Mass Extinctions AP Bio Pogil
Species may become extinct for many different reasons. Brainstorm with your group and list five different factors that might cause a large number of species to become extinct
1. Drought 2. Invasive species 3. An Increase in a rival species population 4. Human interference 5. Climate change
Using the graph in Model 2, estimate how long it takes for the number of families to recover after a mass extinction
Between 400 & 20 million years (150 million years average ish)
The letters below each era refer to discrete time periods that are listed in the table below. Complete the columns to indicate the approximate length of time each period lasted. (Part 3)
Cenozoic P: 65.5 N: 23.5
Circle the five major mass extinctions on the graph in Model 1
Circle the 5 largest spikes on Model 1
What is the "Immediate effect" of mass extinctions on the number of families of organisms?
It decreases the number of families dramatically
The number of families of organisms is an indicator of biodiversity. Looking at the graph, what can you conclude about the biodiversity on Earth over the time period shown?
It has increased over time
How is the dependent variable in Model 2different from that in Model 1?
Its the number of Families instead of individuals
How did the extinction of the dinosaurs allow the adaptive radiation of mammals to occur
Mammals had less predators to worry about, allowing them to increase in population.
List the period in which each mass extinction begins and ends
Mass Extinction 1 begins in (Ordovician) and ends in (Silurian) Mass Extinction 2 begins in (Devonian) and ends in (Carboniferous) Mass Extinction 3 begins in (Permian) and ends in (Triassic) Mass Extinction 4 begins in (Triassic) and ends in (Jurassic) Mass Extinction 5 begins in (Cretaceous) and ends in (Paleogene)
The letters below each era refer to discrete time periods that are listed in the table below. Complete the columns to indicate the approximate length of time each period lasted. (Part 2)
Mezoic T: 251 J: 200 C: 145
Predict what wold have happened if all of the early mammals living 66 million years ago had died out in the cretaceous mass extinction
No mammal species would exist today, including humans.
On the graph in Model 2, mark the location of the five mass extinction events depicted in Model 1 with arrows
On Graph 2, draw arrows where the 5 mass extinctions were on model 1. (Use the answers from question 6 for help)
According to Model 1, approximately how long did each of these eras last?
Ordovician, Devonian, Permian, Triassic, Cretaceous
In light of your group's answers to the previous questions, what would you predict to be the long-term result of a sixth mass extinction?
The loss of many animal species and mass climate/ecosystem change
What data could you collect that would support the idea that we are currently at the start of the sixth mass extinction?
The number of species populations now and how it compares to past generations
What evidence do you see from Model 2 that large scales adaptive radiation occurred following the five mass extinctions?
There is always a large recovery in number of families shown in Model 2
To what does the y-axis on the graph in Model 1 refer?
Total Extinction Rate Per Millions of Years
Every mass extinction leads to the rise of prominence of new groups of organisms Using resources from the internet, research what type of organisms were dominant after each of the five mass extinctions
Triassic- Therapsids & Archosaurs Ordovician- trilobites, brachiopods, corals, and more marine life Devonian- conodonts & Trilobites Permian- Therapsids, Archosaurs & Reptiles Cretaceous- Alligators, Crocodiles, Birds, Lizards & Salamanders.
Look at your group's answers to Question 10. Were any of these explanations given in the "Read this!" box also on your list? If not and them now.
Yes, Climate change
What is the overall trend shown in the graph in Model 2
a plateau during the Paleozoic era and a slow climb at the beginning of the mesoic era
The line never reaches zero. What does this tell you?
Extinction has and will always be happening.
The line on the graph is never flat. What does this tell you about the rate of extinctions over time?
Extinctions are always happening, and the rate of extinction never spikes or dips
What is the source of the data collected to produce the graphs used in this activity?
Paleontoloy and ecology records
The letters below each era refer to discrete time periods that are listed in the table below. Complete the columns to indicate the approximate length of time each period lasted. (Part 1)
Paleozoic E: 542 O: 488 S: 444 D: 416 C: 359 P: 299
What are the names of the three eras identified on the x-axis in Model 1?
Paleozoic, Mesozoic, Cenozoic
According to Model 1, approximately how long did each of these eras last?
Paleozoic: 2,799 Million Years Mesozoic: 596 Million Years Cenozoic: 89 Million Years
Many biologists propose that we are currently in a sixth major extinction. If this is true, this mass extinction event may be the first caused by one of the earth's inhabitants, humans. What human action do you think may cause this increased rate of extinction today?
Pollution of ecosystems
What appears to be one criterion that scientists use when defining the timing of geologic periods?
Scientists tend to base periods off of when extinctions occur
Propose an explanation for why small rodents were able to survive the Cretaceous mass extinction.
When other species decreased during the cretaceous extinction, this left room for small rodents to rise and thrive.
