Week 7
Paleoclimate and Extinction
Embedded Files
Just as the cycling of molecules through the rocks, water, air, and life helped living things to gain a foothold on this planet it is also responsible for extinguishing species from it. Movements of molecules such as those containing carbon can cycle and balance through negative feedbacks to keep the planet at a relatively stable temperature or positive feedbacks can destabilize the planet and extinct species. Both warming and cooling events that are rapid can make it very difficult for species to adapt or migrate and sometimes cause extinctions. 99% of all things that have every lived have gone extinct. You and the life around you are the 1% that have survived the turmoil of Earth's history.
Day 1
Day 1
Use the graph above to look at the changes in temperature and CO2 over the last 600,000 years. Notice the large fluctuations in average global temperature and trends in CO2 levels.
Review of the Climate System - flows of energy and matter around the globe.
The collapse of the Carboniferous Rainforests extinct many species and contributed to the thick coal beds we see today in the rocks. Huge die offs, if deposited in an environment that guards from decomposition, can store huge amounts of carbon in the sedimentary layers of Earth.
There have been 5 major mass extinctions in the last 600 million years yet we have more overall species currently.
See assignment in Google Classroom called Extinction - Deep Time Exploration
Use the Earth Viewer to check out time periods that had mass extinctions. Your screen should look like the one below. Turn off cities and grid and turn on Mass Extinctions. Make sure you are in the Paleo Earth tab on the left. Use the charts of Temperature, Oxygen, Carbon Dioxide, and Biodiversity to try and get an idea for why these extinctions might have happened.
Day 2
Day 2
Extinction Game
Each student (a population of organisms) must collect what it needs to live. In reality that would be food, shelter, mineral resources, a mate, and whatever else an organism needs from its habitat to survive. Seven different colored cards are spread around the room. Each student must collect no more than one of each color but must collect all seven colors to survive. Groups of students are assigned a random mutation from the mutation wheel. First students have one minute to collect as a practice. Later the time, which represents changes in seasons and habitat affecting collection of resources, will be chosen from the stable environment spinner. Each round resources remain but students will die off showing the opening of niches in die offs and mass extinctions. Later we will use the unstable environment spinner. Students are rarely able to survive the large swings in time that this spinner produces and extinction happens in a matter of several spins thus showing that large, rapid shifts in the climate have a devastating effect on species because it gives them no time to migrate or adapt.
Mutation Wheel
Selects a random mutation that may or may not be beneficial.
Stable Environment
Very little variability in timing of seasons or movement of environments.
Unstable Environment
Very large variability in timing of seasons or movement of environments.
Extinction events can be caused by positive feedback loops that move environments in one direction changing the climate in a way that adversely affects a large proportion of species. Positive feedbacks can direct the flow of CO2 out of or into the atmosphere and oceans causing catastrophic climate altering effects.
Day 3
Day 3
Watch the videos below for an overview of mass extinctions.
Complete the mass extinction lab in Google Classroom
In large die off events, and over long time periods, dead plant and animal material (predominantly phytoplankton) can sink deep into areas of the ocean that have poor oxygenation or circulation. These anoxic conditions do not allow the material to decompose before it is buried and compacted. Over millions of years, heat and pressure on the buried material will turn it to fossil fuels such as oil, gas, and coal.
Day 4
Day 4
Mud Core
Ice Core
Mud and ice cores allow us to look at layers of sediment in oceans and snow on land. These deposits contain chemical and physical evidence of ancient Earth conditions. They give us information about the conditions that led to mass extinction events and about the living things that died in mass during these events.
The ocean floor is the largest carbon sink on the planet aside from the rock of the planet which stores the most. This occurs because deep ocean environments, like those in trenches and basins, are anoxic (low in oxygen) and delay decomposition until they can be fully buried. This keeps the carbon containing molecules of dead organisms from being cycled back to the oceans through decomposition and transfers them to the rock cycle.
Biomolecules compose all life. They are what life uses carbon for. Each of these molecules is characterized by a backbone of carbon with branches mostly composed of CHNOPS.
Day 5
Day 5
Extinction, and Biomolecules Study Guide
What are the six most abundant elements that compose all living things?
Recognize the four types of biomolecules; proteins, lipids, nucleic acids, and carbohydrates.
Know what all of the largest mass extinctions have in common.
Know the effects of increasing or decreasing the concentration of CO2 in the atmosphere.
Know whether or not we are headed for a 6th mass extinction.
Know what positive and negative feedback cycles do.
Know what once living material needs to be preserved in the rocks.
Know how die offs and extinction benefit survivors.
Review
Quiz
Page updated
Google Sites
Report abuse