END-CRETACEOUS MASS EXTINCTION (4/27)

Question 1

Hadrosaur teeth vs. Sauropod teeth

Answer 1

• Hadrosaur teeth vs. Sauropod teeth
○ Sauropod peg-like teeth were used to nip off vegetation and swallow it
○ Hadrosaur washboard-like teeth were used to grind and chew vegetation

Question 2

Coevolution of herbivorous dinosaurs (teeth) and land plants with particular emphasis on the rise of angiosperms

Answer 2

• Coevolution of herbivorous dinosaurs (teeth) and land plants with particular emphasis on the rise of angiosperms
○ Dinosaurs would eat everything in their path, including all the tall conifers. Over time angiosperms would be favored for their shorter reproductive cycle, while conifers would be overwhelmed by all the dinosaurs
○ Angiosperms were the dominant large plants in the cenozoic

Question 3

What are angiosperm land plants? (think about their flowers, reproductive biology, and rapid growth to sexual maturity)

Answer 3

• What are angiosperm land plants? (think about their flowers, reproductive biology, and rapid growth to sexual maturity)
○ Flowering seed plants
○ Embryo develops in the protective ovary of the flower
○ Double fertilization
○ Angiosperms have a reproductive cycle of a few weeks vs gymnosperms 18-month reproductive cycle

Question 4

When do angiosperm land plants first appear in the fossil record?

Answer 4

○ Early Cretaceous

Question 5

What do fossil nest sites and trackways tell us about dinosaur behavior and social structure?

Answer 5

• What do fossil nest sites and trackways tell us about dinosaur behavior and social structure?
○ The young are reared in the nest, similar to warm-blooded endotherms like birds
○ Communal nesting sites suggest seasonal breeding, migration, and birthing

Question 6

When was the “End-Cretaceous Mass Extinction”? from Into the Jungle – “Day the Mesozoic Died” Victims of the End-Cretaceous Mass Extinction (marine and terrestrial biotas)

Answer 6

○ It took 10,000 years for the marine ecosystems to recover from the meteor

Question 7

Walter and Luis Alvarez: Gubbio, Italy

Answer 7

• Walter and Luis Alvarez: Gubbio, Italy
○ Walter - wanted to measure time on the KT (K/Pg) boundary
○ Louis Alvarez - knew to use the iridium to measure time

Question 8

Various lines of evidence for extraterrestrial cause of End-Cretaceous Mass Extinction, what are they?

Answer 8

• Various lines of evidence for extraterrestrial cause of End-Cretaceous Mass Extinction, what are they?
○ Shocked quartz
○ Microspherules (tektites)
○ Iridium anomaly
○ Yucatan Crater (the circle of potholes)

Question 9

Do you think a bolide impact, like that at the End-Cretaceous could happen again in the future?

Answer 9

○ Yes, but maybe not the same extent as the End-Cretaceous meteor