1. Two squirrel populations are prevented from mating only because they live on opposite sides of the Colorado River. This is an example ofA) reproductive isolationB) geographic isolationC) natural selectionD) adaptive radiation

2. Which factor is least likely to contribute to an increase in the rate of evolution?A) presence of genetic variations in a populationB) environmental selection of organisms best adapted to surviveC) chromosomal recombinationsD) a long period of environmental stability

3. Darwin’s theory of evolution is based onA) variation and natural selectionB) use and disuseC) spontaneous genetic mutationsD) transmission of acquired traits

4. In his studies of birds on the Galapagos Islands, Darwin observed that few bird varieties with similar beak size and shape inhabited a particular area. The limited number and similar varieties was most likely due toA) competition for the same foodB) the presence of a disease that attacks birds with similar beaksC) competition for a specific concentration of oxygen in the airD) the presence of an excessive number of autotrophs

5. What is the likely explanation for the branching pattern seen on a phylogenic tree as shown here?A) environmental changes influenced speciationB) no speciation occurred C) speciation occurred because of inbreedingD) environmental changes resulted in extinction

6. Traits that are least beneficial to a species tend to decrease in frequency from generation to generation because these traits usuallyA) have a high survival valueB) have a low survival valueC) affect only the older members of the populationD) are inherited by more individuals

7. After the industrial revolution, dark-colored moths outnumbered light-colored moths in certain regions of England. In the past 40 years, factories in these regions have added scrubbers and air purifiers to their smokestacks, and the relative number of light-colored moths has increased. The probable reason for this increase isA) the environment favored the survival of light-colored mothsB) the allele for light color became dominant over the dark color alleleC) overpopulation occurred and most of the light moths diedD) dark moths turned light to survive

8. The special characteristics that make an organism particularly well-suited to its environment are known asA) biotic factorsB) abiotic factorsC) adaptationsD) aggregates

9. Which statement about the individuals within a population that survive to reproductive age is consistent with Darwin’s theory of natural selection?A) they will perpetuate unfavorable changes in the speciesB) they are the ones best adapted to exist in their environmentC) they tend to produce fewer offspring than those that do not surviveD) they transmit characteristics acquired by use and disuse to their offspring

10. Natural selection can best be defined asA) elimination of the smallest organisms by the largest organismsB) survival of those organisms genetically best adapted to their environmentC) survival of the strongest organismsD) survival and reproduction of those organisms that occupy the largest area

11. Which factor has the greatest effect on the rate of evolution of animals?A) environmental changesB) asexual reproductionC) use and disuseD) vegetative propagation

12. Similarity in the skeletal structures of whales, bats and humans leads to the conclusion that theyA) have the same chromosome numberB) descended from a common ancestorC) belong to the same order of mammalsD) originated in the same environment

13. Which technique has been used by scientists to determine that the Earth is at least 4.5 billion years old?A) using x-rays to find fossils buried in the Earth’s crustB) using the electron microscope to observe fossils of prehistoric lifeC) comparing fossils found in the upper strata to fossils in lower rockD) radioactive dating of rocks in Earth’s crust

14. Which best describes adaptive radiation?A) more than one species evolve to fill a single nicheB) old species always become extinct when new species evolveC) species adapt to radioactive substances in their environmentsD) species evolve filling available niches

15. Based on Lamark’s theory of evolution, the human appendix decreased in size and lost its digestive function becauseA) development of useless organs conserved energyB) the appendix was not needed or used as a digestive organC) humans with small appendix were better adapted to their environmentD) inherited mutations caused the appendix to become useless

16. In 1889, Weisman, a German biologist conducted an experiment attempting to produce mice without tails. He cut the tails off adult mice and then permitted them to mate. All offspring had long tails. He repeated the experiment many times, always with the same results. This helped to disprove what concept?A) struggle for existenceB) survival of the fittestC) inheritance of acquired traitsD) overproduction in a species

17. Which statement is most consistent with the theory of evolution as stated by Lamarck?A) In a litter of puppies, the weakest one died.B) a cat that lost a toe produced a kitten missing a toe.C) a change in DNA structure produced longer tails in monkeys.D) the mutation rate of a bacterium increased under UV light.

18. The theory that birds and reptiles share common ancestry is supported by the evidence that they bothA) have evolved as separate groups at about the same timeB) show structural similarities during their developmentC) have similar environmental requirementsD) occupy similar niches

19. Scientists compared fossil remains of a species that lived 5,000 years ago with members of the same species living today. Scientists concluded that this species had changed very little over the entire time period. Which statement best accounts for this lack of change?A)The environment changed significantly and those offspring without favorable characteristics died.B) The environment changed significantly but the species had no natural enemies for a long time.C) The environment did not change and those offspring expressing new traits survived their enemies.D) The environment did not change and those offspring expressing new traits did not survive.

20. Similarities in bone structure among organisms supports the idea that they have a common ancestor, but differences in the bone arrangements support the hypothesis that these organismsA) are members of the same speciesB) all contain the same genetic informationC) may have descended from the same ancestorD) have adaptations to survive in different environments

21. Over a long period of time the organisms on an island changed so that they could no longer interbreed with the organisms on a neighboring island. This inability to interbreed is known asA) hybridizationB) artificial selectionC) reproductive isolationD) survival of the fittest

22. Which term describes appendages that may have different functions, but are similar in structure and are assumed to have the same evolutionary origin?A) mutations C) homozygousB) fossils D) homologous

23. According to one theory, similarities in embryos suggests common ancestry. As these embryos mature, they will most likelyA) develop in to aquatic animals with gillsB) develop the distinctive traits of their speciesC) show no similarities as adultsD) continue to closely resemble each other as adults

24. A small community that is heavily infested with mosquitoes was sprayed weekly with the insecticide DDT for several months. What is the most probable reason for the decreased effectiveness of the DDT?A) DDT caused mutations in their genesB) DDT was only sprayed onceC) Mosquitoes resistant to DDT lived and produced offspringD) DDT chemically reacted with the DNA of the mosquitoes

25. Beak structures differ between individuals of one species of bird. These differences most likely indicateA) the presence of a variety of food sourcesB) a large supply of one kind of foodC) a reduced rate of reproductionD) an abundance of predators