• University of California, Santa Barbara

• BIOLOGY AP

AP® Biology Exam

Which of the following observations best supports

the hypothesis that a large object collided with

Earth in a period of time associated with a mass

extinction?

(A) A species found only in Australia resembles

a species found only in North America.

(B) An analysis of radiation reaching Earth from

outer space suggests that water might have

existed on distant planets.

(C) A fossil of an extinct species of mammal is

found to have morphological characteristics

that are similar to those of a living nocturnal

mammal.

(D) Iridium, which is common in meteorites but

rare on Earth, is found in sedimentary rock

that contains the last appearance of many

species in the fossil record.

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2. Which of the following observations best

represents a mutualistic relationship?

(A) Some bacteria and fungi obtain their nutrients

by enzymatically digesting larger

organisms.

(B) Chloroplasts in green algae provide sugars

for use in cellular metabolism.

(C) Hermit crabs utilize empty sea snail shells to

protect themselves from predators.

(D) Flowers produce nectar that bees gather to

make honey, and in the process the bees

pollinate the flowers.

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3. A blue-flowered African violet of unknown

ancestry self-pollinated and produced 50 seeds.

These seeds germinate and grow into flowering

plants. Of these plants, 36 produce blue flowers

and 14 produce pink flowers. What is the best

explanation for the pink-flowered offspring?

(A) Blue flowers are incompletely dominant to

pink flowers.

(B) Pink flower color is a trait recessive to blue

flower color.

(C) Pink flower color is the result of somatic

mutations in the flower color gene.

(D) A previous generation of the blue-flowered

parent must have included 50 percent pinkflowered plants.

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4. While there is only one species of Galapagos

Island tortoise, there are several subspecies.

Larger islands with more wet highlands have lush

vegetation near the ground. Tortoises there tend to

have high-domed shells and shorter necks, which

restrict upward head movement. They also have

shorter limbs. They are the heaviest and largest

of the subspecies.

Smaller, drier islands are inhabited by tortoises

with longer necks and limbs and with shells that

are elevated above the neck, which allow them

to browse taller vegetation.

Based on the information given, which of the

following is a plausible explanation for the

ancestry of the tortoise subspecies?

(A) The subspecies share a recent common

ancestor whose neck length, shell shape,

and leg length were intermediate between

the two subspecies.

(B) The tortoises with shorter legs and necks

were most easily preyed on as young

animals by the rats that were introduced,

so they survived only on a few islands.

(C) Random mutations coupled with the

inheritance of acquired characteristics

resulted in distinct subspecies.

(D) Individuals with different adaptations in shell

shape and leg length best exploited the food

resources and left more surviving offspring

on each island