Transcript Topic 4.1 Biodiversity in ecosystems

CONSERVATION AND
BIODIVERSITY
4.1 Biodiversity in ecosystems
Assessment Statements
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4.1.1 Define the terms biodiversity, genetic
diversity, species diversity, and habitat diversity
4.1.2 Outline the mechanism of natural selection as
a possible driving force for speciation.
4.1.3 State that isolation can lead to different
species being produced that are unable to
interbreed to yield fertile offspring.
4.1.4 Explain how plate activity has influenced
evolution and biodiversity.
4.1.5 Explain the relationships among ecosystem
stability, diversity, succession and habitat.
4.1.1 Define the terms biodiversity, genetic diversity, species
diversity, and habitat diversity
Biodiversity: amount of
biological or living diversity
per unit area. Consists of
species, habitat, and
genetic diversity
 Genetic Diversity: Different
genetic characteristics of a
species.
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Cheetah populations have
very low diversity, due to
inbreeding
4.1.1 Define the terms biodiversity, genetic diversity, species
diversity, and habitat diversity
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Species diversity – the
variety of species per
unit area; includes the
number of species
present and their
relative abundance.
4.1.1 Define the terms biodiversity, genetic diversity, species
diversity, and habitat diversity
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Habitat Diversity: The amount of habitats or niches in a given
area
 Variety
of forests, deserts, grasslands, lakes, oceans,
coral reefs, wet lands, and other biological communities.
Chaparral
Coniferous forest
dessert
grasslands
deciduous forest
Biodiversity: Why should we care?
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Diverse ecosystems are more stable and more
healthy
More resistant to damage from factors like climate
change and spread of disease
Provides important ecological services to humans
Biodiversity is useful to us as humans
 Recreation
 Food
Goods
 Medicine
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Ecological Services of
Biodiversity
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Flow of material, energy in
the biosphere
 Photosynthesis
 Pollination
 Soil
formation and
maintenance
 Nutrient cycling
 Moderation of weather
extremes
 Purification of air and water
Important “stuff” From biodiversity
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Food, fuel, ecosystems, species, fiber, lumber,
paper….
90% of all food crops
40% of all medicines and 85% of all antibiotics
Willow Tree - Aspirin
Pacific Yew – Taxol
(cancer drug)
Biodiversity of Species
Each Species and Process…
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Is key to the overall function of earth
In general Diversity = Stability
Biodiversity is
 Nature’s
insurance policy against change
 The source of all natural capital for human use
 The way chemical materials are cycled and purified
 The end result of millions of years of evolution and
irreplaceable
China
Myanmar
India
Mexico
Costa Rica
Colombia
Ecuador
Peru
Venezuela
Cameroon
Zaire
Brazil
Philippines
Ethiopia
Malaysia
Indonesia
Madagascar
Australia
South Africa
The 19 Most Biodiverse countries in the world.
What is the Problem with this?
Caucasus
Mediterranean
basin
California
Floristic
Province
Mountains of south
central China
IndoBurma
Mesoamerican
forests
Philippines
Caribbean
Choco/Darien/
western Ecuador
Brazillian
Cerrado
Tropical
Andes
Polynesia and
Micronesia
island
complex
Polynesia
and
Micronesia
island
complex
Central
Chile
Brazil's
Atlantic
forests
Eastern Arc Mountains
and coastal forests
of Kenya and Tanzania
Guinean
forests of
West
Succulent
Africa
Karoo
Cape Floristic
region of
South Africa
Western
Ghats and
Sri Lanka
Wallacea
Sundaland
New
Caledonia
Madagascar/
Indian Ocean
islands
Southwest
Australia
New Zealand
Biodiversity Hotspots need special consideration
Hotspots
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These areas need emergency conservation attention
Especially rich in endemic plant and animal species (found
nowhere else in the world)
They cover on 1.4% of world land area
Mostly tropical forests
Contain 60% of identified terrestrial biodiversity
55% of all primates, 22% of all carnivores
1.1 billion people living in poverty near these sites
$500 million annually would go far to ensure their
preservation
Diversity includes
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2.
Richness: The number of
species per sample is a
measure of richness.
 The more species present in
a sample, the “richer” the
sample.
Evenness: A measure of the
relative abundance of the
different species making up
the richness of an area.
Which sample is more diverse?
Flower Species Sample 1
Sample 2
Daisy
300
20
Dandelion
335
49
Buttercup
365
931
Total
1000
1000
Which has a higher richness? Evenness?
Quantifiying this Diversity – Simpson’s
Index
D = N (N – 1)
∑ n (n – 1)
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Where
D = diversity index
N = total # of organisms of all species
n = # of individuals of particular species
Now practice the simpson’s index
Species
Number (n)
Woodrush
2
Holly seedlings
8
Bramble
1
Yorkshire Fog
1
Sedge
3
Total (N)
n (n – 1)
Now practice the simpson’s index
Species
Number (n)
Woodrush
2
Holly seedlings
8
Bramble
1
Yorkshire Fog
1
Sedge
3
Total (N)
15
n (n – 1)
Now practice the simpson’s index
Species
Number (n)
n (n – 1)
Woodrush
2
2
Holly seedlings
8
56
Bramble
1
0
Yorkshire Fog
1
0
Sedge
3
6
Total (N)
15
64
15(14) / 64 =3.28
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High values of “D” suggests a stable and ancient
site
A low value of “D” could suggest pollution, recent
colonization, or agricultural management
Index normally used in studies of vegetation but can
be applied to comparisons of diversity of any
species
How does diversity exist?
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Natural Selection = survival of the fittest
Fitness = a measure of reproductive success
If all individuals are variable
And populations produce large numbers of offspring
without increase in population size
And resources are limited
And traits are heritable
How does diversity exist?
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Those individuals who are best adapted to the
environment will survive and pass on their genes
Gradually the gene frequency in the population will
represent more of these “fit” individuals