《环境生态学Cha》PPT课件
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Chapter 7
Conserving Biological Resources
.
1
Chapter 7 Conserving Biological Resources
7.1 Value of Wild Species 7.2 Biodiversity
.
2
7.1 Value of Wild Species
7.1.1 Biological Wealth
About 1.75 million species of
plants, animals, and microbes have been examined, named, and classified, but scientists estimate that
.
16
The smallest population size needed to stay above the extinction vortex is often called the minimum viable population (MVP)
.
17
.
18
.
19
.
20
7.2.4 Reasons for Decline of Biodiversit
pollution
Biblioteka Baidu
Change biological environment:
2.Introduce new species
New predator
3. Overhunting
Big-game hunting
4. Secondary extinctions
Loss of food species
.
12
value ➢Intrinsic value
.
5
7.2 Biodiversity
7.2.1 Concept
Biodiversity: the variety and variability among
living organisms and the ecological complexes in which they occur Species diversity:
.
7
Figure 7.1 Preserving 50% of total habitat area often
leaves about 90% of the original species remaining alive
.
8
7.2.3 Extinction Species extinction:
.
13
.
14
.
15
Two basic causes for this extinction vortex
➢One is that small populations may have breeding problems. ➢The second cause is that small populations are much more easily wiped out by random environmental fluctuations
10
.
11
Table 7.3 Four ways that humans cause population decline and species extinction
Change physical environment: Examples
1.Habitat disruption
Drain swamp, toxic
Physical Alteration of Habitats
The Population Factor
Exotic Species
Overuse
.
21
.
22
7.2.5 Convention on Biological Diversity (1992 in Rio de Janeiro)
➢Adopt specific national biodiversity action plans and strategies ➢Establish a system of protected areas and ecosystems within the country ➢Establish policies that provide incentives to promote sustainable use of biological resources
the number of species that occur in an area
.
6
7.2.2 The species-area curve:
The number of species is counted in a gradually enlarged area of sampling, the result is a curve. The number of species rises rapidly at first, but it slows as the area of sampling increases because the same species are encountered again and again.
a species has died out in a local area
Ecological extinction:
a species has become so rare that it has essentially no role or impact on its ecosystem
.
9
.
.
4
The value of natural species
➢Sources for agriculture, forestry, aquaculture, and animal husbandry
➢Sources for medicines, pharmaceuticals ➢Recreational, aesthetic, and scientific
between 4 million and 112 million additional species have not
yet been systematically explored .
.
3
7.1.2 Two Kinds of Value
➢instrumental value: its existence or use benefits some other entity ➢intrinsic value: it has value for its own sake
Conserving Biological Resources
.
1
Chapter 7 Conserving Biological Resources
7.1 Value of Wild Species 7.2 Biodiversity
.
2
7.1 Value of Wild Species
7.1.1 Biological Wealth
About 1.75 million species of
plants, animals, and microbes have been examined, named, and classified, but scientists estimate that
.
16
The smallest population size needed to stay above the extinction vortex is often called the minimum viable population (MVP)
.
17
.
18
.
19
.
20
7.2.4 Reasons for Decline of Biodiversit
pollution
Biblioteka Baidu
Change biological environment:
2.Introduce new species
New predator
3. Overhunting
Big-game hunting
4. Secondary extinctions
Loss of food species
.
12
value ➢Intrinsic value
.
5
7.2 Biodiversity
7.2.1 Concept
Biodiversity: the variety and variability among
living organisms and the ecological complexes in which they occur Species diversity:
.
7
Figure 7.1 Preserving 50% of total habitat area often
leaves about 90% of the original species remaining alive
.
8
7.2.3 Extinction Species extinction:
.
13
.
14
.
15
Two basic causes for this extinction vortex
➢One is that small populations may have breeding problems. ➢The second cause is that small populations are much more easily wiped out by random environmental fluctuations
10
.
11
Table 7.3 Four ways that humans cause population decline and species extinction
Change physical environment: Examples
1.Habitat disruption
Drain swamp, toxic
Physical Alteration of Habitats
The Population Factor
Exotic Species
Overuse
.
21
.
22
7.2.5 Convention on Biological Diversity (1992 in Rio de Janeiro)
➢Adopt specific national biodiversity action plans and strategies ➢Establish a system of protected areas and ecosystems within the country ➢Establish policies that provide incentives to promote sustainable use of biological resources
the number of species that occur in an area
.
6
7.2.2 The species-area curve:
The number of species is counted in a gradually enlarged area of sampling, the result is a curve. The number of species rises rapidly at first, but it slows as the area of sampling increases because the same species are encountered again and again.
a species has died out in a local area
Ecological extinction:
a species has become so rare that it has essentially no role or impact on its ecosystem
.
9
.
.
4
The value of natural species
➢Sources for agriculture, forestry, aquaculture, and animal husbandry
➢Sources for medicines, pharmaceuticals ➢Recreational, aesthetic, and scientific
between 4 million and 112 million additional species have not
yet been systematically explored .
.
3
7.1.2 Two Kinds of Value
➢instrumental value: its existence or use benefits some other entity ➢intrinsic value: it has value for its own sake