
Gypsy Moths
▫ The gypsy moth was introduced to the East Coast in 1869 and since then
has been spreading slowly westward. When it arrives, the gypsy moth will
be especially devastating to Missouri forests because one of its favorite
foods is oak leaves.
▫ Link to all of Missouri’s Invasive species - http://mdc.mo.gov/discovernature/field-guide/invasive-species/invasive-species-field-guide
Threats to Biodiversity-Introduced
Species
• Species to look out for in Missouri
• Rusty Crayfish
▫ The rusty crayfish is native to parts of Ohio, Kentucky, Indiana and
Michigan but has spread to other states or areas where it can cause
problems for other animals and plants. Rusty crayfish were probably
spread by anglers who transported them for use as fishing bait.
• Common and Cut-leaved Teasel
▫ Like many of our problem weeds, teasel is an exotic plant that is native to
Europe. It was introduced to North America, possibly as early as the
1700s, because the prickly stem was used in the textile industry to raise
the nap of cloth. Teasel’s unusual—and by some perspectives, attractive—
flower heads have led to its use as a horticultural plant, in flower
arrangements and in the craft trade.
Asian Carp
• https://www.youtube.com/watch?v=rPeg1tbBt0
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• https://www.youtube.com/watch?v=qfG4vsJ5_
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