SWES 210 Test 2Human Population and Growth- Population increases ~8 million people per year- At some point we should reach carrying capacity, but our technology and medical advances keep pushing it highero UN s predicting it could level off at 9 billiono Others think it will collapse and drop down to below 1 billion- Most people on earth live along the coastal regions- Current 1.2% of population growth will result in 14 billion people in 58 yearso For every 1000 people, we will have 1012 people at the end of the yearo (7/1.2=58)- Population growth rate is declining since 1960’s (whenit peaked), but total population is largest nowo Least developed countries peaked in 1990’s- Age distribution and growtho Wide base = many young people  highreproduction rate, rapid growtho Even = births ~ deaths, stable o Inverted = decreasing population- Total fertility rate – average number of children born toeach femaleo Replacement fertility – keeps size of a population stableo What reduces TFR Medical care that reduces infantmortality Childcare in cities is more costly Social security  don’t need too manychildren to support elderly Educated women- Immigration and emigrationo Push factorso Attracting factors- Demographic transition model – preindustrial,transitional, industrial, post-industrial- Thomas Malthus – saw that poor families had more childreno An Essay on Principles of Population – collapse of population, no food, war, etc.- Paul Ehrlich – population bomb 1968o By end of 20th century, civilization would end, but food production increased- Alternatives for 21st Centuryo Conventional world – more poison in atmosphere or policy reformo Barbarization – fortress world (haves and have not’s, rich live in fortresses), breakdowns, authoritariano Great transition – live in harmony with nature and peopleSoil Erosion- Dr. Garcia- When vegetation is taken away from land, nutrients flow into rivers/streams and cause eutrophicationo Once it reaches the ocean it creates dead zones and brings back for the land, creating sand dunes- Over exploiting land the size of Indiana each year due to erosion- Historical Actso 1972 Clean Water Acts – illegal to pollute watero 1998 Storm Water Management Municipal terrain Private land - Current problems – who/how to control erosion- Erosion Control Practiceso Damso Terraces – leveling off parts of the land so runoff doesn’t occur, results in moisture retention of soil on steep slopeso Erosion rolls – so water velocity decreaseso Silt fences – controls and traps sediments for constructional and fire Can’t overflow in order to worko Hydro seeding – 100% effective, mix of mulching, seeds and glue, shoot it on a steep slope and let it growo Branch packageso Post fire erosion controlo Wind control – use high trees to break wind velocity and protect smaller plantso Plant tree on slopes behind trenches to collect water- Agricultural systemso Traditional – powered by people and animals Small scale – low input, low yield Polyculture – more than two types of cropso Industrialized – large machinery, widespread since 1940s Pesticides, fertilizers, GMOs Monoculture Large scale – high input  high yield- Soil: upper 1-2 meters in crusto Mineral particles, organic matter, air, water Bacteria, fungi, algae Decaying organic material Earthworms, insects, mammals, reptiles, amphibianso Layers O horizon – organic litter Topsoil (A horizon) – inorganic material most nutritivefor plants E – eluviated (leaching layer) B – subsoil C – weathered parent material  R – rock (parent material)o Formation Weathering of rocks and minerals and accumulationand transformation of organic matter Five factors: climate, organisms, topography, parent material, time Rates - ~1 cm forms over 500 years Weathering – physical and chemicalo Land degradation – caused by unsustainable agricultural practices Soil erosion (size of Indiana lost per year)- By water- Of Midwest – lost half of topsoil  now in Mississippi river deltao Small patches of original prairie still exist in some states Prevention- Slowing wind and water flowo Roots hold soil in placeo No till agriculture leaves plant residue on fieldso Cover crops to protect soil between plantings- Dust Bowl in 1930’s in Great Plainso People were doing lots of agricultureo Drought and wind erosion caused black blizzards- Protecting soil o Crop rotation – different crops from year to yearo Contour farmingo Terracingo Intercropping – planting different cropso Shelter beltso Conservation tillage/no tillage – increases organic matter and soil biota, prevents carbon from being released into atmosphere, may increase herbicide and fertilizer usageConservation Biology and Wildlife- Rangeland, wildlife, fisheries conservationo No harvesto Recovery of endangered specieso Habitat restorationo Effects of human activitieso Effects of non-native species- Scaleo Large scale foci Structure (what’s there) and function (role)- Ecosystems, landscapes, watershedo Smaller scale foci Species, populations (dependent on habitat), habitat is critical- Conservation biology – study of phenomena that affect maintenance, loss, and restoration of biologic diversity (variety of life) o Aim is to protect species, natural processes and ecosystemso Synthetic draws from biology, ecology, economy, policyo Discipline with deadline – longer we wait to meet objective, the less likely we will be able to save a species because of declineo Diversity – genetic, species, ecosystem (structural)o Crisis discipline – extinction and speciation are natural processes, but human activities have increased the rate of extinction Current rate – 100-1000x higher than normal Causes- Habitat destruction and fragmentation (deforestation, city building, etc.) – when change occurs, some thrive and others can’t- Introduction of non-native species – native species aren’t adapted to exist with non-native ones- Increasing human population – using resources Regional conservation planning – must decide: what/where/how to protect (it)- Financial resources are limited so must make priorities- Establish protected areasGreen Revolution- CGIAR: consultative group on international agriculture researcho Strategic objectives Reduce poverty and hunger Improve health and nutrition Enhance ecosystem resilience through