Ch 4 Review Flashcards
What are examples of human activities?
- agriculture
- logging
- Fisheries
-industry and fossil fuel use - urbanization and road construction
- international trade
What are major threats to biodiversity?
- major threats to biodiversity are a result of human activities.
- habitat loss
-habitat fragmentation - habitat degradation
- climate change
- invasive species disease
- overexploitation
What are examples of loss of biodiversity?
-extinction of species and populations
- degradation of ecosystems
- erosion of genetic diversity and evolutionary potential.
- loss of ecosystem services
- erosion of support systems for human societies.
What are the three ways that humans dominate the global ecosystem?
- Land surface
- Nitrogen cycle
- Atmospheric Carbon cycle
What is land surface?
Human land use, mainly for agriculture and our need for resources, especially from forestry, have transformed as much as half of the earth’s ice free land surface.
What is nitrogen cycle?
Each year human activities, such as cultivating nitrogen fixing crops, using nitrogen fertilizers, and burning fossil fuels, release more nitrogen into terrestrial systems than do natural biological and physical processes.
What is atmospheric carbon cycle?
By the middle of this century,
Human use of fossil fuels and cutting down of forests will result in doubling of the level of carbon dioxide in the earth’s atmosphere.
Root of major threats to biodiversity!
Expanding human population!
- the greatest destruction of biological communities has occurred over the last 150 years.
- during their time, human population has increased from 1 billion in 1850 to 7 billion now.
How much of population is in U.S?
5% of world’s population.
How much resources does U.S use?
About 25% of global resources.
How much paper does average U.S citizen use?
Average U.S citizen uses 23 times more energy and 79 times more paper products than average Indian citizen.
Impact of human population can be measured in equation?
I = P x A x T
P = number of people
A = average income
T = level of technology
What is globalization?
Interconnectedness of resources and labor markets.
What is ecological footprint?
Influence a group of people has on both surrounding environment and location around globe.
What is main threat to biodiversity?
Habitat destruction.
- in U.S, only 42% vegetation remains.
- certain biological communities have declined by 98% or more.
Habitat destruction in tropical rain forest?
-7% of earth’s land
- 50% of earth’s species
-1/3 being destroyed
- remaining is being lost at 1% per year.
Habitat loss and degradation are greatest threats, followed by:
Overexploitation
Intrinsic factors
Tropical forest are cut down due to:
Shifting cultivations of slash and burn
Oil Palm plantations
Habitat Destruction
During the 80’s, Costar Rica and other Latin American countries had some of the world’s high rates of deforestation.
Hamburger connection
Conversion of rain forests in cattle ranches.
Habitat Destruction in Tropical Deciduous Forest
- easier than rain forest to clean and burn
-human population density 5x greater than rain forest - pacific coast of Central America has less than 2% of its original forest
-less than 3% remains in Madagascar home of lemurs.
