1. Overview: Striking Gold
1.8 million species have been identified
Biologists estimate 10–200 million species exist
Tropical forests contain some of the greatest concentrations of species and are being destroyed at an alarming rate
Humans are rapidly pushing many species toward extinction
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2. What will be the fate of this newly described bird species?
Figure 56.1

3. Tropical deforestation in West Kalimantan, an Indonesian province.
Figure 56.2 Tropical deforestation in West Kalimantan, an Indonesian province.

4. Conservation Biology and Global Change
Chapter 56

5. Conservation biology Seeks to preserve life, integrates several fields
Ecology
Physiology
Molecular biology
Genetics
Evolutionary biology
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6. Human activities threaten Earth’s biodiversity
Rates of species extinction are difficult to determine under natural conditions
The high rate of species extinction is largely a result of ecosystem degradation by humans
Humans are threatening Earth’s biodiversity
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7. Three Levels of Biodiversity
Biodiversity has three main components
Genetic diversity
Species diversity
Ecosystem diversity
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8. Genetic diversity in a vole population Species diversity in a coastal
Figure 56.3
Genetic diversity
in a vole population
Species diversity
in a coastal
redwood ecosystem
Figure 56.3 Three levels of biodiversity.
Community and
ecosystem diversity
across the
landscape of
an entire region

9. Genetic Diversity
Genetic diversity comprises genetic variation within a population and between populations
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10. Species Diversity
Species diversity is the variety of species in an ecosystem or throughout the biosphere
According to the U.S. Endangered Species Act
An endangered species is “in danger of becoming extinct throughout all or a significant portion of its range”
A threatened species is likely to become endangered in the foreseeable future
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11. Extinction may be local or global
Conservation biologists are concerned about species loss because of alarming statistics regarding extinction and biodiversity
Globally, 12% of birds, 20% of mammals, and 32% of amphibians are threatened with extinction
Extinction may be local or global
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12. A hundred heartbeats from extinction.
Figure 56.4
Philippine eagle
A hundred heartbeats from extinction.
Yangtze River
dolphin
Figure 56.4
Javan
rhinoceros

13. Ecosystem Diversity
Human activity is reducing ecosystem diversity, the variety of ecosystems in the biosphere
More than 50% of wetlands in the contiguous United States have been drained and converted to other ecosystems
The local extinction of one species can have a negative impact on other species in an ecosystem
For example, flying foxes (bats) are important pollinators and seed dispersers in the Pacific Islands
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14. The endangered Marianas “flying fox” bat (Pteropus mariannus),
an important pollinator.
Figure 56.5

15. Benefits of Species and Genetic Diversity
Species related to agricultural crops can have important genetic qualities
Plant breeders bred virus-resistant commercial rice by crossing it with a wild population
In the United States, 25% of prescriptions contain substances originally derived from plants
The rosy periwinkle contains alkaloids that inhibit cancer growth
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16. The rosy periwinkle (Catharanthus roseus)
Figure 56.6
The rosy periwinkle (Catharanthus roseus)
Figure 56.6

17. The loss of species also means loss of genes and genetic diversity
The enormous genetic diversity of organisms has potential for great human benefit
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18. Ecosystem Services
Ecosystem services encompass all the processes through which natural ecosystems and their species help sustain human life
Some examples of ecosystem services
Purification of air and water
Detoxification and decomposition of wastes
Cycling of nutrients
Moderation of weather extremes
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19. Threats to Biodiversity
Most species loss can be traced to four major threats
Habitat destruction
Introduced species
Overharvesting
Global change
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20. Habitat Loss
Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere
In almost all cases, habitat fragmentation and destruction lead to loss of biodiversity
For example
In Wisconsin, prairie occupies <0.1% of its original area
About 93% of coral reefs have been damaged by human activities
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21. Habitat fragmentation in the foothills of Los Angeles.
Figure 56.7
Habitat fragmentation in the foothills of Los Angeles.
Figure 56.7

