1. giraffes use their extremely long necks to reach the leaves high up on acacia trees, which other animals cannot reach, giving them a food source for which they have few competitors. what can you conclude about natural selection from this observation?

a) giraffe necks get longer over a lifetime of stretching, and their offspring inherit the longer necks of their parents.
b) all giraffes are born with short necks and, eating acacia leaves causes them to stretch over a lifetime.
c) other animals will mimic the giraffe and grow longer necks.
d) the giraffes with the longest necks survive and produce offspring.

2. based on fossilized evidence, there are scientific claims made about the evolution of certain species. if a scientist studying the fossils of a specific species had a hypothesis other than what was currently accepted, what steps should be taken to have the alternative hypothesis considered?

a) since the original hypothesis is untestable given the circumstances, another one is more likely to be correct.
b) if an alternative hypothesis sounds plausible it could be used in place of the original hypothesis.
c) the scientist should publish the alternative hypothesis in a popular magazine to gain public support.
d) it is useful to test alternative hypotheses and know that they are incorrect.

3. darwin noticed differences in the beak shapes of finches on the various islands of the galapagos and surmised that they all might have evolved from a common ancestor on the mainland. if darwin had known about molecular biology, a field of study that did not exist at the time he lived, how might he have used it to test his hypothesis?

a) he could have done dna tests on the birds to see how closely they were related.
b) he could have checked to see if they shared similar cellular structures indicating their common ancestry.
c) he could have used modern tools to make more accurate measurements of beak shape and size.
d) he could have genetically engineered finches with extreme beak shapes to see how they survived.

4. the insulin used to treat people with diabetes is commonly produced by inserting the dna sequence for human insulin into a bacterium. the insulin the bacterium produces using that sequence is then harvested. in fact, dna sequences from virtually any living organism could be inserted into a bacterium and the bacterium would be able to use the sequences to make the same proteins that the original organism did. in what way does this provide evidence for evolution?

a) since bacteria are able to use dna from other organisms, they must have evolved from them as a common descendant.
b) bacteria must be less evolved than higher organisms since they can still make proteins from the dna of other organisms.
c) since the genetic code is the same across species, these species must have inherited it from a common ancestor.
d) since foreign dna was added to the bacteria, it evolved beyond higher organisms.

5. which of the following is the best example of evolution occurring? (2 points)

a) some of the trees in places with harsh winters lose their leaves in the fall.
b) strains of bacteria can become immune to antibiotics that once killed them effectively.
c) viruses can attack single-celled organisms as well as multicellular organisms.
d) lions and cows both have hair covering their bodies and give birth to live offspring.

6. coral snakes are brightly colored highly venomous snakes with red, yellow, and black bands along their bodies. another species of snake, called the scarlet king snake, has similar bands of red, black, and yellow. which of the following describes the conditions that resulted in a large population of king snakes with these types of markings?

a) king snakes and coral snakes relied on similar food sources that contributed to their unique coloring.
b) since king snakes with these markings were avoided by predators, they were able to survive to pass on this trait to offspring.
c) coral snakes mated with king snakes often enough to produce another species of king snake with the red, black, and yellow.
d) overproduction of offspring increased the likelihood that the genetic mutation leading to these bands would spontaneously occur.