Topic 34 Flashcards
Human population
10,000 yrs ago = 5 mill
200 yrs ago = 1 bill
2 yrs ago = 7 bill
Historical shift
8000 yrs ago the dawn of agriculture and animal husbandry. 1760-1840 = industrial revolution.
Humans are like no other spices that has..
modified the ecology and evolution of so many other species
Anthopocene
current geological age in which humans have the largest impact
What are the causes of anthropogenic mass extinction
- habitat loss
- climate change
- introduced species
- over-harvesting
Industrialized agriculture is practiced undeveloped countries to meet the food needs of the population..
- requires large tracts if land for machine to operate effectively,
- crops (wheat, corn) are grown and little organic mayor is left to return to the soil.
- tilling exposed the soil to wind and water erosion resulting in large amounts of top soil loss
60% of the Earth is used for
cropland, forestry and rangeland and many terrestrial biomes cleared for these reasons.
Only 2-3% has been converted to
urban development
Clearcutting in the marine environment is by..
trawling
Increasing average temp of the Earth
2-6 C in next 100 years, will not be felt equally everywhere
Equivalent to warming since the last glaciation only..
50x faster and human induced by increasing burning of fossil fuels (high CO2 in atmosphere)
Will likely cause the world wide ..
extinction of many species
Unintentionally and intentionally humans have acted as a ..
dispersal agent for countless species. some fail to survive while other flourish, freed form constraints in their native systems they establish and spread.
Introduced species are often..
invasive and spread aggressively and displace other species reducing biological diversity in locations in which they establish and are dominant. may cause extinction of vulnerable native species