22. Introduced Species
Introduced species are those that humans move from native locations to new geographic regions
Without their native predators, parasites, and pathogens, introduced species may spread rapidly
Introduced species that gain a foothold in a new habitat usually disrupt their adopted community
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23. Sometimes humans introduce species by accident
The brown tree snake arrived in Guam as a cargo ship “stowaway” and led to extinction of some local species
Humans have deliberately introduced some species with good intentions but disastrous effects
Kudzu was intentionally introduced to the southern United States
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24. (a) Brown tree snake (b) Kudzu Figure 56.8
Figure 56.8 Two introduced species.
(b) Kudzu

25. Overharvesting
Overharvesting is human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound
Large organisms with low reproductive rates are especially vulnerable to overharvesting
Elephant populations declined because of harvesting for ivory
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26. DNA analysis can help conservation biologists identify the source of illegally obtained animal products
DNA from illegally harvested ivory can be used to trace the original population of elephants to within a few hundred kilometers
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27. Overfishing has decimated wild fish populations
North Atlantic bluefin tuna has decreased by 80% in ten years
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28. Global Change
Global change includes alterations in climate, atmospheric chemistry, and broad ecological systems
Acid precipitation contains sulfuric acid and nitric acid from the burning of wood and fossil fuels
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29. Acid Rain
Air pollution from one region can result in acid precipitation downwind
For example, industrial pollution in the midwestern United States caused acid rain in eastern Canada in the 1960s
Acid precipitation kills fish and other lake-dwelling organisms
Environmental regulations have helped to decrease acid precipitation
For example, sulfur dioxide emissions in the United States decreased 31% between 1993 and 2002
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30. Changes in the pH of precipitation at Hubbard Brook, New Hampshire.
4.7
4.6
4.5
4.4 pH
4.3
4.2
Figure 56.11
4.1
4.0
1960
‘65
‘70
‘75
‘80
‘85
‘90
‘95
2000
‘05
‘10
Year

31. Population conservation focuses on population size, genetic diversity, and critical habitat
Biologists focusing on conservation at the population and species levels follow two main approaches
The small-population approach
The declining-population approach
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32. Small-Population Approach
The small-population approach studies processes that can make small populations become extinct
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33. The Extinction Vortex: Evolutionary Implications of Small Population Size
A small population is prone to inbreeding and genetic drift that draw it down an extinction vortex
The key factor driving the extinction vortex is loss of the genetic variation necessary to enable evolutionary responses to environmental change
Small populations and low genetic diversity do not always lead to extinction
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34. Processes driving an extinction vortex.
Figure 56.12
Small
population
Processes driving an extinction vortex.
Genetic
drift
Inbreeding
Lower
reproduction
Higher
mortality
Loss of
genetic
variability
Figure 56.12
Reduction in
individual
fitness and
population
adaptability
Smaller
population

35. Case Study: The Greater Prairie Chicken and the Extinction Vortex
Populations of the greater prairie chicken were fragmented by agriculture and later found to exhibit decreased fertility
To test the extinction vortex hypothesis, scientists imported genetic variation by transplanting birds from larger populations
The declining population rebounded, confirming that low genetic variation had been causing an extinction vortex
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36. Figure 56.13
RESULTS
200
What caused the drastic decline of the Illinois greater prairie chicken population?
150
Number of male birds
100
Translocation 50
1970
1975
1980
1985
1990
1995
Year
(a) Population dynamics
100 90 80 70 60 50 40 30
Figure Inquiry: What caused the drastic decline of the Illinois greater prairie chicken population?
Eggs hatched (%)
1970–‘74
‘75–‘79
‘80–‘84
‘85–‘89
‘90
‘93–‘97
Year
(b) Hatching rate

37. Minimum Viable Population Size
Minimum viable population (MVP) is the minimum population size at which a species can survive
The MVP depends on factors that affect a population’s chances for survival over a particular time
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38. Effective Population Size
A meaningful estimate of MVP requires determining the effective population size, which is based on the population’s breeding potential
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39. Ne = Nf + Nm Effective population size Ne is estimated by 4NfNm
where Nf and Nm are the number of females and the number of males, respectively, that breed successfully
Viability analysis is used to predict a population’s chances for survival over a particular time interval
4NfNm
Nf + Nm
Ne =
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40. Case Study: Analysis of Grizzly Bear Populations
One of the first population viability analyses was conducted as part of a long-term study of grizzly bears in Yellowstone National Park
It is estimated that a population of 100 bears would have a 95% chance of surviving about 200 years
This grizzly population is about 400, but the Ne is about 100
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41. Figure 56.14
Figure Long-term monitoring of a grizzly bear population.

