Transcript CHAPTER 60 LECTURE SLIDES Prepared by Brenda Leady

CHAPTER 60
LECTURE
SLIDES
Prepared by
Brenda Leady
University of Toledo
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
Biodiversity can be examined at 3 levels
 _____________–
amount of genetic variation that
occurs within and between populations
 _____________– threatened species are likely to
become endangered, endangered species are in
danger of extinction
 _____________– diversity of structure and function
within an ecosystem
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Conservation biology protects
______________________at all levels
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3
Why conserve biodiversity?
1.
2.
3.
4
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Economic values
 Zea
diploperenis, an ancient ______ relative, is
resistant to many corn viruses and its genes are
being used to develop resistant corn
 25%
of prescription drugs in the US are derived from
_______
 Desert
pupfishes are models for research on human
_______ disease

World’s ecosystems worth more than $_______
a year
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How much diversity for proper function?
 _____
hypothesis linking diversity and stability
suggests a linear correlation between
diversity and ecosystem function
 ______ hypothesis – species are like rivets
with each playing a small critical role
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hypothesis – most species are
redundant, they take up space but do not add to
diversity, but keystone species are vital to function
 _________ hypothesis – ecosystem function can
change as the number of species increases or
decreases but the direction of change is not
predictable
 __________
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Ecotron Experiments Showed the Relationship
Between Biodiversity and Ecosystem Function
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14 environmental chambers used to replicate
terrestrial communities
Differed only in biodiversity
Each had 4 trophic levels
Analyzed a range of measures of ecosystem
function – community respiration, decomposition,
nutrient retention rates, and productivity
Community productivity, % change in vegetation
cover, increased as species richness increased
First experimental demonstration that loss of
biodiversity can impair ecosystem function

Field experiments
 Plots
sown with up to 24 species of native
prairie plants
 Results showed again that more diverse plots
had increased productivity and used nutrients
more efficiently than less diverse ones
 Frequency of invasive plant species and foliar
fungal diseases decreased with increased
richness
 ___________ species richness increased with
plant species richness
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Causes of extinction and loss of biodiversity
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Extinction is a natural process
 Average
life span of a species in the fossil record is
around 4 million years
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Background extinction is 1 species every
______ years
May be higher at 1 or 2 every 100 years
Biodiversity crisis – in the past 100 years 20
species of ____________ and over 40 species
of __________ have gone extinct
Growth of __________ population linked to
number of extinctions
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60
6
50
5
40
4
Birds
Mammals
30
3
20
2
10
1
0
0
1600–1700
1700–1800
1800–1900
Year
Number of humans (billions)
Number of extinct species
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1900–2000
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Main causes of extinction

Species moved by humans from a native location
to another location
 Invasive species – out compete native species for
space and resources
 3 categories of interaction
 Competition – not shown to cause extinction
 Predation – rats, cats and mongoose account
for 43% of recorded bird extinctions
 Disease – 50% of native Hawaiian birds extinct
due to avian malaria
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
Passenger pigeon and Carolina parakeet hunted
to extinction by the early 20th century
 Whale species driven to the brink of extinction prior
to a 1988 moratorium on commercial whaling
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Deforestation a prime cause of extinction
 Ivory-billed woodpecker assumed extinct due to
logging (unconfirmed sighting in 2004)
 Planting agricultural crops and urbanization also
destroy habitat
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 Human-induced
climate change, or global
warming, has been implicated in the dramatic
decrease in the population sizes of frog
species in Central and South America
 Unless greenhouse gas emissions are cut
drastically, climate change will cause 15–37%
of the species 6 biodiversity-rich regions to go
extinct by the year 2050
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 Inbreeding
– mating among relatives
More likely when population small
 Survivorship of offspring can decline
 Greater prairie chicken – reduced to population
with 5 or 6 males, resulted in steady reduction of
hatching success, brought in Kansas birds to
increase diversity
 Extinction vortex
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 Genetic
drift
Random change in allele frequency attributable to
chance
 Allee effect – some individuals fail to mate by
chance
 Small isolated populations more prone
 Lose a percentage of original diversity at 1/(2N)
per generation, N=population size
 Can be countered with immigration
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
 Number
of individuals that contribute genes
to future populations
 May be _________ than number of
individuals in ____________
 ________ mating structure – a few males
command all the breedings
 In
a population of 250 males and 250 females
 Ne is 100% of all individuals breed
 Ne is 8% if 10 males breed with 250 females
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Grizzly bears need
large population sizes
Effective population
size is 25% (not all
bears breed)
Even fairly large,
isolated populations
are vulnerable to the
harmful effects of loss
of genetic variation
North
Selkirks
Cascades
Cabinet
Yaak
Northern
Continental
Divide
Bitterroot
Yellowstone
Distribution in 1850
Current distribution
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Conservation strategies

