Threat to Biodiversity

Biological Diversity (biodiversity)
› Total number of species in the biosphere
› The variety of life on earth
Ecosystem Diversity
› Variety of habitats, communities, & ecological
processes in the living world
Species Diversity
› Number of different species in the biosphere
Genetic Diversity (w/i species)
› Total of all different forms
Global Environment Concerns
Rising tides
Cape Hatteras in North Carolina
More pests
White Spruce trees in Alaska
No snow
Mount Hood in Oregon
•Species diversity refers to the variety of species within
Rainforest are among the most
biodiverse Ecosystem in the World
Malaysia is one of the 12 world hotspots for
Why is biodiversity so important?
We could call it our 'life support system'.
What threatens
Many human activities have a negative effect upon our biodiversity.
Each time we change the natural environment we change the environment
that biodiversity lives in.
Natural Resource
Is a material that
nature provides
which can be used
in production.
Medicinal Value
Prescription drugs
Homeopathic remedies
Consumptive Use Value
Wild fruits & vegetables, trees
 Skins, fibers, beeswax, seaweed
 Freshwater & marine fish
 Natives - hunting
Agricultural Value
Crops came from wild plants
Biogeochemical Cycles
 Waste Disposal
Fresh Water
Water Cycle
Prevention of Soil Erosion
 Regulation of Climate
 Ecotourism
 Natural Beauty (Aesthetic Value)
Regions of the world that contain unusually
large concentrations of species.
 Biodiversity is highest at the tropics.
The most remarkable
places on earth are also
the most threatened
Trans Pecos
Edwards Plateau
Llano Uplift
Human Activity
1. Habitat Loss
 Habitat fragmentation
2. Demand for Wildlife Products
 Poaching
3. Non-native Species
 Invasive species
4. Pollution
 Biological magnification
Habitat Fragmentation
› Splitting of ecosystems into small fragments
Poaching – illegal hunting
 Overexploitation – overharvesting (overuse)
Throughout history there have been species pushed to extinction
› Food
› Ivory
› Clothes
› Décor
› Trade
› Tourists
› Medicine
Tragedy of the Commons
› The idea that any resource that is free &
accessible to everyone may eventually be
destroyed. People may take advantage of a
resource without also taking the responsibility to
maintain it.
› Exploitation (overuse) of resources is due to the fact that
increasingly, humans modify ecosystems as a result of
population growth, technology, and consumption. Human
destruction of habitats through direct harvesting, is threatening
current global stability, and if not addressed, ecosystems will be
irreversibly affected.
Invasive Species – plants & animals that
have migrated to places where they are
not native
› Moved by humans accidentally or on
› Outcompete native species
› Reproduce rapidly
› No natural predators or parasites
Feral Hogs (mammal)
Nutria (aquatic mammal)
Chinese Tallow Tree
Japanese Privet (shrub)
European Starling (bird)
English House Sparrow (bird)
Zebra Mussel (invertebrate)
Snakehead (fish)
Emerald Ash Borer (beetle)
Imported Red Fire Ant
Pollution - Any environmental change that
negatively affects the lives & health of
living things
› Enters the biosphere
through land, air, or water
Solid waste
Nuclear waste
Contaminants that can be traced back to
a specific source, location,
and offender.
› Water: Dumping of industrial
waste, sewage treatment
facilities, illegal dumping
› Air: Stationary equipment,
paper mills, oil refineries,
chemical processing facilities
Contaminants that cannot be traced back
to a specific source, location, and offender.
 Comes from many diffuse sources and often
enters in small amounts but can become
 Hard to manage
› Water: runoff
Discovered as a pesticide in 1930s
 Helped1 billion people stay malaria-free for
30 years
1962: Silent Spring by Rachel Carson
“Carson profiles many facets of DDT, besides it ability to kill disease and agricultural pests. DDT
is persistent in the environment. It seems to affect wildlife and non-target species. It is a contact
toxin to animals, and can possibly accumulate in the food chain, leading to neurological effects.
Carson claims it is a carcinogen, possibly poisoning food. For Carson, alternative pest
management strategies are available and need to be considered.”
1972: DDT banned in most nations
Harmful substance enters environment
 Concentration of
substance increases in
organisms at higher
trophic levels
 Affects the entire
food web
 Top-level carnivores
are at highest risk
Conservation = The planned management
of a natural resource to prevent waste
Preservation = The non-use of a natural
resource to prevent waste
Why would you want conservation/preservation
efforts to focus on protecting entire ecosystems & not
just a single species?
Species of Concern
(Watch List)
A species whose _____________
population size is
declining in a way that places it
in danger of extinction
Endangered Species Act (1973)
› Protection for endangered and threatened plant
and animal species & their habitats
 Effectiveness??? Exemptions are often granted if
 No alternatives to the project
 National or regional significance of project
 Benefits outweigh those of any alternatives
CITES (late 1970s)-prohibits trade and
commerce of threatened and endangered
› By 1998: signed by 144 countries
Texas Horned Lizard
Bald Eagle
Alligator Snapping Turtle
Attwater’s Prairie-Chicken
Disappearance of a species from all or part of its range
Ivory-billed Woodpecker
Texas Species
Threatened Endangered
Texas Horned Lizard *
Interior Least Tern
Carolina Parakeet *
Bald Eagle *
Passenger Pigeon *
Timber Rattlesnake *
Navasota Ladies’ Tresses
Red Wolf *
Wood Stork *
Texas Blind Salamander
Jaguar *
Alligator Snapping Turtle * Attwater’s PrairieChicken
Ivory-billed Woodpecker
60 Minutes: Resurrecting the Extinct
60 Minutes: Can Hunting Endangered Animals Save Them?
1. What is biodiversity?
2. List 1 benefit of biodiversity.
3. What 2 Texas Eco-regions have the highest
biological diversity?
4. What is the main threat to biodiversity?
5. What are 3 other human-caused threats to
6. Give 1 example of a non-native invasive
species found in Matagorda County.
7. Give 1 example of an endangered species
found in Texas.

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