Transcript Humans in the Biosphere - Emerald Meadow Stables

Humans in the
Biosphere
A Changing Landscape
• * Human activities change the flow of energy in an
ecosystem and can reduce the ability of ecosystems to
recycle nutrients. Some activities that have transformed
the biosphere:
– Hunting and gathering
– Agriculture – domestication of animals, modernization of
practices – Green Revolution (farming practices that increased
yields of rice, wheat, and other crops)
– Industry – machines and factories during 1800s – cities grow
rapidly
– Urban development – spread of suburban communities to new
lands
• All of this activity by humans has affected ecosystems
Renewable and Non-renewable
Resources
• Renewable – can regenerate and are
replaceable, but not necessarily unlimited
• Non-renewable – cannot be replenished by
natural means (fossil fuels – coal, oil, gas,
uranium)
• Sustainable Use – using natural resources at a
rate that does not deplete them
• * Human activities affect the supply and quality
of renewable resources, including resources
such as land, forests, ocean resources, air, and
water.
Renewable Resources
• There are several renewable resources
available:
– Land
– Forest
– Ocean
– Air
– Water
Renewable Resources
(continued)
• Land Resources – soil – should be
renewable if managed properly – plowing
leads to increased rate of soil erosion –
leads to desertification
Renewable Resources
(continued)
• Forest Resources – lumber – should be
renewable – selective cutting vs. clear
cutting – deforestation = erosion
Renewable Resources
(continued)
• Ocean Resources – commercial fishing –
should be renewable – overfishing leads to
stock collapse – Aquaculture (farming of
aquatic ecosystems) an option or limiting
fishing amounts
Renewable Resources
(continued)
• Air Resources – air pollution – smog –
asthma – acid rain, ozone depletion,
global warming – all affect air as a
renewable resource
Renewable Resources
(continued)
• Water Resources – industrial pollution,
domestic pollution, groundwater
contamination
– Need to protect water supply to keep it as a
renewable resource
Biodiversity
• * Biodiversity is the sum total of the
genetically based variety of all organisms
in the biosphere
• Three divisions of biodiversity
– Ecosystem diversity
– Species diversity
– Genetic diversity
Ecosystem Diversity
• Ecosystem Diversity – variety of habitats,
communities, ecological processes
Species Diversity
Insects
54.4%
Protists
4.2%
Other Animals
19.7%
Plants
18%
Fungi
3.4%
Bacteria
0.3%
• Species Diversity
– number of
different species
in biosphere
Genetic Diversity
• Genetic Diversity – sum total of all the
different forms of genetic information
carried by all organisms
Biodiversity
(continued)
• *****Biodiversity is one of Earth’s greatest natural
resources. Biodiversity provides us with foods, industrial
products, and medicines.*****
• * 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 and endangered species (possibly due to overhunting) – can destroy food webs/ecosystems
– Development of land = habitat fragmentation (split ecosystem
into pieces) – less species can live here
– Pollution - DDT – biological magnification – concentrations of a
harmful substance increases in organisms at higher trophic
levels – can destroy food webs/ecosystems
– Introduced species – invasive species – transported/not native –
crowd out native species, often killing native species
Pollution
Magnification of
DDT Concentration
Fish-Eating Birds
10,000,000
Large
Fish
1,000,000
Small Fish 100,000
Zooplankton 10,000
Producers 1000
Water
1
Biodiversity
(continued)
• Conservation efforts focus on protection of
entire ecosystems as well as single
species. This will ensure that the natural
habitats and the interactions are
preserved.
Charting a Course for the Future
• 2 major concerns: Thinning/Depletion of Ozone
and Global Warming
– Ozone Depletion – Ozone absorbs UV radiation –
“hole” in ozone layer = damaging UV radiation. Must
limit CFCs which destroy ozone
– Global Warming – human activities vs. natural
variations in climate (not sure which is the
cause…must study more with models)
• Value of a Healthy Biosphere
- recycle, energy conservation – will help
maintain a healthy biosphere