1. Theory of Evolution and Natural Selection
Baseline
15. The diagram below is a cladogram that represents an evolutionary tree. Archaeopteryx
fossils discovered in Germany show what scientists believe was a featered dinosaur.
Ornithishian Sauropods T.Rex Aechaeopteryx ?
Enter diagram of question #15
The next species in the evolutionary tree would modt likely belong to which class?
A. Birds
B. Dinosaurs
C. Mammals
D. Reptiles
25. Zebras stripes are thought to be an adaptation that has been passed down to prevent
zebras from being seen by the tsetse fly. The tsetse fly is part of the zebras natural habitat and
transmits deadly diseases to zebras. What would most likely happen to a zebra born in the wild
without stripes?
A. the zebra would adapt to a different habitat.
B. the zebra would become part of a new zebra species.
C. the zebra would not live long enough to pass on the trait.
D. the zebra would pass the color trait to the next generation.
27. A scientist is studying fossils of a great white shark. The scientist measures the size o the
teeth and finds the sharks 10,000 years ago had qan average tooth size of 8 centimeters, while
modern great white sharks have an average tooth size of only 4 centimeters. What can the
scientist conclude from this data?
A. The energy required to produce large teeth placed ancient sharks at a disadvantage.
B. Over time, the average tooth size of preditors has decreased.
C. Larger teeth do not give the modern shark a great advantage.
D. Great white sharks no longer rely on their teeth to survive.
36. In the early nineteenth century, a French naturalist named Jean-Baptiste Lamarck
developed a theory. He said that an orgamism passes on to its offspring the traits it requires
during the lifetime in response to the environment. For instance, Lamarck’s theory explains why

2. giraffes have long necks. It is because their shorter-necked ancestors spent their lives stretching
to reach food.
Enter diagram of question #36
Which study would best test whether Lamarck’s theory is valid?
A. exposing wheat seeds to extreme cold and then abserving how well they grow in cold
conditions
B. crossing pea plants with different colored flowers and observing the colors of the flowers
of their offspring
C. determining if the children of bodybuilders are more muscular than the other children of
people who do not lift weights
D. isolating a population of straight-winged fruit flies, allowing them to mate, and then
observing the wing type of the offspring
37. As the best-adapted memebers of a species produce offspring and pass on their favorable
characteristics to succeeding generations, what happens to the population of the species as a
whole?
A. The best-adapted members will soon become another species.
B. The best-adapted members will overpopulate the environment, leading to extinctions.
C. The entire population will gradually become more similar to the best-adapted members.
D. The entire population will stop evolving once the favorable characteristic is present in all
members.
43. Scientists can use evidence to estimate how often a particular segment of DNA in a
particular organism will undergo mutation. They can then locate the analogous segment in a
related organism, tabulate the differences between the segments, and use this “molecular clock”
to do which of the following?
A. compare the adaptive fitness of each species in different habitats
B. predict the possible future forms that the organisms might take as the undergo mutations
C. make an educated guess as to how long ago two species diverged from a common
ancestor
D. evaluate whether the mutations seen in the organisms’ DNA will be maintained in the
population
60. Scientists working in the field of comparative embryology use special microscopes to
study homologous structures, such as backbones, in the embroyos of different organisms. A

3. scientist observes embryos of three different animals and draws their body structure and
appearence as shown below.
EARLY EMBRYOS
Fish Reptile Bird
Enter diagram of question #60
What part of the theory of evolution might a comparison of the embryos shown above support?
A. Evolution happens slowly over time except in punctuated bursts marked by increases in
mutations.
B. The proportions of individuals with a certain trait remains constant over time within
populations.
C. The fittest members of different species survive because of advantageous adaptations.
D. Modern organisms evolved from common ancestors in an evolutionary chain.