Scientists hypothesize that approximately 250 million years ago, during the Permian period, the world's oceans became depleted of oxygen. A chain of events then led to the Permian mass extinction, a time during which most living species became extinct.
View the NOVA video and answer the questions
- How many years ago did the Permian mass extinction occur?
- What % of species became extinct in the Permian mass extinction?
- Mammal like reptiles and exotic ocean animals were present during the Permian period. What types of life were NOT on Earth 250 million years ago?
- How many major extinctions have occurred on Earth?
- What type of gas did the volcanoes in the Siberian Traps release?
- Water can hold a type of gas critical to living organisms (fish and other aquatic animals require it to survive). What is this gas?
- What type of gas do deadly bacteria in the lower layers of some lakes produce?
- What does this gas smell like?
- Develop a flowchart of the events that led to the Permian extinction
a. Anaerobic bacteria thrive in the oceans and produce hydrogen sulfide
b. Atmospheric carbon dioxide levels increase
c. Atmosphere warms
d. Dissolved oxygen levels in the oceans drop
e. Hydrogen sulfide accumulates in the oceans and atmosphere
f. Most aquatic life that depends on oxygen dies
g. 95 percent of Earth's life is killed by hydrogen sulfide
h. Oceans warm
i. Volcanoes erupt
Explain (briefly) how volcanic eruptions can change the atmospheric and ocean environments.
Atmospheric gases, such as oxygen and carbon dioxide, are soluble in water. How much of a particular gas dissolves in water depends on the temperature of the water and on the pressure of that gas above the water.
The gas in carbonated water (seltzer) is carbon dioxide. The high pressure inside the bottle causes more carbon dioxide to dissolve in the water than would dissolve at typical ground-level atmospheric pressures.
Carbonated water at room temperature
Carbonated water at 4oC
3 glass beakers
40oC water bath
State the hypothesis prior to beginning the experiment. The hypothesis indicates at which temperatures you believe CO2 gas will be more or less soluble in water.
Read through the entire procedure before beginning the experiment
- Obtain 3 - 250 ml beakers. Place one beaker on a bed of ice.
- Pour 100 ml of ice-cold carbonated water into the beaker on ice.
- Pour 100 ml room temperature carbonated water into the other 2 beakers.
- Immediately place a beaker in the 40oC water bath. Bring the beaker on ice and the beaker at room temperature with you so that you can observe them simultaneously.
- Record observations in the data table.
- After 5 minutes, determine the temperature of each water environment by placing the thermometer in the carbonated water.
Analysis and Conclusion
Refer to sections 3.1 and 3.2
- The aspect that varies between groups in the experiment is called the experimental (independent) variable. Identify the experimental variable in the experiment.
- Controlled variables are extraneous factors that are kept constant to minimize their effect on the outcome of the experiment. Identify 3 controlled variables
- The control group provides the baseline to which the experimental groups will be compared. Identify the control treatment in the experiment.
- The dependent variable changes with respect to the experimental (independent) variable. The dependent variable is what is measured in the experiment. Identify the dependent variable.