Ch 24: Human Population, Planetary Resources,

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Ch 24 Human Population, Planetary Resources,
Conservation
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Human Population

• Growth rate of a population is determined by
  difference in birthrate and death rate.
• Growth rate peaked at 2 in 1965 current world
  growth rate is 1.3

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Two Types of Countries

• More Developed Countries (MDCs)
• Population growth is modest (overall 0.1)
• Good standard of living
• Less Developed Countries (LDCs)
• Population growth is dramatic
• Majority of people live in poverty

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Growth the Environment

• Biotic potential the maximum growth rate under
  ideal conditions
• Environmental resistance declines growth rate
  because of limiting factors
• Carrying capacity maximum population that the
  environment can support for an indefinite period

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Human Use of Resources Pollution

• Resource anything from the biotic or abiotic
  environment that helps meet the needs of
  survival.
• Two types of resources
• Nonrenewable limited in supply
• Renewable not limited in supply
• Pollution any alteration of the environment in
  an undesirable way

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Limited Resources

• Land human Habitation
• Beaches at least 40 of the worlds population
  lives near the coast and this leads to beach
  erosion and loss of marine habitats.
• Semiarid land human habitation can lead to
  desertification (which is conversion of semiarid
  land to desert like conditions) from allowing
  animals to overgraze the land.
• Tropical Rain Forest human habitation can lead
  to deforestation (removal of trees and then
  habitats for native organisms)

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Limited Resources

• Water - Freshwater is available as surface water
  aquifers.
• Build dams to increase supply but may not be
  useful for long
• Lose water due to seepage into underlying rock
  beds.
• Salt left behind due to evaporation and
  agricultural runoff increase salinity and can
  make the a rivers water unusable further
  downstream
• Hold back less water over time due to sediment
  buildup
• Aquifers people remove water at a rate that
  cannot be sustained and leads to sinkholes and
  saltwater intrusion
• 70 of all freshwater is used to irrigate crops,
  but farmers could use drip irrigation to reduce
  water use by 50

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Limited Resources

• Food
• Farming - supply of food has been increased due
  to modern farming methods, but these methods can
  be harmful
• Planting a few genetic varieties
• Heavy use of fertilizers, pesticides, and
  herbicides
• Generous Irrigation
• Excessive fuel consumption
• Domestic Livestock
• Large portion of farming goes to feed livestock
• For every 1lb of meat, they use 10 lbs of grain
• Injection of growth hormones antibiotics

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Limited Resources

• Energy
• Nonrenewable Sources
• 75 of the worlds energy supply come from fossil
  fuels that will eventually run out
• Fossil fuels produce greenhouse gases that affect
  global warming.
• Renewable Sources
• Hydropower converts falling water into
  electricity
• Geothermal Energy getting hot temperature from
  the earths crusts and converting the heat into
  steam
• Wind Power using a windmill to create energy
• Solar Energy taking energy from the sun,
  storing it, and then converting it to electricity.

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Limited Resources

• Minerals
• Non-metallic Sand, Gravel, Phosphate
• Metallic Aluminum, Copper, Iron, Lead, Gold
• Strip mining An invasive way to obtain
  minerals, which can lead to whole mountaintops
  being destroyed. This leads to ruined habitats
  and wildlife as well as cause toxic waste to be
  deposited in nearby streams and rivers.

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Hazardous Waste

• In addition, to using up our resources, we are
  depleting the available resources by dumping
  hazardous wastes.
• Biological magnification accumulation of
  synthetic organic chemicals that becomes
  concentrated at higher trophic levels.

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Loss of Biodiverstiy

• Biodiversity variety of life on Earth,
  described by the of different species and their
  abundance.
• We are losing our biodiversity, because of
• Habitat Loss
• Alien Species introduction of nonnative species
• Pollution
• Acid Rain
• Global Warming
• Ozone Depletion
• Synthetic organic chemicals
• Overexploitation occurs when a number of
  individuals are taken from the wild
• Disease from exposure to domestic animals and
  their pathogens

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Examples of Species Loss
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Indirect Values of Biodiversity

• Biogeochemical Cycles
• Waste disposal via decomposers
• Provision of fresh water via sponge effect
• Prevention of soil erosion
• Regulation of climate by reducing CO2
• Ecotourism

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Direct Value of Biodiversity

• Medicinal value
• Rosy Periwinkle leukemia Hodgkin
• Armadillo - leprosy
• Horseshoe crabs substance that makes
  pacemakers, implants, prosthetic devices free of
  bacteria
• Agricultural value
• Available wild strains
• Biological pest control
• Consumptive use value
• Fish
• Wild Game
• Fruit Vegetables
• Rubber

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Unsustainable vs. Sustainable Society