X-rays from a Central “Exhaust Vent” of the Galactic Center Chimney
Extinction causes and consequences .pptx
1. Core Case Study: Polar Bears and
Global Warming
Polar Bears
• 20,000-25,000 in the Arctic
• Most calories in winter from seals on sea ice
• Environmental impact on polar bears
• Less summer sea ice from global warming
• Could be gone from wild by 2100
• 2008: Threatened species list
3. What Role Do Humans Play in the Extinction of
Species?
Species are becoming extinct 100 to 1,000 times faster
than they were before modern humans arrived on the
earth (the background rate), and by the end of this
century, the extinction rate is expected to be 10,000
times the background rate.
4. Extinctions Are Natural but Sometimes
They Increase Sharply
• Biological extinction
• No species member alive
• Background extinction
• Natural low rate of extinction
• Extinction rate
• Percentage or number of species that go extinct in a certain time period
5. Extinctions Are Natural but Sometimes
They Increase Sharply (2)
• Mass extinction
• 3-5 events
• 50-95% of species became extinct
• From global changes in environmental conditions: major climate change,
volcanoes, asteroid impacts
• Levels of species extinction
• Local extinction
• Ecological extinction
• Biological extinction
6. Some Human Activities Are Causing Extinctions
Human involvement
• Human activity has disturbed at least half of the earth’s land surface
• Converts grasslands and forests to crop fields and urban areas
• Pollution of land and water
7. Extinction Rates Are Rising Rapidly
Extinction Rates
• Current extinction rate is at least 100 times higher than typical
background rate of .0001%
• Will rise to 10,000 times the background rate by the end of the century
• Rate will rise to 1% per year
• ¼ to ½ of the world’s plant and animal species
8. • Growth of human population will increase this loss
• Rates are higher where there are more endangered species
• Tropical forests and coral reefs, wetlands and estuaries—sites of new
species—being destroyed
• Speciation crisis
Extinction Rates Are Rising Rapidly
9. Endangered and Threatened Species
Are Ecological Smoke Alarms
• Endangered species
• So few members that the species could soon become extinct
• Threatened species (vulnerable species)
• Still enough members to survive, but numbers declining -- may soon be
endangered
10. Stepped Art
Fixed
migratory
patterns
Blue whale,
whooping crane,
sea turtle
Feeds at high
trophic level
Bengal tiger, bald
eagle, grizzly bear
Narrow
distribution
Elephant seal,
desert pupfish
Commercially
valuable
Snow leopard, tiger,
elephant, rhinoceros,
rare plants and birds
Low reproductive
rate
Blue whale, giant
panda, rhinoceros
Characteristic Examples
Rare African violet,
some orchids
Large territories
California condor,
grizzly bear, Florida
panther
Specialized
niche
Blue whale, giant
panda, Everglades
kite
Fig. 9-3, p. 194
12. Estimating Extinction Rates
• Three problems with estimating extinction rate
1. Hard to document due to length of time
2. Only 1.9 million species identified
3. Little known about nature and ecological roles of species identified
• Approaches
1. Study extinction rates over last 10,000 years and then compare with the fossil record
2. Use species–area relationship
3. Mathematical models
13. The Passenger Pigeon: Gone Forever
Passenger Pigeon
• Once one of the world’s most abundant birds
• Fly in flock
• Passenger pigeon hunted to extinction by 1900
• Habitat loss
• Commercial hunting
• Easy to kill: flew in large flocks and nested in dense colonies
15. Why Should We Care about the
Rising Rate of Species Extinction?
We should prevent the premature extinction of wild species because of the
economic and ecological services they provide and because they have a
right to exist regardless of their usefulness to us.
