SCIENCE REASONING TEST

35 Minutes-40 Questions

DIRECTIONS: There are seven passages in the following section. Each passage is followed by several questions. After reading a passage, choose the best answer to each question and blacken the corresponding oval on your answer document. You may refer to the passages as often as necessary.

You are NOT permitted to use a calculator on this test.

Passage I

A study was conducted regarding the fossil shells of a par­ticular species of turt1e that lives off the coast of the Opula.<;ian Peninsula. Scientists discovered a continuous record of fossil­ized shells in the seabed off the coast dating back 120,000 years. In addition to examining the fossilized turtle shells, the scientists also examined the shells of living turtles.

From each layer of seabed, the scientists randomly selected five complete, unbroken fossilized shells. Each shell was care­fully prepared, measured, and photographed. A bit of each shell was then clipped off and sent to a laboratory for radiocarbon dat­ing to determine the precise age of each shell.

Study /

All of the living turtles had a distinct band of hexagonal Study 2 scutes (bony plates) running the length of their shells, from head For each shell, the surface area of the shell, the to tail. The fossilized shells' sCUles were not visible to the naked shell's bridge (the part of the shell linking the upper eye; however upon application of a particular dye, a similar band plates), and the total number of scutes were recorded of scutes from head to tail was observed in every shell. ure 1).

SculeS extending greater than .!. of the length of the shell gmwg,8 were labeled major (M), where scutes extending less than or :::::r:height

equal to .!. of the length of the shell were labeled minor (m).8 Figure I '['he pattern of scutes was recorded for each fossil. For each time

period, the percent of fossils exhibiting each pattern is given in For the shells of each age, the average of each Table 1. was calculated. The results are presented in Figure 2.

201i I 1,296 ACT Practice Questions

20~~--~'~~-'---T--~ 120 100 80 ~ 40 20 0

age of shells (thOusands of years) e 3.2 . .,-------------,

QI -=­ 2.8 eo ..c::0' .~ ~~ .8 ;: cu ~

2.4

2.0 ·c .t:> 1.6+---,---.--..-,-~..____,..____1

120 100 80 60 40 20 0 age of shells (thousands of years)

:;-- 700-r--------------, - e]l .e 680 '" <':III.l

~ ~ 660G8 ~ ~ 640

~ +---T---~--~--~--~~ 120 100 80 60 40 20 0

age of shells (thousands of years)

Figure 2

a layer of seabed determined to be 250,000 years old. the scientists found fragments of twelve turtle shells. but

complete. intact shells. Which of the following is the likely reason this layer of seabed was not included in

studies?

250.000 years is too old to obtain an accurate radio­carton date. Shells that were 250,000 years old would have been irrel ~vant to the studies. Accurate measurements of the dimensions of the shells could have been impossible 10 obtain. The ,cientists would not have been able to accurately detelmine the color of the shells.

regHd to the descriptions given in Study I, the shells the M-M-m-m-M band of scutes probably most

resembled which of the following?

@)HO® ~)JO ®

3. Acc~rding to the results of Study 2, how do the average number of scutes and the average bridge height of living turtles of the Opulasian Peninsula compare to those of the turtles of the Opulasian Peninsula from 120,000 years ago? For the living turtles:

A. both the average number of scutes and the average bridge height are larger.

B. both the average number of scutes and the average bridge height are smaller.

C. the average number of scutes is larger and the average bridge height is smaller.

D. the average number of scutes is smaller and while the average bridge height is larger.

4. Suppose, in Study I, the scientists had found another seabed layer with fossilized shells that were radiocarbon dated and found to be 86,000 years old. Based on the results of Study I, the scute pattern percents for the group of shells would most likely have been closest to which of the following?

M-m-M-M-m M-M-m-m-M M-m-M-m-M F. 100% 0% 0% G. 50% 25% 25% H. 36% 61% 4% J. 26% 69% 5%

5. In Study 2, the average shell surface area of fossilized turtle shells that were 80,000 years old was closest to:

A. 670cm2

B. 680cm2

C. 690cm2

D. 700cm2

6. Which of the following statements best describes how Study 1 differed from Study 2 ?

F. In Study I, the scientists examined 3 characteristics re­garding the shape and size of turtle shells; but in Study 2. the scientists examined the frequency of occurrence of different patterns of scutes on turtle shells.

