Human Activities & their Impacts on the Earth’s Environment 4.2

Humans Early History Began as hunter-gatherers No different from other animals In harmony with environment around them Omnivores—top of the food chain Primary: hunting, fishing, farming, mining, & forestry Depend on natural resources obtained from land or sea.

Domesticating Animals lead to… Control the sources of their own food supply Farm output increased and yielded a food surplus people could master other skills  Secondary: manufacturing goods (changing) came after raw materials (natural resource) were obtained. Tertiary: the need for services grew from the other two. Service sector workers: administration, public services, health care, transport and communications, selling goods, leisure, and tourism

Genetic Engineering & GM Crops Genetic Engineering- process of altering the genetic composition of an organism by modifying its own genes or introducing genes from a different species. Selective breeding vs. genetic engineering Involves transfer between unrelated species Biotechnology- use of living organisms or biological processes for industrial, agricultural, or medical purposes. Genetically Modified Crops-

Genetically Modified Foods PRO (Scientists) CON (Environmentalist) “sowing the seeds of a better future” Saving millions from dying Climate change Pests Lack of food for population growth Second Green Revolution is to tinker with genes “Genetic scientist are altering life itself— artificially modifying genes to produce plants and animals which could never have evolved naturally” Creation of super weeds that have no natural controls Replace existing plants and animals further reduction biodiversity Increase in food output has not increased with GM foods like biotech companies claim GM foods are being used in food-rich countries because it will only be made for money

Extinction Natural All species become extinct Mass Extinction-extinction of many species in a relatively short period of geologic time 3-5 mass extinctions on earth so far -Human activity has ACCELERATED extinctions

Extinction rates are RISING: Projected growth of human population and its growing use of resources per person Human influence on climate change Current & projected rates are much higher in biodiversity hotspots Tropical rainforests, estuaries, tropical coral reefs, and wetlands Eliminating, degrading, fragmenting, & simplifying many biological diverse environments that serve as potential colonization sites for new species.

4 Reasons WHY we should CARE about EXTINCTION World species are a vital part of the earth’s life support system Contribute to economic services Will take double the time (5-10 million years) for natural speciation Ethical responsibility that each wild species has the right to live

Ecological Smoke Alarms Endangered Species Threatened Species So few individual survivors that the species could soon become extinct Sumatran tiger, panda bear, Florida panther http://www.fws.gov/endangere d/ Still has enough individuals to survive in the short term Polar bear http://www.iucnredlist.org/sear ch

Most important, Direct causes of extinction, resulting from human activities: HIPPCO --Habitat Destruction, degradation, & fragmentation --Invasive Species --Population growth & increasing use of resources --Pollution --Climate Change --Overexploitation H I P C O

Habitat Fragmentation Large, intact area of habitat is divided into smaller, isolated patches or “habitat islands.” National parks & reserves

Invasive Species Prevention of Invasive Species: Fund massive research program to identify possible invaders, etc. Increase ground surveys & Satellite observations to track invasive species and develop better models for predicting how they will spread Establish international treaties that ban harmful invader species Require Cargo ships to discharge their ballast water or sterilize water, pump nitrogen into water Educate the public about the effects of releasing exotic plants & animals Cause economic and ecological damage that average at least $162,000 an hour, worldwide Ex: Kudzu Vine (Pro/con?)

Tourism