16. Species Are a Vital Part of the Earth’s Natural
Capital
• 4 reasons to prevent extinctions
1. Species provide natural resources and natural services
• Insects for pollination
• Birds for pest control
2. Most species contribute economic services
• Plants for food, fuel, lumber, medicine
• Ecotourism
17. Species Are a Vital Part of the Earth’s Natural
Capital
3. It will take 5-10 million years to regain species biodiversity
4. Many people believe species have an intrinsic right to exist
18. Fig. 9-6, p. 195
Natural Capital Degradation: Endangered Orangutans in a
Tropical Forest
19. Fig. 9-7, p. 196
Pacific yew Taxus
brevifolia, Pacific
Northwest
Ovarian cancer
Rosy periwinkle
Cathranthus
roseus,
Madagascar
Hodgkin's
disease,
lymphocytic
leukemia
Rauvolfia
Rauvolfia sepentina,
Southeast Asia
Anxiety, high blood
pressure
Neem tree
Azadirachta
indica, India
Treatment of
many diseases,
insecticide,
spermicides
Foxglove
Digitalis purpurea,
Europe Digitalis for
heart failure
Cinchona
Cinchona
ledogeriana, South
America Quinine for
malaria treatment
20. Fig. 9-8, p. 197
Endangered Hyacinth Macaw is a Source
of Beauty and Pleasure
21. How do Humans Accelerate
Species Extinction?
The greatest threats to any species are (in order) loss or degradation of its
habitat, harmful invasive species, human population growth, pollution,
climate change, and overexploitation.
22. Loss of Habitat Is the Single Greatest
Threat to Species: Remember HIPPCO
Threats to biodiversity
• Habitat destruction, degradation, and fragmentation
• Invasive (nonnative) species
• Population and resource use growth
• Pollution
• Climate change
• Overexploitation
23. Habitat Fragmentation
• Habitat fragmentation
• Large intact habitat divided by roads, crops, urban development
• Leaves habitat islands
• Blocks migration routes
• Divides populations
• Inhibits migrations and colonization
• Inhibits finding food
• National parks and nature reserves as habitat islands
24. Fig. 9-9, p. 198
Natural Capital Degradation
Causes of Depletion and Extinction of Wild Species
Underlying Causes
• Population growth
• Rising resource use
• Undervaluing
natural capital
• Poverty
Direct Causes
• Habitat loss • Pollution • Commercial hunting
and poaching
• Habitat degradation
and fragmentation
• Climate change
• Sale of exotic pets and
decorative plants
• Introduction of
nonnative species
• Overfishing
• Predator and pest control
25. Fig. 9-10a, p. 199
Indian Tiger
Range 100 years ago
Range today
26. Fig. 9-10b, p. 199
Black Rhino
Range in 1700
Range today
27. Fig. 9-10c, p. 199
African Elephant
Probable range 1600
Range today
28. Fig. 9-10d, p. 199
Asian or Indian Elephant
Former range
Range today
29. Stepped Art
Indian
Tiger
Range 100 years ago
Range today
Black
Rhino
Range in 1700
Range today
African
Elephant
Probable range 1600
Range today
Asian or Indian
Elephant
Former range
Range today
Fig. 9-10, p. 199
30. Some Deliberately Introduced Species Can Disrupt
Ecosystems
• Most species introductions are beneficial
• Food
• Shelter
• Medicine
• Aesthetic enjoyment
• Nonnative species may have no natural
• Predators
• Competitors
• Parasites
• Pathogens
31. Fig. 9-11a, p. 200
Deliberately Introduced Species
Purple loosestrife European starling African honeybee
(“Killer bee”)
Nutria Salt cedar
(Tamarisk)
Marine toad (Giant
toad)
Water hyacinth Japanese beetle Hydrilla European wild
boar (Feral pig)
32. Fig. 9-11b, p. 200
Accidentally Introduced Species
Sea lamprey
(attached to lake
trout)
Argentina fire ant Brown tree snake Eurasian ruffe Common pigeon
(Rock dove)
Formosan termite Zebra mussel Asian long-horned
beetle
Asian tiger
mosquito
Gypsy moth
larvae
33. Stepped Art
Deliberately introduced species
Purple
loosestrife
European
starling
African honeybee
(“Killer bee”)
Nutria Salt cedar
(Tamarisk)
Marine toad
(Giant toad)
Water
hyacinth
Japanese
beetle
Hydrilla European wild
boar (Feral pig)
Accidentally introduced species
Sea lamprey
(attached to
lake trout)
Argentina
fire ant
Brown tree
snake
Eurasian
ruffe
Common pigeon
(Rock dove)
Formosan
termite
Zebra
mussel
Asian long-
horned beetle
Asian tiger
mosquito
Gypsy moth
larvae Fig. 9-11, p. 200
34. The Kudzu Vine
Kudzu: Invasive Species:
• Imported from Japan in the 1930s
• “ The vine that ate the South”
• Could there be benefits of kudzu?