G. In Study 1, the scientists examined the frequency of occurrence of different patterns of scutes on turtle shells; but in Study 2, the scientists examined the envi­ronment in which turtles live.

H. In Study I, the scientists examined the frequency of occurrence of different patterns of scutes on turtle shells; but in Study 2, the scientists examined 3 char­acteristics regarding the shape and size of turtJe shells.

J. In Study I, the scientists examined 3 characteristics regarding the shape and size of turtle shells; but in Study 2. the scientists examined the environment in which turtles live.

Science Practice I 207

SCIENCE REASONING TEST 35 Minutes-40 Questions

DIRECTIONS: There are seven passages in the following section. Each passage is followed by several questions. After reading a passage, choose the best answer to each question and blacken the corresponding oval on your answer document. You may refer to the passages as often as necessary.

You are NOT permitted to use a calculator on this test.

Passage I

A study was conducted regarding the fossil shells of a par­ticular species of turtle that lives off the coast of the Opula.<;ian Peninsula. Scientists discovered a continuous record of fossil­ized shells in the seabed off the coast dating back 120.000 years. In addition to examining the fossilized turtle shells. the scientists also examined the shells of living turtles.

From each layer of seabed, the scientists randomly selected five complete. unbroken fossilized shells. Each shell was care­fully prepared. measured, and photographed. A bit of each shell was then clipped off and sent to a laboratory for radiocarbon dat­ing to determine the precise age of each shell.

Study J

AU of the living turtles had a distinct band of hexagonal scutes (bony plates) running the length of their shells, from head to tail. The fossilized shells' scutes were not visible to the naked eye; however upon application ofa particular dye. a similar band of scutes from head to tail was observed in every shell.

Scutes extending greater than .! of the length of the shell 8

were labeled major (M), where scutes extending less than or

equal to .! of the length of the shell were labeled minor (m).8

The pattern of scutes was recorded for each fossil. For each time

period, the percent of fossils exhibiting each pattern is given in

Table l.

2116 I 1.296 ACT Practice Questions

Study 2

For each shell. the surface area of the shell. the shell's bridge (the part of the shell linking the upper plates). and the total number of scutes were recorded ure I).

upper plate

7':>---~Ibridge~ height bri~ J()W;plate

Figure 1

For the shells of each age, the average of each was calculated. The results are presented in Figure 2.

c

~ 4Or-----------------------,

~ 35 ~~ ~'O 30cu .... ~ ~a 25-1---­

20~~--~---r__r--~~ 120 [00 SO 60 40 20 0

age of shells (thousands of years)

! 3.2.,--··----------,

2.S ~.a t: .~ 2.4 ~~ :os ~ 2.0

·c 1.6f---.----.--....,--,-----,,....-.-j .c 120 [00 SO 60 40 20 0

age of shells (thousands of years) ~ 700.---------------,_. e

"Ql -36S0 ~; ~

~b ~ 660 f~ cu <I.. U

~ ~ 640 ~ +---~.--~--~--T_--~~

120 100 80 60 40 20 0 age of shells (thousands of years)

Figure 2

a layer of seabed determined to be 250,000 years old, scientists found fragments of twelve turtle shells, but complete, intact shells. Which of the following is the

Iil:ely reason this layer of seabed was not included in studies?

25C,000 years is too old to obtain an accurate radio­carbon date. Shells that were 250,000 years old would have been irre evant to the studies. Accurate measurements of the dimensions of the shells could have been impossible to obtain. The scientists would not have been able to accurately determine the color of the shells.

reg,lrd to the descriptions given in Study I, the shells the .VI-M-m-m-M band of scutes probably most

resembled which of the following?

3. AccQrding to the results of Study 2, how do the average number of scutes and the average bridge height of living turtles of the Opulasian Peninsula compare to those of the turtles of the Opulasian Peninsula from 120,000 years ago? For the living turtles:

A. both the average number of scutes and the average bridge height are larger.

B. both the average number of scutes and the average C\bridge height are smaller. fJ.i.:,.,Ithe average number of scutes is larger and the average

bridge height is smaller. D. the average number of scutes is smaller and while the

average bridge height is larger.

4. Suppose, in Study I, the scientists had found another seabed layer with fossilized shells that were radiocarbon dated and found to be 86,000 years old. Based on the results of Study I, the scute pattern percents for the group of shells would most likely have been closest to which of the following?