42. The Yellowstone grizzly population has low genetic variability compared with other grizzly populations
Introducing individuals from other populations would increase the numbers and genetic variation
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43. Declining-Population Approach
Focuses on threatened and endangered populations that show a downward trend, regardless of population size
Emphasizes the environmental factors that caused a population to decline
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44. Steps for Analysis and Intervention
Declining-population approach involves several steps
Confirm that the population is in decline
Study the species’ natural history
Develop hypotheses for all possible causes of decline
Test the hypotheses in order of likeliness
Apply the results of the diagnosis to manage for recovery
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45. Case Study: Decline of the Red-Cockaded Woodpecker
Red-cockaded woodpeckers require living trees in mature pine forests
These woodpeckers require forests with little undergrowth
Logging, agriculture, and fire suppression have reduced suitable habitat
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46. A habitat requirement of the red-cockaded woodpecker.
Figure 56.15
A habitat requirement of the red-cockaded woodpecker.
Red-cockaded woodpecker
Figure 56.15
(a) Forests with low undergrowth
(b) Forests with high, dense undergrowth

47. They have a complex social structure where one breeding pair has up to four “helper” individuals
Individuals often have a better chance of reproducing by helping and waiting for an available cavity, instead of excavating new cavities
In a study where breeding cavities were constructed, new breeding groups formed only in these sites
Based on this experiment, a combination of habitat maintenance and excavation of breeding cavities enabled this endangered species to rebound
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48. Weighing Conflicting Demands
Conserving species often requires resolving conflicts between habitat needs of endangered species and human demands
For example, in the U.S. Pacific Northwest, habitat preservation for many species is at odds with timber and mining industries
Managing habitat for one species might have positive or negative effects on other species
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49. Landscape and regional conservation help sustain biodiversity
Conservation biology attempts to sustain biodiversity of entire communities, ecosystems, and landscapes
Ecosystem management is part of landscape ecology, which seeks to make biodiversity conservation part of land-use planning
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50. Landscape Structure and Biodiversity
Structure of landscape can strongly influence biodiversity
(a) Natural edges
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(b) Edges created by human activity

51. Fragmentation and Edges
Boundaries, or edges, between ecosystems are defining features of landscapes
Some species take advantage of edge communities to access resources from both adjacent areas
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52. Biological Dynamics of Forest Fragments Project in Amazon examines effects of fragmentation on biodiversity
Landscapes dominated by fragmented habitats support fewer species due to loss of species adapted to habitat interiors
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53. Corridors That Connect Habitat Fragments
Movement corridor = narrow strip of quality habitat connecting isolated patches
Movement corridors promote dispersal and help sustain populations
Artificial corridors are sometimes constructed
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54. Establishing Protected Areas
Conservation biologists apply understanding of ecological dynamics in establishing protected areas to slow the loss of biodiversity
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55. Preserving Biodiversity Hot Spots
Biodiversity hot spot = relatively small area with great conc. of endemic species and many endangered and threatened species
Good choices for nature reserves, but identifying them is not always easy
Designation of hot spots often biased toward saving vertebrates and plants
Hot spots can change with climate change
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56. Earth’s terrestrial and marine biodiversity hot spots.
Figure 56.19
Earth’s terrestrial and marine biodiversity hot spots.
Terrestrial biodiversity
hot spots
Marine biodiversity
hot spots
Equator
Figure 56.19

57. Philosophy of Nature Reserves
Biodiversity “islands” in sea of habitat degraded by human activity
Must consider disturbances as functional component of all ecosystems
Important question: create fewer large reserves or more numerous small reserves?
Argument for large reserves – large, far-ranging animals with low-density populations require extensive habitats
Smaller reserves may be more realistic, and may slow spread of disease throughout population
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58. Figure 56.20 50
100
Biotic boundaries for grizzly bears in Yellowstone and Grand Teton National Parks.
Kilometers
ows R.
Yell
tone
MONTANA ne
Sho
sho R.
WYOMING
Yellowstone
National
Park
MONTANA
IDAHO
Figure 56.20
Grand Teton
National Park
Snake R.
Biotic boundary for
short-term survival;
MVP is 50 individuals.
IDAHO
WYOMING
Biotic boundary for
long-term survival;
MVP is 500 individuals.