• Fiber for making paper
• Kudzu powder reduces desire for alcohol
35. Fig. 9-12, p. 201
Kudzu Taking Over an Abandoned
House in Mississippi, U.S.
36. Some Accidentally Introduced Species
Can Also Disrupt Ecosystems
• Argentina fire ant: 1930s
• Reduced populations of native ants
• Painful stings can kill
• Pesticide spraying in 1950s and 1960s worsened conditions
• 2009: tiny parasitic flies may help control fire ants
• Burmese python
• Florida Everglades
37. Fig. 9-13, p. 202
Fight Between a Python and Alligator
38. Other Causes of Species Extinction
Other cases
• Human population growth
• Overconsumption
• Pollution
• Climate change
• Pesticides
• Bioaccumulation
• Biomagnification
39. How Can We Protect Wild Species from
Premature Extinction?
We can reduce the rising rate of species extinction and help to protect
overall biodiversity by establishing and enforcing national environmental
laws and international treaties, creating a variety of protected wildlife
sanctuaries, and taking precautionary measures to prevent such harm.
40. International Treaties and National Laws
Help to Protect Species
Treaties and Laws:
• 1975: Convention on International Trade in Endangered Species (CITES)
• Signed by 172 countries
• Convention on Biological Diversity (BCD)
• Focuses on ecosystems
• Ratified by 190 countries (not the U.S.)
41. We Can Establish Wildlife Refuges
and Other Protected Areas
• Wildlife refuges
• Most are wetland sanctuaries
• More needed for endangered plants
• Could abandoned military lands be used for wildlife habitats?
42. Fig. 9-21a, p. 211
Pelican Island National Wildlife Refuge
43. Gene Banks, Botanical Gardens, and
Wildlife Farms Can Help Protect Species
Other Solutions
• Gene or seed banks
• Preserve genetic material of endangered plants
• Botanical gardens
• Living plants
• Farms to raise organisms for commercial sale
44. Zoos and Aquariums Can Protect
Some Species
• Techniques for preserving endangered terrestrial species
• Egg pulling
• Captive breeding
• Artificial insemination
• Embryo transfer
• Use of incubators
• Cross-fostering
• Goal of ultimately releasing/reintroducing populations to the wild
45. Fig. 9-22, p. 213
What Can You Do? Protecting Species
Editor's Notes
Figure 9.1: On floating ice in Svalbard, Norway, a polar bear feeds on its seal prey. Polar bears in the Arctic could become extinct sometime during this century if projected atmospheric warming melts much of the floating sea ice on which they hunt seals. Question: What do you think about the possibility that the polar bear might become extinct mostly because of human activities? Explain.
Figure 9.4: Endangered natural capital.
This graph shows the estimated percentages of various types of known species that are threatened with extinction because of human activities (Concept 9-1). Question: Why do you think plants (see Photo 4 in the Detailed Contents) and fish species top this list? (Data from International Union for Conservation of Nature, Conservation 2009)
Figure 9.5: Because of human activities, the North American passenger pigeon became extinct in the wild in 1900. In 1914, the world’s last known passenger pigeon died in a zoo in the U.S. city of Cincinnati, Ohio.
Figure 9.6: Natural capital degradation.
These endangered orangutans are shown in their rapidly disappearing tropical forest habitat. In 1900, there were over 315,000 wild orangutans, which are found only in the tropical forests of Indonesia and Malaysia. According to the WWF, today there are fewer than 56,000 left in the wild (90% of them in Indonesia). These highly intelligent animals are disappearing at a rate of more than 1,000–2,000 per year because of illegal smuggling and the clearing of their tropical forest habitat to make way for plantations that supply palm oil used in cosmetics, cooking, and the production of biodiesel fuel. An illegally smuggled, live orangutan sells for a street price of up to $10,000. Without urgent protective action, the endangered orangutan may be the first great ape species to become extinct, primarily because of human activities. Question: What difference will it make if human activities cause the extinction of the orangutan?
Figure 9.7: Natural capital.
