BISC 309 Lecture Notes - Lecture 1: Primary Production, Ecological Footprint, Habitat Fragmentation
19 Oct 2015
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Document Summary
Natural ecosystems are being altered by us. Population grown > 70 million per year + increasing/unsustainable resource use > massive ecological footprint. 20-30% of net primary productivity (i. e. energy from sun transformed into plant biomass) Ecological footprint: area required to grow food, support lifestyle, assimilate waste. Require 4 earths to support us consumption. uses 5x energy of average global citizen. Least influence in northern latitudes and deserts. basically where its difficult for humans to live. 5 major categories of human induced threats to biodiversity. as population size and consumption increase human activity are going to increase. How agriculture affects biological diversity= habitat loss, lots of methane, pesticide use, habitat degradation, pollution, land cover change, habitat fragmentation. Background extinctions: the normal disappearance of taxa through time. Major anthropogenic threats: habitat clearance and degradation, overexploitation, invasive species. Loss of species: orders of magnitude higher than background (e. g. tropical forests. 0. 1-0. 3% of species/yr). some areas of earth more diverse and more threatened.
