BIOL 1120 Lecture Notes - Lecture 25: Keystone Species, Habitat Destruction, Hectare

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31 May 2016
Chapter 59: Conservation Biodiversity
I. Conservation biology and Biodiversity
A. ________________________ is a new discipline studying aspects of biodiversity in order to conserve natural resources.
1. Conservation biology involves both scientific concepts and their application to practical problems.
2. It supports 4 ethical principles :
a. Biodiversity is desirable for both the biosphere and for humans.
b. Extinctions due to human actions are undesirable.
c. The complex interactions in ecosystems support biodiversity and are therefore desirable.
d. Biodiversity from evolutionary change has value by itself regardless of any practical benefit.
3. Estimates vary but at least 10–20% of all species now living will most likely become extinct in 20–50 years.
4. Bioinformatics
a. The collecting and analyzing of biological information
b. Used in the study of conservation biology
B. ________________
1. Is the variety of life on Earth; it is generally described as the number of species of the various groups of
2. Most estimates place the number of species living on earth as between 10 and 50 million species; most are yet
to be found and described.
3. A ___________________ is one that is likely to become an __________________ (in danger of immediate
extinction) in the foreseeable future
4. Biodiversity also includes genetic diversity, community diversity, and landscape diversity.
a. ___________________ helps maintain reproductive vitality and assists adaptation.
i. The 1846 potato blight in Ireland was due to too little genetic diversity.
ii. 1922 saw a similar Soviet wheat failure.
iii. Florida had an outbreak of citrus canker in 1984 made worse by limited genetic variation.
iv. Such limited genetic variation creates the risk of extinction in natural populations.
b. _____________________ refers to the variation in species composition in a community.
i. Different communities have different species; therefore different communities add to species
ii. Attempts to save just one species are shortsighted when the community itself is threatened.
iii. Disrupting a community can threaten many species.
c. ______________________
i. Incorporates a number of interacting ecosystems within one landscape .
Rivers, etc.
ii. Fragmented landscapes reduce reproductive capacity, food availability, and affect seasonal behavior.
5. Distribution of Biodiversity
a. Biodiversity is not evenly distributed; saving some areas saves more species than saving others.
b. Biodiversity is highest in the tropics and declines toward the poles on land, in fresh water, and in the
c. Biodiversity hotspots contain unusually large concentrations of species; hotspots cover only about 1.4%
of Earth’s land area but contain 44% of the higher plant species and 35% of the terrestrial vertebrate
d. Madagascar, the Cape of South Africa, and the Great Barrier Reef of Australia are all biodiversity
e. Biodiversity frontiers such as the rain forest canopies and the deep sea benthos have more species than
formerly suspected.
II. Value of Biodiversity
A. Direct Value
1. ___________________ (Fig. 59.6, p. 1261)
a. Most U.S. prescription drugs were originally derived from living organisms.
a. The rosy periwinkle from Madagascar provides chemicals that treat the two cancers: leukemia and
Hodgkin disease.
a. Based on the past rate of drug discovery, there are perhaps 328 more drugs likely to be found in tropical
rain forests with $147 billion value.
a. Fungi and soil bacteria have provided penicillin, tetracycline, and streptomycin.
a. The nine-banded armadillo is the only other animal to contract human leprosy; this allowed research to
find a cure.
a. The blood of horseshoe crabs contains limulus amoebocyte lysate that keeps pacemakers free of bacteria.
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Chapter 59: Conservation Biodiversity
2. _______________________
a. Wheat, corn and rice crops are uniform; when devastated by pests, the wild strains they came from are a
source of genes for disease resistance.
b. When rice crops were devastated by a virus in Africa, it was necessary to locate a wild rice plant that
was resistant and breed the gene into the high yield rice.
c. Biological pest controls are economically important replacements when pests are pesticide-resistant.
d. Most flowering plants are pollinated by animals (e.g., bees, wasps, butterflies, birds, bats, etc.).
e. The honeybee is a multi-faceted example.
i. Domesticated bees pollinate over $10 billion worth of food crops annually.
ii. Tracheal mites have wiped out more than 20% of commercial honeybees in the U.S.
iii. Any hope for a resistant bee depends on wild bees; wild pollinators provide a $4.1 to $6.7 billion
service each year.
3. Consumptive Use Value
a. The cultivation of crops and domestication of animals (farming) have been successful enterprises.
b. However, fishing of wild species has not yet been replaced by aquaculture.
c. Harvesting wild fruits, vegetables, skins, fibers, beeswax, seaweed, and hunting meat are important to
many peoples.
d. Calculations show that the timber harvested from the natural environment in the Peruvian Amazon is of
less value than harvest of tree fruits and rubber production.
B. Indirect Value
1. Biogeochemical Cycles
a. Biodiversity contributes to the water, carbon, nitrogen, and phosphorus cycles of our ecosystem.
b. We depend upon normal cycles to provide fresh water, remove carbon dioxide, etc.
c. Technology cannot artificially create these cycles in place of the ecosystem.
2. Waste Disposal
a. Decomposers break down organic matter and other wastes into nutrients used by producers.
b. Decomposition in nature is more economical and complete than sewage treatment.
c. Biological communities purify water and break down pollutants; Canada estimates this wetland value at
$50,000 per hectare.
3. Provision of Fresh Water
a. Most terrestrial organisms, including humans, need freshwater ecosystems.
b. Desalination plants cost four to eight times the average cost of water taken from the water cycle.
c. Forests are “sponges that hold and release water over time; the value of marshland outside of Boston,
Massachusetts, is estimated at $72,000 per hectare based on its ability to reduce floods.
4. Prevention of Soil Erosion
a. Intact ecosystems naturally retain soil and prevent erosion.
b. Deforestation results in silt that fills reservoirs and denudes hillsides; a dam in Pakistan is filling much
faster due to silt.
c. Silt from deforestation also smothers mangrove and coastal ecosystems and ruins fisheries.
5. Regulation of Climate
a. Trees provide both shade and natural air conditioning.
b. Globally, tropical rain forests act as a sink for carbon dioxide; when trees are burned the CO 2 is released
back into the atmosphere.
c. CO2 is a greenhouse gas and contributes to global warming; not all life may be able to adjust to the
climate change.
6. Ecotourism
a. In the U.S., 100 million people spend a total of $4 billion a year on fees, travel, lodging, and food in order
to enjoy natural environments.
b. Activities include sport fishing, boating, hiking, bird watching, whale watching, etc.
C. Biodiversity and Natural Ecosystems
1. Massive changes in biodiversity impact ecosystems and the ability to provide the previous values.
2. Research indicates that high diversity improves the efficiency of ecosystems.
a. Minnesota grassland plots with more species had lower inorganic soil nitrogen.
b. California plots with more diversity had greater overall resource usage.
c. Net primary productivity increased as diversity increased at all trophic levels.
d. Computer modeling predicts 30% more photosynthesis with nine different tree species rather than one
single species.
3. Additional research may determine the effects of environmental change, invasion, pathogens, and
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