n 1. When a single population evolves into
two populations that cannot interbreed
anymore, speciation has occurred.
n 2. Darwin’s theory of natural selection
explained the process by which organisms
become well-adapted to their
n 3. A group of organisms that can mate
with each other to produce (fertile)
offspring is known as a(n) species.
n 4. The fossil record provides information
about organisms that lived in the past.
n 5. In selective breeding, humans select
organisms with desirable traits that will be
passed from one generation to another.
n 6. A(n) adaptation helps an organism
survive better in its environment.
n 7. Populations of insects and bacteria can
evolve quickly because they usually have a
short generation time.
n 8. Fossils are commonly found in
n A. sedimentary rock.
n 9. The fact that all organisms have DNA as
their genetic material is evidence that
n B. all organisms may have descended from a
n 10. Charles Darwin puzzled over
differences in the ______ of the different
species of Galapagos finches.
n b. beaks
n 11. Darwin observed variations among
individuals within a population, but he did
not realize that these variations were
n C. differences in genes.
n 12. Identify two ways that organisms can
be compared to provide evidence of
evolution from a common ancestor.
n 1)Living organisms can be compared in terms
of body structures with other living organisms
and with organisms from the fossil record.
2)Also, the DNA of living organisms can be
n 14. Why are some animals more likely to
survive to adulthood than other animals
n Those animals that are better adapted to the
conditions of their environment, including
competition with other organisms, are more
likely to survive to adulthood.
n 16. Outline an example of the speciation
n A single population of squirrels may have
been separated by the Grand Canyon. Over
many generations, they adapted to their
different environments and became very
different. Even though they look similar, they
are no longer able to interbreed.
n Another example
n In a lizard population there was variation in leg size
which affected climbing ability. Some lizards were
able to climb trees while others remained on the
ground. Over many generations, the 2 groups of
lizards adapted to their environments and became
different in many ways even though they still looked
similar. Eventually, they could no longer interbreed.
n 21. Using the graphs in the book, what is
the most common birth weight?
n About 7 pounds
n 22. At which birth weight is an infant most
likely to survive?
n About 7 pounds
n 23. How do the principles of natural
selection help explain why there are more
deaths among babies whose birth weights
are low than among babies whose birth
weights are average?
n The infants who are best adapted to survive
birth are those that weigh about 7 pounds.
n What is ecological succession:
n A series of progressive changes in plant and
animal life in an area that leads to a climax
n What is a climax community?
n A relatively stable community of organisms
that results from ecological succession
n List 3 ways primary succession and
secondary succession are different.
n 1)Primary succession begins with no soil;
secondary succession begins with soil.
n 2)They have different pioneer species.
n 3)Secondary succession occurs faster.
n List 1 identifying characteristic of each of the 5
classes of vertebrates.
n 1)Mammalia: warm-blooded; hair or fur;
n 2)Aves: warm-blooded; feathers; hollow bones
n 3)Reptilia: cold-blooded; scales; lay eggs on
n 4)Amphibia: cold-blooded; live part of life in
water & part on land; lay eggs in water
n 5)Pisces: cold-blooded; live in water
n Snowshoe hares experience a change in fur
color from brown in summer to white in winter.
How do you think fur color would be different if
the snowshoe hare moved to a warmer climate
year-round for many generations?
n Those hares whose genes allowed them to keep their
brown fur longer, would be better adapted and would
survive to reproduce. This trait would become more
and more common. Eventually, the population would
have brown fur all year long.
n Some scientists believe that leopard frogs in North
America came from a common species. Today, leopard
frogs from different parts of the continent can no longer
interbreed. Which statement describes the best
explanation for this change?
n A. Mating with another species of frogs causes genetic
n B. Climate changes over time cause species extinction, which
can result in a very small gene pool.
n C. Mating with different populations throughout North America
causes unique species to form.
n D. Geographic isolation from other populations can result in
n Arctic foxes have thick fur on the bottom of its paws.
Red foxes do not. Which evidence of species variation
does the difference in feet represent?
n A. Parasites caused the red fox to lack fur on paw bottoms.
n B. Landforms can sometimes isolate animals in a population.
n C. Climates require different adaptations for animals to survive.
n D. Different diets caused the arctic fox to have fur on the
bottom of its paws.
n Sometimes physical separation due to mountains or
distance can cause organism originally of the same
species to adapt to new environments that may cause
them to no longer be able to interbreed. Which
statement describes the best explanation for this
n A. Climate changes cause extinction.
n B. Mating with another species causes mutations.
n C. Geographic isolation from other populations can result in
n D. Mating with different species causes new species to form.