These plant species are examples of nature’s pharmacy. Their scientific names (see Supplement 5, p. S18–S19) and some of their medicinal uses are shown as well. Parts of these plants as well as a number of other plant and animal species (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Once the active ingredients in the plants have been identified, scientists can usually produce them synthetically. The active ingredients in nine of the ten leading prescription drugs originally came from wild organisms. Many of the world’s tropical plant species are likely to become extinct before we can even study them. Question: Which of these species, if any, might have helped you or people you know to deal with health problems?
Figure 9.8: Many species of wildlife such as this endangered hyacinth macaw are sources of beauty and pleasure. This species of parrot is found in fairly open woodlands and swamps in several areas of Brazil, Bolivia, and Paraguay. This and other colorful species of parrots have become endangered because many birds have been removed from the wild and sold (sometimes illegally) as pets.
Figure 9.9: This figure illustrates both the underlying and direct causes of depletion and extinction of wild species resulting from human activities (Concept 9-3) (see Figure 1-9, p. 13). The biggest cause is habitat loss, degradation, and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive (nonnative) species into ecosystems. Question: What are two direct causes that are specifically related to each of the underlying causes?
Figure 9.10: Natural capital degradation.
These maps reveal the reductions in the ranges of four wildlife species, mostly as the result of severe habitat loss and fragmentation and illegal hunting for some of their valuable body parts. What will happen to these and millions of other species during the next few decades when the human population grows by at least 2 billion—the equivalent of more than 6 times the current U.S. population and almost twice the current population of China—as is projected by scientists? See an animation based on this figure at CengageNOW. Question: Would you support expanding these ranges even though this would reduce the land available for human habitation and farming? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)
Figure 9.10: Natural capital degradation.
These maps reveal the reductions in the ranges of four wildlife species, mostly as the result of severe habitat loss and fragmentation and illegal hunting for some of their valuable body parts. What will happen to these and millions of other species during the next few decades when the human population grows by at least 2 billion—the equivalent of more than 6 times the current U.S. population and almost twice the current population of China—as is projected by scientists? See an animation based on this figure at CengageNOW. Question: Would you support expanding these ranges even though this would reduce the land available for human habitation and farming? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)
Figure 9.10: Natural capital degradation.
These maps reveal the reductions in the ranges of four wildlife species, mostly as the result of severe habitat loss and fragmentation and illegal hunting for some of their valuable body parts. What will happen to these and millions of other species during the next few decades when the human population grows by at least 2 billion—the equivalent of more than 6 times the current U.S. population and almost twice the current population of China—as is projected by scientists? See an animation based on this figure at CengageNOW. Question: Would you support expanding these ranges even though this would reduce the land available for human habitation and farming? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)
Figure 9.10: Natural capital degradation.
These maps reveal the reductions in the ranges of four wildlife species, mostly as the result of severe habitat loss and fragmentation and illegal hunting for some of their valuable body parts. What will happen to these and millions of other species during the next few decades when the human population grows by at least 2 billion—the equivalent of more than 6 times the current U.S. population and almost twice the current population of China—as is projected by scientists? See an animation based on this figure at CengageNOW. Question: Would you support expanding these ranges even though this would reduce the land available for human habitation and farming? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)
Figure 9.11: These are some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States.
Figure 9.11: These are some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States.
Figure 9.12: Kudzu has taken over this abandoned house in the U.S. state of Mississippi. The vine, which can grow 5 centimeters (2 inches) per hour, was deliberately introduced into the United States for erosion control. Digging it up and burning it do not halt its spread. Grazing goats and repeated doses of herbicides can destroy it, but goats and herbicides also destroy other plants, and herbicides can contaminate water supplies. Scientists have found a common fungus that can kill kudzu within a few hours, apparently without harming other plants, but they need to investigate any harmful side effects it may have.
Figure 9.13: This huge python and an American alligator were in a life-or-death struggle in the Florida Everglades. After a 10-hour battle the alligator killed the snake by taking it underwater and drowning it. However, in some struggles, these snakes kill and eat the alligators—their only natural predator in the Everglades.
Figure 9.21: The Pelican Island National Wildlife Refuge in Florida was America’s first National Wildlife Refuge. It was established in 1903 to help protect the brown pelican (see photo insert) and other birds from extinction. In 2009, the brown pelican was removed from the U.S. endangered species list.
Figure 9.22: Individuals matter.
You can help prevent the extinction of species. Questions: Which two of these actions do you believe are the most important? Why?