Habitat conservation focuses on
 _____________________–
greatest number
of species
Just 17 countries are home to nearly 70% of all
known species
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top the list
 Do not necessarily contain the most unique
species – 208 mammal species are shared
between Peru and Ecuador (part of the 17)
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 Areas
rich in endemic species
_______________ are found only in a particular
place and nowhere else
 _____________ have the widest variety of
endemic species with at least 1500 species of
vascular plants and lost 70% of original habitat
 34 hot spots occupy only 2.3% of Earth’s surface
but contain 150,000 endemic plant species (50%
of world total)
 __________________ are rich in endemics and
may receive more attention/funding at the expense
of other areas
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
75º
60º
Latitude
45º
30º
15º
California
Floristic
Province
0º
15º
30º
45º
60º
Polynesia/
Micronesia
Mediterranean
Basin
IranoAnatolian Caucasus
Madrean
pine-oak
woodlands
Mountains of
Central Asia
South Central
China
Japan
Horn of IndoPhilippines
Eastern Africa Burma Himalaya
Brazil’s
Afromontane
Mesoamerica
Cerrado
Wallacea
Western
Tropical
Choco/
Melanesian Islands
Ghats and
West
Andes
Darien/
Sri Lanka
African
Western
Sundaland
New
forests
Ecuador
Caledonia
Madagascar
Succulent
Central
Coastal
Brazil’s
Southwest
Karoo
Chile
Cape
forests
Atlantic
Australia
Floristic of Eastern
Forest
New Zealand
Province Africa
Caribbean
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 While
the Pampas of South America does
not compare well to the richness or
endemics of the rain forest, it is a unique
area that without preservation could
disappear
 Many areas that are threatened but not
biologically rich may be preserved in
addition to the less immediately threatened,
but richer, tropical forests
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Theory and practice of reserve design
 Principles
of island biogeography
Wildlife reserves and sanctuaries are __________
 The _______ the area, the _________ number of
species would be protected
 SLOSS debate – single large reserve may be able
to preserve a larger population or several smaller
ones may contain a broader variety of habitats and
a reduced risk to fire or disease
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Better
Worse
(a) Large or small
(b) Single large or
several small
(c) Close or far
(d) Clustered or linear
(e) Linked or separate (f) Round or oblong
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 Principles
of landscape ecology
Examines the spatial arrangement of elements in
communities and ecosystems
 Link small reserves with ___________ or
_________________
 Hedgerows in Europe function as corridors
between forest fragments
 In China, corridors of habitat link small, adjacent
population of giant pandas
 Parks are often designed to minimize edge effects
so circular parks are preferred over long, skinny
parks
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Economic considerations
 Principles
of island biogeography and
landscape ecology useful
 Economic considerations often enter in the
choice of areas to preserve
 In Africa, several large parks contain sizable
populations
In the 1980s, populations of black rhino and
elephant declined due to poaching
 Rates of decline in elephants and rhinos were
more linked to conservation efforts and spending
than to land area
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Single-species approach
 ___________________________–
species
whose status confirms the overall health of an
ecosystem
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Corals are good indicators of …
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Proliferation of the dark variety of the peppered
moth (Bistonbetularia) has been shown to be a
good indicator of air pollution
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Polar bears are an indicator for …
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Single-species approach
 ___________________–
habitat requirements are so
large that protecting them also protects many other
species in the same habitats
 A Northern spotted owl pair needs 800 hectares of
old-growth forest for survival and reproduction
 To protect Zea diploperennis, the land where it
grows was bought and a nature reserve
established
 _______________________– single large or instantly
recognizable species
 Attractive and engender public support
 American buffalo, giant panda, Florida panther
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___________________ – species within a
community that have a role out of proportion with
their abundance
 Beaver
can completely alter a community by building
a dam and flooding an entire river valley
 Palm nuts and figs produce fruit during otherwise
fruitless times and are critical resources
 Not a dominant species – one that has a large effect
in a community because of its abundance or high
biomass
 Gopher tortoises and beavers are also ecosystem
engineers – create, modify and maintain habitats
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 Full
or partial repair or replacement of
biological habitats and/or their populations
that have been damaged
 Can restore or rehabilitate a habitat
 Can return species to the wild following
captive breeding
 Bioremediation – use of living organisms to
detoxify polluted habitats
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Habitat restoration
3
basic approaches
____________________ – attempt to put back
exactly what was there prior to disturbance
 ___________________ – return habitat to
something similar but less than full restoration
 ___________________– replaces original
ecosystem with a different one – deciduous forest
replaced after mining by grassland
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 use
of living organisms, usually microbes or
plants, to detoxify polluted habitats such as
dump sites or oil spills
 Some bacteria can detoxify contaminants
 Certain plants can accumulate toxins in their
tissues and are then harvested, removing the
poison from the system
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 Propagation
of animals and plants outside
their natural habitat to produce stock for
subsequent release into the wild
 Mid-1960s peregrine falcon became extinct in
eastern US due to DDT effects
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In 1999 removed from Endangered Species List
 California
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condors were down to 22 birds
2002 milestone – pair of captive-reared birds bred
in wild
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Can Cloning Save Endangered Species?
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1997, Dolly the cloned sheep announced
Cow gave birth to a cloned Asian gaur from a single
skin cell from a dead gaur
Javan banteng successfully cloned in 2003
In 2005, clones of African wildcat successfully bred
Unresolved issues
 Reproductive knowledge needed is immense
 Identify surrogate mothers of other species
does not address the root cause of loss – habitat
fragmentation or poaching
 May or may not be able to reintroduce genetic variability
lost with deceased animals
 Cloning