59. Zoned Reserves
Zoned reserve model – conservation often involves working in landscapes that are human-dominated
Includes relatively undisturbed areas and modified areas that surround them as buffer zones
Zoned reserves are often established as “conservation areas”
Costa Rica – a world leader in zoned reserves
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60. Zoned reserves in Costa Rica.
Figure 56.21
Nicaragua
CARIBBEAN SEA
Zoned reserves in Costa Rica.
Costa
Rica
National park land
Buffer zone
Pan
ama
PACIFIC OCEAN
(a) Zoned reserves in Costa Rica
Figure 56.21
(b) Tourists in one of Costa Rica’s zoned reserves

61. Zoned reserves in Fiji islands are closed to fishing, which improves fishing success in nearby areas
United States has similar zoned reserve system – Florida Keys National Marine Sanctuary
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62. GULF OF MEXICO FLORIDA Florida Keys National Marine Sanctuary 50 km
Figure 56.22
GULF OF MEXICO
FLORIDA
Florida Keys National
Marine Sanctuary
50 km
Figure A diver measuring coral in the Florida Keys National Marine Sanctuary.

63. Earth is changing rapidly as a result of human actions
Locations of preserves today may be unsuitable for their species in the future
Human-caused changes
Nutrient enrichment
Accumulations of toxins
Climate change
Ozone depletion
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64. Nutrient Enrichment
In addition to transporting nutrients from one location to another, humans have added new materials, some of them toxins, to ecosystems
Harvest of crops exports nutrients from agricultural ecosystem
Agriculture leads to depletion of nutrients in soil
Fertilizers add nitrogen, etc. to agricultural ecosystem
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65. Critical load = amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity
Nutrients that exceed critical load leach into groundwater or run off into aquatic ecosystems
Agricultural runoff and sewage lead to phytoplankton blooms in Atlantic Ocean
Decomposition of phytoplankton blooms causes “dead zones” due to low oxygen levels
Winter
Summer
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66. Toxins in Environment
Humans release many toxic chemicals, including synthetics
Substances can persist for long periods
Toxins pften become more concentrated in successive trophic levels
Biological magnification concentrates toxins at higher trophic levels, where biomass is lower
PCBs and DDT
Herring gulls of Great Lakes lay eggs with PCB levels 5,000 times greater than in phytoplankton
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67. Biological magnification of PCBs in a Great Lakes food web
Figure 56.25
Biological magnification of PCBs in a Great Lakes food web
Herring gull eggs
124 ppm
Concentration of PCBs
Lake trout
4.83 ppm
Smelt
1.04 ppm
Figure
Zooplankton
0.123 ppm
Phytoplankton
0.025 ppm

68. Silent Spring
1960s – Rachel Carson brought attention to DDT in birds in Silent Spring
DDT banned in US in 1971
Countries with malaria face trade-off between killing mosquitoes and protecting other species
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69. Greenhouse Gases and Global Warming
Due to burning of fossil fuels and other human activities, conc. of atmospheric CO2 has been steadily increasing
Most plants grow faster with CO2 concentrations increase
C3 plants (wheat and soybeans) are more limited by CO2 than C4 plants (corn)
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70. Figure 56.27
Increase in atmospheric carbon dioxide concentration at Mauna Loa, Hawaii, and average global temperatures.
14.9
14.8
14.7
14.6
14.5
14.4
14.3
14.2
14.1
14.0
13.9
13.8
13.7
13.6
390
380
370
360
350
340
330
320
310
300
Temperature
CO2 concentration (ppm)
Average global temperature (°C)
CO2
Figure 56.27
Year

