U1 lesson 1
How are causation and correlation related?
Correlation without causation is a coincidence.
The mass extinction of the dinosaurs occurred 66 million years ago. This date corresponds to a thin layer in the fossil record with unusually high iridium levels. What did scientists need to do to confirm their hypotheses linking the high iridium levels to the dinosaur extinction?
Find possible reasons for the high iridium levels that also explain the dinosaur extinction.
The unexplained high amount of Iridium in the clay layer found by the Alvarez' is called the
Iridium anomaly
The volcanism hypothesis explains that iridium came from inside Earth. It says that large amounts of lava were erupted where India is located today. What piece of data caused scientists to believe this hypothesis was incorrect?
It was found that the lava did not come from inside Earth.
What is the fossil record?
The history of life on Earth as recorded in fossils.
Why does the moon appear to have more impact craters than Earth?
The moon has no atmosphere to burn up meteors before impact.
How do scientists identify a mass extinction event in the fossil record?
They look for large drop in the number of genera over a short period of time.
The size of the impact crater depends on the __________ and the ________ of the meteor.
mass and speed
Episodes when large numbers of of species become extinct
mass extinction
What are the factors that affect the size of an impact crater?
speed and mass
The Supernova Hypothesis, Volcanism Hypothesis, and Asteroid Hypothesis all were developed to try to explain
the mass extinction of the dinosaurs