M-m-M-M-m M-M-m-m-M M-m-M-m-M F. 100% 0% 0% G. 50% 25% 25%

36% 61% 4% 26% 69% 5%cE>

5. In Study 2, the average shell surface area of fossilized turtle shells that were SO,ooo years old was closest to:

A. 670cm2

Iil. 6S0cm2

C. 690cm2

D. 700cm2

6. Which of the following statements best describes how Study 1 differed from Study 2 ?

F. In Study [. the scientists examined 3 characteristics re­garding the shape and size of turtle shells; but in Study 2, the scientists examined the frequency of occurrence of different patterns of scutes on turtle shells.

G. In Study I, the scientists examined the frequency of occurrence of different patterns of scutes on turtle shells; but in Study 2, the scientists examined the envi­ronment in which turtles live.

H. In Study I, the scientists examined the frequency of occurrence of different patterns of scutes on turtle shells; but in Study 2. the scientists examined 3 char­acteristics regarding the shape and size of turtle shells. o In Study I, the scientists examined 3 characteristics regarding the shape and size of turtle shells; but in Study 2, the scientists examined the environment in which turtles live.

Science Practice I 207

cladogram below describes the evolutionary rela­ioru~bil)S of some reptiles. Each branching point repre­

the common ancestor of the branches. The more the common ancestor, the closer the relationship is

om,luc:n;;u to be. Dates, in millions of years, represent time of transition from each era to the next. Base

answers only on the information in the diagram.

m ,­

2. The turtles are unique, of this group, in that:

(F) they are the only reptiles with a hard shell formed of ribs.

(G) they are not closely related to any other sur­viving reptile.

(H) they are not related to any other reptiles. (J) they have existed unchanged for over 245 mil­

lion years.

Of the following pairs, in, which pair are the two forms most closely related?

(A) Ornithischian dinosaurs and lizards (B) Birds and mammals (C) Crocodiles and ichthyosaurs (D) Birds and crocodiles

14. One outstanding feature of the record is that:

(F) there was a mass extinction at the end of the Cretaceous.

(G) there are now far more reptiles than mammals or birds.

(H) about 200 million years ago there was a major radiation of reptiles into a variety of new forms.

(J) the snakes and lizards became distinct about 140 million years ago.

Science Reasoning Review and Practice 415

15. Of all the groups shown, only the birds and the mammals are known to be warm-blooded. How can this be interpreted?

(A) It is possible that the ancestral archosaur may also be warm-blooded.

(B) Warm-bloodedness is an ancestral character that has survived in these two lines.

(C) The diagram as given may be wrong, since the fact that these birds and mammals share this character indicates a close relationship.

(D) Warm-bloodedness is a useful property that may arise more than once, independently.

16. If a geologist reports finding a fossil feather in a rock layer 220 million years old, how might his colleagues initially react?

(F) Revise the cladogram to place the origin of the birds at an earlier date.

(G) Suggest a careful reexamination of the evi­dence for the date of the rock.

(H) Take this as proof that an early Saurischian dinosaur had feathers.

(J) Reject the report because it conflicts with known data of the origin of birds.

) 2. (G) The turtles have no ancestor in common with all the other reptiles later than the earliest reptile of all. F is wrong because the cladogram gives no infonnation about shells in reptiles. H is wrong because there is a common ancestor, although it is in the long-distant past. J is wrong because the cladogram gives no infonnation about the way the various reptiles have changed.

13. (D) The common ancestor ,of the birds and crocodiles is an ancestral archosaur, about 220 million years ago', All of the other pairs have no common ancestor later than the stem reptiles, in the Pennian.

14. (F) Many of the lines in the diagram disappeared at the end of the Cretaceous. G is wrong because no infonnation is given about the relative abundance of the different life fonns. H is wrong because the major radiation took place long before 245 million years ago. J is wrong because this event is not a major feature of the whole story.

(0) A and B are wrong because it would be most unlikely that a character would survive in two distantly related fonns and not in any of the others. C is wrong because the cladogram depends on many characters, not just one. Independent evolution of a useful character is the most likely explanation.

(G) This discovery cannot be rejected out of hand, but it suggests a really drastic revision of current theories, con­flicting with much other evidence. It would have to be reviewed by others.