The Day The Mesozoic Died

Many different pieces of evidence lead to the formation of the asteroid hypothesis and provided support for the hypothesis, including A. Finding tsunami deposits in the Brazos River Basin, Texas. B. Determining that rocks taken from the Chicxulub crater are the same age as the K-T boundary. C. Discovering gravitational field anomalies on the Yucatan peninsula, from surveys done for oil exploration. D. Finding high levels of iridium in the K-T boundary layer. E. Identifying spherules and shocked quartz in Haiti. F. Finding that an isotope of plutonium is not in the K-T boundary layer. G. Observing differences in foraminifera fossils above and below the K-T boundary layer.

USE FOR THE FOLLOWING THREE QUESTIONS!

What did Dr. Carroll mean at the end of the film when he said, "It's not always the survival of the fittest; sometimes it's the survival of the luckiest?"

All dinosaurs were wiped out, but enough mammals were left to repopulate the planet. Mammals were not necessarily more fit, but just happened to occupy niches that allowed them to survive harsh, pot-impact conditions.

Which of the following events are possible sources of high levels of iridium in sediments? Write 'yes' or 'no' next to each of the four possibilities. There may be more than one 'yes' response.

An asteroid impact: Yes Rain: No Fossilized foraminifera: No A supernova: Yes

What was the critical piece of evidence (a-g) that supported the hypothesis that an asteroid had struck Earth 66 million years ago?

B.

Describe the differences scientists saw in the foraminifera found in rock layers above (after) and below (before) the K-T boundary.

Below- Foraminifera fossils were larger and more diverse. Above- Most foraminifera fossils disappeared; surviving species were smaller.

Which fields of study contributed to the research that led to the impact hypothesis? Circle all that apply.

Biology, Geology, Math, Physics, Chemistry

Which piece of evidence (a-g) lead scientists to conclude that the cause of the K-T boundary layer was extraterrestrial in nature?

D.

Which of the following pieces of evidence prompted researchers to abandon the hypothesis that a supernova caused the high levels of iridium in the K-T layer? Select one response.

D. Lack of an isotope of plutonium in the K-T boundary layer.

If the rocks outside of Gubbio, Italy used to be at the bottom of an ocean, how are they now part of a mountain?

Tectonic forces uplifted the land.

What is the K-T boundary?

A thin layer of clay that separates rock layers from the end of the Cretaceous period to those from the beginning of the Tertiary period.

How could an asteroid impact kill off so many different species? Select one response. A. Debris from the impact orbiting around the Earth shields sunlight, halting photosynthesis. B. Tsunamis, landslides, and earthquakes caused by the impact killed organisms near the site of impact. C. The impact was so extreme that life at ground zero was vaporized. D. Both A and C are possible. E. A, B and C are possible.

E. A, B, and C are possible.

Which piece of evidence (a-g) lead scientists to dismiss the supernova hypothesis?

F.

Is the following statement true or false? Justify your answer in one or two sentences: "The entire scientific community accepted the asteroid hypothesis after Dr. Alvarez published his paper showing high iridium levels at the K-T boundary."

False. High level was one piece of evidence, not the definitive piece of evidence. It took other clues like spherules, shocked quartz, and finding the crater for the scientific community to accept the hypothesis.

Explain why the scientific community was slow to accept the asteroid impact hypothesis.

Geologists believed earth changed slowly and gradually without major catastrophes. The hypothesis was also brought up by a physicist, which paleontologists were not into.

Why do we define the K-T event as a mass extinction event? Write 'yes' or 'no' next to each of the five possibilities. There may be more than one 'yes' response.

Many species of foraminifera went extinct: No A large portion of species went extinct: Yes The extinction occurred in many habitats around the world: Yes T-Rex went extinct: No Many life forms near Gubbio, Italy were obliterated: No