Pop Growth- Van Forester Human Population Modelo 1975:3.65 billion Underestimated 9%o produced in 1960so one of best models to predict population growtho based on exponential equation factors in death rates (decline due to advance in medicine) Did NOT take into account ZPG movement  China’s one population movement o Prediction usually within 10% of real numbero 2020 estimate = 9 billion people o 2026 population will reach maximum- Pre- Agricultural periodo 100,000 year periodo culture development o pop took 10s of thousands of years to doubleo Pop. = 5-10 million at the end- Agricultural o 10,000 years agoo domestication of plants and animalso doubling time = 1,000 yearso 500+ million at end of the period- Industrial Period- Technology advanceo Fossil fuels- Sanitation/Medicine- Currently at a pop. Of 7 billion Demographic Transition - occurs as countries develop over timeo birth rates stay high while death rates decreaseo Stage 2 mortality transition  People decide to stop having as many kids Death rate and birth rate meet and population levels off  Happens whenever countries rise out of poverty- Latin America Countrieso 46 separate and diverse countrieso See Slide **- European population sizes are decreasingo GDP correlates with birth rateo Birth rate higher in poorer countries (globally) not just in Europe- Wealth = increased sanitation, nutrition, health care- Survivorshipo Number of years a specific group lives (ex:60% survive to age of 25)o Wealth, gender affectso Life Expectancy  US males = 77.7 years, Females = 82.1 Poor Countries close to 50 yearso Age Structure  Looks at survivorship and age specific birth rateo Population momentum  The rate of increase is strongly influenced by people in the pre reproductive class **Population with individuals (see slide The earlier you reproduce will have an impact on your age structure distribution - The rate of increase will be strongly influenced by age offirst reproduction- a population with individuals who produce fewer individuals early in life will actually grow faster than a population w/ individuals who produce more offspring later in life Population growth currently = 1.8% a year- 2050 = 12 billion Optimistic = 1.2%Sustainability vs Carry Capacity- Carry Capacity is the population estimate the earth can support- As population approaches the CC, death rates increase and birth rates decreaseThree E’s of Environmental Issues1. Ecology (study of natures house)2. Economics (mange nature’s house3. Ethics (value nature’s house)- Family Planningo Workso Education decreases birth rate- Some Countries growing too fasto India and Chinao China = one child policy Forced abortion/sterilization  Ecological problems converge with ethical issueso 1996 “one child refugees”o Chinese Orphanages – poor conditions/treatment of toddlerso Preference of Sons over daughters by Chinese parentso What if your only child dies?- Resources being stretchedYellowstone- Preserved for geological purposes not wildlife- 3 million people a year see ol’ faithful - Great losses of trees and species in the Amazono Diversity of people involved trying to help preserve the Amazon - Game reserveso Preserve species for recreational use and large areas of lando Preserves bio diversityo- Large Forests and Grass landso Federal lando Used for mining o Public use- Trying to protect large tracts of land from development - Policieso Est of Protection of Habitato Very little private land in inter mountain west - Utah, Nevada, Wyoming, Idaho Federal land – preserved- England formed Hedgerows to promote biodiversity Large Habitats- Bigger the land areas the more species you can protect- Large animals require very large habitats - Large habitats also support larger population sizeso Keeps genetic diversity up high - The older and Smaller park sizes loses species easier - 43% of mammals since time park was organized were extinct - Mammals are lost if the plot is less than 20,000 sq/km preserved acres - Avg size of national park is 3,000 sq/km“Corridors” like in the Tetons allow population diversity and animal migration- if extinction does occur re-colonization is also made easier - A Single large are is better for reserve than several smallo If you have to use small than the closer they are the bettero A connection or corridor is better than noto- Parks have low plant diversity - Endemismo A species is found in a single location/geographical area and no whereelse on the planet - Gap analysis o Look for gaps in the land sites to preserve species - Largest parks chosen when land is not already being usedo Most in deserts and Mountains Lowest diversity but least used Not preserving species - 6% of the world maintained for biological and animal diversity Restoration - Fresh kills landfill Staten Island, NY- Restored it and turned it into a park- Legislation requires rehabilitation of mine sites and wetlandsBio Remediation- Use natural organisms to detoxify the wastes in the soil and water in an area- Don’t want to create anymore harm while restoring - Find a cause of the degradation - Find a method to remove toxins - Monitor system long enough to determine if the ecosystem has recovered - Attempt to mimic ecological process already