Timeline and Layers
About how many years ago did the Cretaceous Paleogene extinction occur?
About 66 million years ago
Name one dinosaur fossil included in the fossil record.
T-Rex or Triceratops
What percentage of all species went extinct during this era?
75 percent
did crocodilians survive the extinction event?
yes
Which law explains why the oldest fossils are found at the bottom layer, also used to determine relative dating (what we used in our project!)
The law of Superposition
Which geologic time period comes directly before the Cretaceous era?
Jurassic era
What is the one index fossil shown in the record?
ammonites
What major group of animals went extinct at the end of tue Cretaceous period?
non avian dinosaurs
Which group survived and became more common afterward?
mammals
In what type of rocks are most fossils preserved because of burials in sediments?
Name one geologic time period included in the fossil record.
Permian, Triassic, Jurassic, Cretaceous, or Tertiary.
Name one reptile that survived the mass extinction?
crocodillians
Name one marine organism group affected by the extinction.
Large marine reptiles, or ammonites
Which species from the fossil record survived while dinosaurs did not?
Crocodilians
What type of fossil is used to define and identify geologic periods based on its wide distribution and short time span?
Index fossil
Which period represents the youngest rock layer in the model
Tertiary
Why is it important to include different types of organisms?
to show biodiversity before and after extinction.
Why is this extinction considered a mass extinction?
because a very large percentage of species went extinct in a short time.
Why might aquatic animals have survived better than land dinosaurs?
better adaptation, or had more stable food sources.
What is the study of fossils and ancient life forms called?
Paleontology
Why must at least one layer be above and below the extinction layer?
To show life before and after the extinction event
What was the main cause of the mass extinction?
a massive asteroid impact in Mexico's Yucatán Peninsula.
What major changer in life on Earth happened after this extinction?
the rise and spread of mammals
What does survival of some species show about extinction events?
not all life dies, some species adapt and survive.
What term describes the layers of sedimentary rocks where fossils are often found?
Strata