Envi Sci 1.1

• Early Humans: hunters/gatherers - affected the environment as they burned

prairies to flush prey, and spread plant species through defecation…it is a theory

that over-hunting of some species (plus rapid climate change!) led to extinctions of giant bison, mastodon,

saber-tooth tiger…

• Agricultural Revolution (Neolithic )

- Settlements: early humans stop “wandering” in search of food. Less physical stress, safer.

- Specialization: in settlements, jobs such as weapon & tool making, shelter-building, clothing, medicine(sic), etc. - go to those who perform them best.

• Technology: primitive tools such as hand axes, bone needles, grinding stones, & fishing nets increase efficiency.

• Agricultural Revolution - increased population: steady food supply

(farm land supports more humans than hunting, per acre) through agriculture leads to population growth…which results in a CONCENTRATION of human environmental pressure on local areas.

• Agricultural Revolution - Slash & burn: quick way to convert forest and

wetland into farmland (nutrients from burned trees fertilize the soil), but it causes habitat destruction for all the organisms that used to live there, and eventually results in soil wastage as the nutrients get used up in crops, and erosion.

…it is still used today in less-developed countries.

• Agricultural Revolution - Domestication of plants/animals: all modern-

day food products were once “wild”- humans have tamed & shaped nature to better suit human needs.

Industrial Revolution • (Envi Sci is concerned with the problems

caused by the Industrial Rev...)• (‘thanks” to modern science for making it all

possible...)

Industrial Revolution

energy shift: humans stop using animal muscle & running water to do work – begin using fossil fuel.

(coal...oil...gas...)

in agriculture: it takes fewer workers and uses less land; but increased food yield results

in manufacturing: more product, lower cost

in transportation: able to move goods greater distances/more markets

Industrial Revolution: Pro’s…

PRO• Increased QOL: quality of everyday life got better;

“creature comforts” in all areas• Increased opportunity: education… a trade…• Decreased starvation• Better medical care• Better sanitation

Industrial Revolution: & Con’s…

CON• Urbanization: farmers move to town for factory jobs.• Pollution: undesired change in air, water or soil that adversely affects health

& survival of humans & other orgs.• Exploitation (people & nature): deprivation of basic dignity.• Habitat destruction: cities, roads, suburbs crowd out existing orgs.• Synthetic materials: man-made fertilizer, plastic, pesticides, etc – not

naturally occuring.• Human Population Growth: the more humans there are, the more natural

resources they need – environment is stressed.

The Big Three (Main Environmental Problems)

• Resource Depletion– Renewable: solar, water & wind power; fresh air,

fresh water, trees, crops, soil– Nonrenewable: fossil fuel, minerals

• Pollution– undesired change in air/water/soil which adversely

affects health, survival & activities of humans and/or other orgs

• Loss of Biodiversity– Decrease in the variety and population # of wild

species in a given area

Thanks for your kind attentio.