Download 6-1 A Changing Landscape

6-1 A Changing Landscape
Earth as an Island
Human Activities
Among human activities that affect the biosphere are hunting and gathering,
agriculture, industry, and urban development
Hunting and Gathering
agriculture – the practice of farming
monoculture in which large fields are planted with a single variety year after year
green revolution the development of highly productive crop strains and the use of
modern agriculture techniques to increase yields of food crops
Challenges for the Future
Among human activities that affect the biosphere are
 hunting and gathering: mass extinction of animals
 agriculture: planting and growing goods; making medicine; raising animals.
Provides us with a dependable food supply; humans gathered in large
settlements instead of being dispersed.
 Industry: exchange of crops around the world; farmers increased their production
 urban development: Industrial Revolution added machines and factories;
increased the amount of people, waste, necessities
Industrial Growth and Urban Development
6-3 Biodiversity
The Value of Biodiversity
Biodiversity: biological diversity; the sum total of the variety of organisms in the
biosphere
Ecosystem Diversity variety of habitats, living communities, and ecological processes in
the living world
Species Diversity number of different species in the biosphere
Genetic Diversity sum total of all the different forms of genetic information carried by
all organisms living on Earth today
Biodiversity is one of Earth's greatest natural resources. Species of many kinds have
provided us with foods, industrial products, and medicines—including painkillers,
antibiotics, heart drugs, antidepressants, and anticancer drugs
Threats to Biodiversity
Human activity can reduce biodiversity by altering habitats, hunting species to
extinction, introducing toxic compounds into food webs, and introducing foreign
species to new environments
Extinction disappearance of a species from all parts of its geographical range
Endangered Species species whose population size is rapidly declining and will become
extinct if the trend continues
A. Habitat Alteration
Habitat Alteration splitting of ecosystems into small fragments
B. Demand for Wildlife Products
C. Pollution
Biological Magnification increasing concentration of a harmful substance in
organisms at higher trophic levels in a food chain or food web
D. Introduced Species
Invasive Species plants and animals that have migrated to places where they are
not native
Human activity can reduce biodiversity by introducing foreign species to new
environments
Conserving Biodiversity
Conservation wise management of natural resources, including the preservation of
habitats and wildlife
Today, conservation efforts focus on protecting entire ecosystems as well as single
species. Protecting an ecosystem will ensure that the natural habitats and the
interactions of many different species are preserved at the same time.