Human Impact on Biodiversity

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Human Impact on Biodiversity
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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.

• the assortment, or variety, of living things in
  an ecosystem.
• 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

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Biodiversity

• Why does biodiversity matter?

• Biodiversity is one of the Earths greatest
  resources. Species of many kinds have provided us
  with food, industrial products, and medicines.
• Ex painkillers, antibiotics, heart drugs,
  antidepressants and anticancer drugs.

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• How do humans reduce biodiversity?

• Human activity can reduce biodiversity by
• Altering habitats
• Hunting species to extinction
• Introducing toxins into food webs
• Introducing foreign species to new environments.

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Threats to Biodiversity- Altering Habitats

• When land is developed natural habitats may be
  destroyed. This causes the species in the area
  to
• Development may also divide the ecosystems into
  separate biological islands. This is called

• Relocate or vanish
• Habitat Fragmentation

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Threats to Biodiversity- Altering Habitats

• Very few species can live in small areas.
• Species will have smaller populations
• Be vulnerable to further disturbance, climate
  change and loss.

• How are species living on these biological
  islands affected?

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Biodiversity
Central Park, NYC

• An example of a biological island would be
  Central Park in New York city.

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Threats to Biodiversity- Over Hunting

• Over Hunting for food and other products like
  horns or body parts has pushed some species to
  extinction.

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
California red-legged frog, now a federally
protected endangered species, was over hunted for
food
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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.

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Some of the Most Endangered Animals 1
Ivory-Billed Woodpecker - A North American bird
so endangered it may actually be extinct 2 Amur
Leopard - The worlds rarest cat Only 40 left in
Russias Far East 3 Javan Rhinoceros - No more
than 60 of these swamp-dwelling Asian rhinos
exist 4 Greater Bamboo Lemur - Heres the
scarcest of Madagascars fast-dwindling lemur
species 5 Northern Right Whale - Hunted to near
extinction, 350 right whales still swim the
Atlantic
6 Mountain Gorilla - Their habitat is shrinking,
and fewer than 700 remain 7 Leatherback Sea
Turtle - The population of the worlds largest
turtle is dropping at an alarming rate 8 Siberian
(or Amur) Tiger - The worlds biggest cat weighs
as much as 300 kilos (660 pounds) 9 Chinese Giant
Salamander - Humans are eating the worlds
largest amphibian into extinction 10 Hawaiian
Monk Seal - Scientists dont know why this seals
population keeps declining
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Threats to Biodiversity-Pollution

• One of the most serious problems with pollution
  is biological magnification.

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Threats to Biodiversity-Pollution

• What is 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.

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Threats to Biodiversity-Pollution

• An example of Biological magnification is in the
  1960s 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.

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Threats to Biodiversity-Introduced Species

• An introduced species that reproduces rapidly has
  no natural predators or parasites.

• Sometimes a plant or animal may be introduced
  into a new environment either accidentally or
  intentionally.
• An invasive species is..

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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
• In recent years, the Asian longhorned beetle
  (Anoplophora glabripennis) and other wood-boring
  beetles have been entering North America in solid
  wood packing material from Asia. Some of these
  insects have the potential to become very serious
  pests of North American forests.
• 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.

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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.
  Teasels unusualand by some perspectives,
  attractive flower heads have led to its use as a
  horticultural plant, in flower arrangements and
  in the craft trade.