71. FACTS-I Experiment
Testing how elevated CO2 influences tree growth, carbon conc. in soils, insect populations, soil moisture, etc.
CO2-enriched plots produced more wood than control plots, though less than expected
Availability of nitrogen and other nutrients appears to limit tree growth and uptake of CO2
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72. Greenhouse Effect and Climate
CO2, water vapor, & other greenhouse gases reflect infrared radiation back toward Earth
Important for keeping Earth habitable
Increasing conc. of atmospheric CO2 is linked to increasing global temperature
Climatologists make inferences about past climates
Pollen & fossil plant records reveal past vegetation
CO2 levels inferred from bubbles trapped in glacial ice
Isotope analysis used to infer past temperature
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73. Warming trend would affect geographic distribution of precipitation
Northern coniferous forests and tundra show strongest effects of warming
2007 – extent of Arctic sea ice was smallest on record
Warming trend would affect geographic distribution of precipitation
Many organisms may not be able to survive rapid climate change
Some ecologists support assisted migration, translocation of species to favorable habitat beyond its native range
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74. Stabilizing CO2 emissions requires international effort
Global warming can be slowed by reducing energy needs & converting to renewable energy
Stabilizing CO2 emissions requires international effort
Recent international negotiations have yet to reach consensus on global strategy
Reduced deforestation would decrease greenhouse gases
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75. Depletion of Atmospheric Ozone
Earth protected from damaging effects of UV radiation by protective layer of ozone molecules in atmosphere
Ozone layer has been gradually thinning since mid-1970s
Mainly from chlorofluorocarbons (CFCs) produced by human activity
Chlorine reacts with ozone to make O2
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76. Ozone layer thickness (Dobsons)
Figure 56.29
Thickness of the October ozone layer over Antarctica in units called Dobsons.
350
300
250
200
150
100
Ozone layer thickness (Dobsons)
Figure 56.29
1955 ‘60
‘65 ‘70 ‘75
‘80
‘85
‘90 ‘ ‘05 ‘10
Year

77. Chlorine atom O2 Chlorine O3 CIO O2 CIO CI2O2 Sunlight
Figure 56.30
How free chlorine in the atmosphere destroys ozone.
Chlorine atom O2
Chlorine O3
CIO O2
CIO
Figure 56.30
CI2O2
Sunlight

78. Ozone thinnest over Antarctica and southern Australia, New Zealand, South America
Ozone levels have decreased 2–10% at mid-latitudes during past 20 years
September 1979
September 2009
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79. Ozone depletion causes DNA damage in plants and poorer phytoplankton growth
International agreement signed in 1987 has resulted in decrease in ozone depletion
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80. Concept 56.5: Sustainable development
Concept of sustainability helps ecologists establish long-term conservation priorities
Sustainable development: meets needs of people today without limiting ability of future generations to meet their needs
Sustainable Biosphere Initiative – define & acquire basic ecological information for responsible development, management, & conservation of Earth’s resources
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81. Case Study: Sustainable Development in Costa Rica
Partnerships between government, nongovernmental organizations (NGOs), and citizens
Human living conditions (infant mortality, life expectancy, literacy rate) in Costa Rica have improved along with conservation
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82. Life expectancy (years) Infant mortality (per 1,000 live births)
Figure 56.32
200
150
100 50 80 70 60 50 40 30
Life expectancy
Infant mortality
Life expectancy (years)
Infant mortality (per 1,000 live births)
Figure Infant mortality and life expectancy at birth in Costa Rica.
Year

83. Future of Biosphere Our lives differ greatly from early humans
Our behavior reflects remnants of our ancestral attachment to nature and diversity of life—the concept of biophilia (E.O. Wilson)
Connection to nature may motivate realignment of our environmental priorities
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84. Biophilia, past and present.
Figure 56.33
Biophilia, past and present.
(a) Detail of animals in a 36,000-
year-old cave painting,
Lascaux, France
(b) A 30,000-year-old ivory
carving of a water bird,
found in Germany
Figure 56.33
(c) Nature lovers on a wildlife-
watching expedition
(d) A young biologist holding
a songbird