Ecology week 3Ecology week 3Human Impact on the EnvironmentHuman Impact on the Environment

Humans in the BiosphereHumans in the Biosphere

Like all organisms, we humans Like all organisms, we humans participate in food webs and participate in food webs and chemical cycles.chemical cycles.

Among human activities that affect Among human activities that affect the biosphere are hunting and the biosphere are hunting and gathering, agriculture, industry, and gathering, agriculture, industry, and urban development.urban development.

By the end of the last ice-age – about By the end of the last ice-age – about 11,000 years ago – humans began 11,000 years ago – humans began the practice of farming, or the practice of farming, or agricultureagriculture

Monoculture, fertilizers, and the Monoculture, fertilizers, and the green revolution.green revolution.

Humans in the BiosphereHumans in the Biosphere

Industrial growth and urban Industrial growth and urban developmentdevelopment

Human society and its impact on the Human society and its impact on the biosphere (Earth) were transformed biosphere (Earth) were transformed by the industrial revolution (1800’s)by the industrial revolution (1800’s)

Dense human communities produce Dense human communities produce waste that must be disposed of.waste that must be disposed of.

Certain industrial processes pollute Certain industrial processes pollute air water and soil.air water and soil.

Renewable and Nonrenewable Renewable and Nonrenewable resourcesresources

Environmental goods and services may be Environmental goods and services may be classified as either renewable or nonrenewableclassified as either renewable or nonrenewable

Renewable resourcesRenewable resources: can regenerate if they : can regenerate if they are alive or can be replenished by biological are alive or can be replenished by biological cycles if they are non-living (abiotic), but they are cycles if they are non-living (abiotic), but they are not necessarily unlimited. not necessarily unlimited.

“ “ex: freshwater”ex: freshwater” Human activities can affect the quality and supply Human activities can affect the quality and supply

of renewable resources such as land, forests, of renewable resources such as land, forests, fisheries, air, and fresh water.fisheries, air, and fresh water.

Soil erosion?Soil erosion? Desertification?Desertification?

Nonrenewable resourcesNonrenewable resources: are : are those that cannot be replenished by those that cannot be replenished by natural processesnatural processes• Fossil fuelFossil fuel• CoalCoal• OilOil• Natural gasNatural gas• Nuclear energy???Nuclear energy???

Renewable and Nonrenewable Renewable and Nonrenewable resourcesresources

DeforestationDeforestation Overfishing (aquaculture)Overfishing (aquaculture) Air resources (smog, pollutant, acid Air resources (smog, pollutant, acid

rain)rain) Freshwater resourcesFreshwater resources

Renewable and Nonrenewable Renewable and Nonrenewable resourcesresources

Effects of Acid RainEffects of Acid Rain

BiodiversityBiodiversity

Biodiversity is the sum total of the Biodiversity is the sum total of the genetically based variety of all organisms genetically based variety of all organisms in the biospherein the biosphere

Biodiversity is one of Earth’s greatest Biodiversity is one of Earth’s greatest natural resources. Species of many kinds natural resources. Species of many kinds have provided us with foods, industrial have provided us with foods, industrial products, and medicines – including products, and medicines – including painkillers, antibiotics, heart drugs, painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugsantidepressants, and anticancer drugs

Rosy Periwinkle Rosy Periwinkle ((used to treat certain cancersused to treat certain cancers))

BiodiversityBiodiversity

Human activities can reduce Human activities can reduce biodiversity by altering habitats, biodiversity by altering habitats, hunting species to extinction, hunting species to extinction, introducing toxic compounds into introducing toxic compounds into food webs, and introducing foreign food webs, and introducing foreign species to new environmentsspecies to new environments

Demand for wildlife products???Demand for wildlife products???

PollutionPollution

DDTDDT Biological magnification???Biological magnification??? Chloroflorocarbons (CFC’s) & the Chloroflorocarbons (CFC’s) & the

ozone layer.ozone layer.• UV ~ skin cancer, phytoplankton?UV ~ skin cancer, phytoplankton?

Ozone Layer (OOzone Layer (O33))

Many scientists are concerned about Many scientists are concerned about the thinning of the OZONE layer. the thinning of the OZONE layer.

How Populations GrowHow Populations Grow

Exponential growthExponential growth• BacteriaBacteria• HumansHumans

Logistic growthLogistic growth• Carrying capacityCarrying capacity

Predator / Prey relationshipsPredator / Prey relationships Human populationHuman population

Human Human PopulationPopulation

IssuesIssues

The endThe end