Chapter 6 Practice Test
Major Concept #1: Organisms change across time
1.
Take a look at the horses (ancestors) in the diagram (page 2). You will see a clearly labeled
drawing to show where you would expect to find each of the horse ancestors if you were looking
for fossil evidence in rock layers. One ancestor has been “removed.” Called Merychippus, what
would you expect it to look like? KEEP THE WORDING OF THIS MAJOR CONCEPT IN
MIND AS YOU GIVE YOUR ANSWER!!!!!!! Explain WHY you think it would look like this.
Major Concept #2: Natural Selection explains how species change across time
2.
3.
4.
Describe a selective pressure that might have caused Equus to evolve from these ancestors and
explain HOW it would have led to Equus.
Four of the 5 types of horses in the diagram have gone extinct. Explain, in general terms, what
might have caused the horses, prior to Equus, to have gone extinct. Imagine yourself traveling in
a time machine back millions of years ago and try to come up with some examples of what you
would have seen that led to their extinction.
Describe how the process of natural selection leads to the diversity of species. Whales and
dolphins are both air-breathing, warm-blooded mammals that now live in the sea but they both had
ONE common ancestor that lived on the land. Answer this question using whales/dolphins as the
example. Use the following words in your answer; adaptation, population, natural selection,
selective pressure, variation and species.
Major Concept #3: Multiple lines of evidence confirm evolution
5.
6.
List the (kinds of?) evidence you would expect to find that supports the theory that Equus evolved
from Eohippus. Be specific.
In your opinion, which “line” of evidence is most convincing TO YOU? Give reasons WHY you
chose the line you did. (Imagine you needed to “defend” the theory of evolution to someone that
doesn’t “believe in evolution.”)
Major Concept #4: Earth’s physical environment changes over time
7.
8.
Wooly mammoth (giant hairy elephants) fossils have been found in places as different as Alaska
and Kansas. Explain which state, you think, had the most recent fossils. Which fossil set had the
highest percentage of Carbon-14 the “parent element”? Explain your reasoning. If the fossils in
Kansas had nearly 94% of their parent element, Carbon-14, decayed into the daughter element,
how old would you estimate the fossils to be? Show your work.
Some of the earliest human-like fossils are found in the Rift Valley of eastern Africa. If you
traveled there today you would see a desolate area that would be very difficult for anyone to
survive as there is very little plant or animal life in the valley. How come early human-like
animals were able to survive there?
Radiometric Dating Question
9.
How old would you expect the Merychippus fossils (in the ARIKAREE layer) to be? If the
(OGALLALA) Pliohippus fossils are appx 12,000 years old and the (JOHN DAY) Mesohippus
fossils are appx 18,000 years old, give both the relative and absolute dates of Merychippus
fossils…use C-14 and give its appx decay percentage that would match the relative age.
In each answer you gave, ask yourself, “does my answer ADDRESS THE MAJOR CONCEPT?”