Study Guide: Exam 2 Ch. 17

Question 1

(a) Why were dragonflies (and other flying insects) so much larger 300 million years ago? The answer is in
Figure 17.7 of your textbook, and Figure 17.8 shows an experiments that shows how it is possible.

Answer 1

The accumulation of O2 and the levels in the air.

Question 2

(b) The evolution of which organism caused Oxygen levels to increase? The answer is in the same section as
Figure 17.7.

Answer 2

Ancestors of cyanobacteria

Question 3

(a) How are sedimentary rocks formed?

Answer 3

They are formed by accumulation of sediments.

Question 4

(b) In an areas where sedimentary rocks have been formed, the (choose: oldest/newest) strata is at the bottom.

Answer 4

Oldest

Question 5

(c) Why are sedimentary rocks not good for radiometric dating? Which types of rocks are good for radiometric dating?

Answer 5

Sedimentary rocks are not reliable for radiometric dating because they do not trap the parent and daughter isotopes. Igneous rocks do.

Question 6

(a) Organize these geological into their respective eras (Cenozoic, Mesozoic, Paleozoic), and within the Eras,
organize them from most ancient to the most recent. The answer is in Table 17.1 of your textbook. You
can also use Figure 1 in this guide.
i. Devonian
ii. Cambrian
iii. Jurassic
iv. Silurian
v. Ordovician
vi. Cretaceous
vii. Quaternary
viii. Paleogene
ix. Triassic
x. Permian
xi. Carboniferous
xii. Cambrian

Answer 6

Paleozoic
- Cambrian
- Ordovician
- Silurian
- Devonian
- Carboniferous
- Permian

Mesozoic
- Triassic
- Jurassic
- Cretaceous

Cenozoic
- Tertiary
- quaternary

Question 7

(a) What type of evidence do scientists have to support the idea that a giant meteorite hit the Earth at the
end of the Cretaceous period? See Figure 17.5.

Answer 7

iridium between a layer of two rocks

Question 8

(b) How long ago did the meteorite hit? The answer is in the same section.

Answer 8

66.5 million years ago

Question 9

(a) What is the difference between fauna, flora, and biota?

Answer 9

biota - an assemblage of all kinds of organisms living in a particular place or time period.

fauna - the animals

flora - the plants

Question 10

(a) What is an amniote?

Answer 10

vertebrates with well-protected eggs that can be laid in dry places.

Question 11

(b) Are amniotes vertebrates?

Answer 11

Yes

Question 12

(c) Are humans amniotes? (Hint: think of “water breaking” during childbirth, as we discussed in class)

Answer 12

Yes