Ch. 20- Human Impact on the Enviroment

First watched one movie.
Key points:
Ecological succession
the process of biological community change resulting from disturbance; transition in the species composition of a biological community, often following a flood, fire, or volcano eruption.
There are two forms of ecological succession: primary and secondary
primary succession- community arises in a virtually lifeless area with no soil
secondary succession- occurs where a disturbance has destroyed an existing community but left the soil intact
Ex. of primary succession: glaciers, starting clean slate
Ex. of secondary succession: fire, landslides, farming
There are three steps in primary succession: 1. lightens 2. colonize 3. mature forest
Solid rock supports life because primary succession starts on rocks. Soon soil formation break the rock's edges and then early colonizers like fungi and low levels of nitrogen grow creating a mature forest. A mature forest consists of a diversity of tree species, slow growing, as well as more nutrients.
Basically creation of barren land is succession.

Picture: http://www.google.com/imgres?q=ecological+succession&um=1&hl=en&sa=N&biw=1280&bih=600&tbm=isch&tbnid=OaPJSybzX76IpM:&imgrefurl=http://berdengbabaesaabudhabi.blogspot.com/&docid=-1Mm7cQ136LHKM&w=480&h=332&ei=gQxwTtjOIsqmsALBuNi4CQ&zoom=1&iact=hc&vpx=296&vpy=299&dur=251&hovh=187&hovw=270&tx=135&ty=101&page=1&tbnh=113&tbnw=165&start=0&ndsp=19&ved=1t:429,r:8,s:0

Notes:
Humans have greatest impact on the communities worldwide. Examples include logging, cleaning for housing, farming, reduction of species diversity

picture:http://www.google.com/imgres?q=logging&um=1&hl=en&biw=1280&bih=600&tbm=isch&tbnid=1Hr-7nAVQw0YjM:&imgrefurl=http://6452ck.edublogs.org/2008/06/02/logging-pictures/&docid=vA2gUiZbTyR0IM&w=500&h=328&ei=8gxwTqC_HeGosAKN1LXnCQ&zoom=1&iact=hc&vpx=156&vpy=180&dur=172&hovh=182&hovw=277&tx=145&ty=73&page=1&tbnh=112&tbnw=149&start=0&ndsp=21&ved=1t:429,r:0,s:0

Environmental problems:
Introduced species: humans accidentally or intentionally move species which they prey on native organisms and out compete native species.
e.x. zebra mussels, fungus, European starlings..
Eutrophication: over fertilization of lakes because sewage outflow, agricultural fertilizers, and pesticides which create heavy algal and bacteria which can suffocate aerobic life including fish.
Deforestation: amount of nutrients leaving an intact forest ecosystem is controlled by plants: no trees=loss of nutrients
Toxic chemical: Store up in fat and magnify up the food chain which creates biological magnification
e.x. DDT, PCB, mercury
Global Warming- marked increase in atmospheric CO2 concentrations because of burning of fossil fuels and wood/deforestation
warming of 2 degrees C=melting of polar ice caps, raise sea level, coastal cities would be underwater, alter precipitation affecting agriculture
Ozone Layer Depletion- Use of chlorofluorocarbons(refrigeration and aerosol cans)
ozone layer protects us from IV radiation which could increase incidence of skin cancer, cataracts, damage crops, and phytoplankton.
ozone layer over Antarctica
Biodiversity Crisis: decline of Earth's diversity in ecosystems
losing species
3 main reasons:
habitat destruction(land, wetland)
introduced species-eliminate native species(starlings and pigeons replaced native birds)
Overpopulation-too much harvest or hunting(whales, rhino, marine turtles)

pictures: http://www.google.com/imgres?q=deforestation+in+india&um=1&hl=en&biw=1280&bih=600&tbm=isch&tbnid=a_vtWVtyFs_KHM:&imgrefurl=http://wn.com/deforestation%3Fupload_time%3Dall_time%26orderby%3DviewCount&docid=X2qrBhQkVAu1QM&w=468&h=312&ei=VxFwToauNsfK0AHs5NziCQ&zoom=1&iact=hc&vpx=499&vpy=303&dur=1578&hovh=183&hovw=275&tx=115&ty=122&page=1&tbnh=109&tbnw=157&start=0&ndsp=20&ved=1t:429,r:9,s:0

http://www.google.com/imgres?q=global+warming&num=10&um=1&hl=en&biw=1280&bih=600&tbm=isch&tbnid=LOXaBo-lscTJgM:&imgrefurl=http://www.spiritofmaat.com/announce/ann_dryice.htm&docid=A8TLSdyqVl5DeM&w=500&h=330&ei=eBFwTp3RDvCNsAK00t3xCQ&zoom=1&iact=hc&vpx=724&vpy=179&dur=1563&hovh=182&hovw=276&tx=181&ty=113&sqi=2&page=1&tbnh=109&tbnw=148&start=0&ndsp=22&ved=1t:429,r:4,s:0

http://www.google.com/imgres?q=ozone+layer+depletion&num=10&um=1&hl=en&biw=1280&bih=600&tbm=isch&tbnid=Jcf6inn5WEv__M:&imgrefurl=http://js082.k12.sd.us/My_Classes/Physical_Science/Phys_Sci_ch_7/ozone_layer_depletion.htm&docid=kN2ABKWnRD_wQM&w=288&h=289&ei=wBFwToWlLeSksQKnvvDcCQ&zoom=1&iact=hc&vpx=619&vpy=160&dur=3211&hovh=225&hovw=224&tx=86&ty=120&sqi=2&page=1&tbnh=114&tbnw=133&start=0&ndsp=21&ved=1t:429,r:3,s:0

Next..sean