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Geography 1001: Climate & Vegetation. Instructor: Andr é 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
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Geography 1001:Climate & Vegetation Instructor: Andrés 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
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-wayLake elevation: 10,868 feetTrailhead elevation: 10,480 feetNet 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 • Milanković
Be aware of.. • How the Ecosphere have developed over time: Timeline and processes occurring • How Climate & Life on earth have co-evolved • The fact that regardless of co-evolution, we still have large scale climate changes Milanković Theory
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 4 billion yrs ago 3.1-3.5 billion yrs ago PROCESS H2O, CO2, (N) dominant. 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 3.1-3.5 billion yrs ago PROCESS 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 • Photosynthesis Single-cells (blue-green algae have chlorophyll) • TIME • 2.3 billion yrs ago…. sunlight CO2 + H2O CH2O + O2 built up food • energy • Initially, the released O2 was lethal • to the living organisms
PROCESS • Ozone (O3) layer is being built in the stratosphere • TIME • 1.9 billion yrs ago…. • 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
PROCESS • Aerobic respiration • TIME • 1.3 billion yrs ago…. CH2O + O2 CO2 + H2O • energy
PROCESS • Life is widespread in the oceans • Single cells • Early fishes • Large algae • TIME • 600 mill yrs ago….
PROCESS • Life is widespread on lands • Earliest plants • Invertebrates • Vertebrates • TIME • 420 mill yrs ago….
PROCESS • Development of tropical rainforest • fossil fuel today’s oil • TIME • 350 mill yrs ago….
PROCESS • Colonization of larger vertebrates • TIME • 200 mill yrs ago….
Early Human Phylogeny Asia Africa Asia Europe eastern Africa Africa? southern Africa Europe & W Asia eastern Africa
At 18,000 years ago, the Earth looked like this map from Earth and Life Through Time
First civilization collapse.. • Eastern Island • Mayas Empire
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?
Milanković 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