Geography 1001 Climate Vegetation Instructor Andr s Holz Teaching Assistant Eungul Lee Agenda for Lecture 13 Thursday June 29 Announcements Yesterday s lecture is online First reading for guest lecture is also online FIELD TRIP TO ISABELLE LAKE INDIAN PEAKS Objective MEET AT THE REC CENTER TURN AROUND AT 9 AM WE WILL DEPART PROMPTLY Agenda for Lecture 13 Thursday June 29 Gear Requirements hiking boots the trail is muddy in places and there is still some snow on the ground raingear sun block chap stick Sunglasses hat gloves warm layers fleece notebook and pen to take notes FIELD TRIP TO ISABELLE LAKE INDIAN PEAKS Access and Trail Description Lake Isabelle is one of the more beautiful trails in the Front Range The lake lies near timberline in a dramatic valley offering views of high peaks such as Shoshone Apache and Navajo Peaks Distance 2 0 miles one way Lake elevation 10 868 feet Trailhead elevation 10 480 feet Net elevation gain 388 feet Agenda for Lecture 13 Thursday June 29 Today s lecture Historical development of the ecosphere Biological processes that changed the atmosphere Anaerobic respiration Photosynthesis Aerobic respiration Atmospheric changes Increase O N Stabilization of CO2 O3 layer Agenda for Lecture 13 Thursday June 29 Today s lecture A bit of ourselves DNA Earth colonization Changes on earth Milankovi Be aware of How the Ecosphere have developed over time Timeline and processes occurring How Climate Life on earth have coevolved The fact that regardless of co evolution we still have large scale climate changes Milankovi Theory A bit of history here 500 million years ago 400 million years ago 300 million years ago 200 million years ago 100 million years ago 50 million years ago 1 million year ago Less than a million year ago So far we know that the Earth has experienced at least 8 ice ages Last one Today If we think of the earth life being a calendar year i e from Jan 1 to Dec 31 when do you think we appeared But how have the conditions for life changed over these 4 billion years The solar system form 4 6 billion years ago 4 billion years ago the atmosphere was made of from volcanic emissions TIME 4 billion yrs ago PROCESS Water vapor Ammonia NH3 Methane CH4 Hydrogen sulfide H2S Hydrogen gas H2 Carbon monoxide CO Very little O2 N2 All water was held in the atmosphere as vapor because of high temperatures water vapor greenhouse effect TIME PROCESS 4 billion yrs ago H2O CO2 N dominant 3 1 3 5 billion yrs ago CO2 H2O N2 dominant O2 begins to accumulate Cooling of the atmosphere causes precipitation and the development of the oceans Break of H2O by ultraviolet rays H2O O2 H Water vapor clouds common in the lower atmosphere First single cell algae bacteria TIME PROCESS 3 1 3 5 billion yrs ago Anaerobic respiration Single cells algae were able to produce Energy without O2 Take C H20 simple organic molecules food break down into CO2 alcohols energy For 800 millions of years CO2 was released as by products of respiration built up in the atmosphere and oceans There was enough CO2 in the atmosphere to sustain life PROCESS TIME Photosynthesis Single cells bluegreen algae have chlorophyll 2 3 billion yrs ago sunlight CO2 H2O CH2O O2 energy Initially the released O2 was lethal to the living organisms food built up TIME 1 9 billion yrs ago PROCESS Ozone O3 layer is being built in the stratosphere Filters out the UV radiation make life possible on land development of O2 tolerant organisms Aerobic life on the land took longer to start because it could only occurred after the ozone layer was formed TIME 1 3 billion yrs ago CH2O O2 PROCESS Aerobic respiration CO2 H2O energy TIME 600 mill yrs ago PROCESS Life is widespread in the oceans Single cells Early fishes Large algae TIME 420 mill yrs ago PROCESS Life is widespread on lands Earliest plants Invertebrates Vertebrates TIME 350 mill yrs ago PROCESS Development of tropical rainforest fossil fuel today s oil TIME 200 mill yrs ago PROCESS Colonization of larger vertebrates A bit of ourselves Date of Separation according to Mitochondrial DNA Early Human Phylogeny Africa Asia Asia Europe eastern Africa Africa southern Africa eastern Africa Europe W Asia Expansion of Human Habitat old theory At 18 000 years ago the Earth looked like this map from Earth and Life Through Time Food Chain of Land Animals World Population Trend from 10 000 B C to 200 A D First civilization collapse Eastern Island Mayas Empire UN World Population Prospects 1992 Why has climate change Meteorite impacts very infrequent random Hugh Volcanic eruptions more frequent but still random Enough evidence of glacial and interglacial periods for the last 2 3 mill yrs Hypotheses Theories Laws the same Milankovi cycles Theory Performed detailed calculations concerning the periodicity of the earth s orbital parameters Precession Axial tilt Eccentricity Eccentricity During periods of high eccentricity higher differences between max min distance from sun to earth more potential for extreme cold warm climate Orbit eccentricity Tilt angle or obliquity Tilt angle or obliquity The greater the angle of the tilt the greater the potential for extremes in seasonal climate especially for polar regions Precession or wobble Precession or wobble It s a slowing down of the rotation of the earth tilt of the earth point to various directions like the axe of a spinning top Evidence of glaciations Swiss hunter in the Alps 1815 associated scratch marks on rocks with the P of ice Yosemite How do scientists track glaciation Stable isotopes from zooplankton tiny shells of calcite Come from seawater Once dead built up on the ocean bottom as layers 2 5 cm or 1 1 000 yrs Comparison between O2 isotope record Milankovi theory How do scientists track glaciation Lighter Oxigen 16O evaporates with water vapor due to insolation and then precipitates as either a rain and returns with rivers and groundwater to oceans seawater remains the same interglacial e g now Or b snow and accumulates and does NOT return to oceans seawater change rate between 16O 18O