Questions and Answers of Biology Concepts Investigations

Review the structures of nucleic acids and proteins in chapter 2. What chemical elements had to have been in primordial “soup” to generate these organic molecules?
Suppose that plants in the San Francisco Bay area and in southern Chile have the same seed-dispersal method. Scientists determine that the evolutionary divergence of these plants happened long before
Why is it important for evolutionary biologists to be able to distinguish between homologous and analogous anatomical structures?
What hypothesis did Alfred Russel Wallace make about the unique birds and mammals on either side of an imaginary line in the Malay Archipelago? How did the eventual explanation for Wallace’s line
Index fossils represent organisms that were widespread but lived during relatively short periods of time. How might index fossils be useful in relative dating?
The bubonic plague swept through western Europe in 1348. Suppose researchers use 14C dating on the skeletons of suspected plague victims, and they discover that about 50% of the original amount of
Describe six types of fossils and how they form. What present environmental conditions might preserve today’s organisms to form the fossils of the future?
Jellyfish Lake, located on the Pacific island of Palau, is home to millions of jellyfish. Many years ago, sea levels dropped and the jellyfish were trapped in the basin. The lake contains no
Which mechanisms of evolution cause random changes in allele frequencies? Which cause nonrandom changes?
Write a paragraph that describes the connections among the following terms: gene, nucleotide, allele, phenotype, population, genetic variation, natural selection, and evolution.
How does variation arise in an asexually reproducing population? A sexually reproducing population?
Explain how understanding evolution is important to medicine, agriculture, and maintaining the diversity of organisms on Earth.
Refer to figure 12.24 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction. When has evolution occurred in life’s history?
Which of the groups in figure 1.9 represent clades? Which groups do not represent clades? Explain your answers.Figure 1.9 DOMAIN BACTERIA DOMAIN ARCHAEA DOMAIN EUKARYA • Celils lack nuclel
List the major events of the Precambrian supereon and of the Paleozoic, Mesozoic, and Cenozoic eras.
The antibiotic streptomycin kills bacterial cells but not eukaryotic cells; diphtheria toxin kills eukaryotic cells but not bacteria. Which of these two substances do you predict would kill
The amoeba Pelomyxa palustris is a single-celled eukaryote with no mitochondria, but it contains symbiotic bacteria that can live in the presence of O2. How does this observation support the
List a logical sequence of events that starts with an early prokaryote and ends with a modern multicellular eukaryote.
List three ways that studying the history of life helps us understand life’s current diversity, and predict how diversity might change in the future.
Refer to figure 15.31 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction and add life’s history, DNA evidence, and
Explain how the origin of self-replicating molecules was critical to life’s origin.
On figure 14.20, circle a monophyletic group, a paraphyletic group, and a polyphyletic group. Describe the qualities that define how each group is classified.Figure 14.20 • Light bones • 3-toed
Why do species become extinct? Choose a species that has recently become extinct, and describe some possible evolutionary consequences to other species that interacted with that species before its
How does natural selection predict a gradualistic mode of evolution? Does the presence of fossils that are consistent with punctuated equilibrium mean that natural selection does not occur?
Refer to figure 14.28 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction and then add phylogenetic trees, species,
What type of reproductive barrier applies to each of these scenarios?a. Water buffalo and cattle can mate, but the embryos die early in development.b. Scientists try to mate two species of dragonfly
Some genes are more alike between human and chimp than other genes are from person to person. Does this mean that chimps are humans or that humans with different alleles are different species? What
How do biologists use sequences of proteins and genes to infer evolutionary relationships?
Many species look similar as embryos. What causes them to appear different as adults? Why does the study of development give insights into evolutionary relationships?
Explain why a researcher might combine evidence from fossils and from the anatomy of existing organisms when creating an evolutionary tree.
Suppose that collaborating research teams found fossils of the same extinct species in eastern South America and western Africa. What can the researchers conclude about the age of these fossils
What types of information are used to hypothesize how species are related to one another by descent from a shared ancestor? Give an example of how multiple types of evidence can support one another.
Refer to figure 13.25 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction. What diagrams do scientists use to visualize
Explain the significance of the geologic timescale in the context of evolution.
Fraggles are mythical, mouselike creatures that live underground beneath a large vegetable garden. Of the 100 Fraggles in this population, 84 have green fur, and 16 have gray fur. A dominant allele F
Explain how harmful recessive alleles can persist in populations, even though they prevent homozygous individuals from reproducing.
How did James Hutton, Georges Cuvier, Georges-Louis Buffon, Jean Baptiste de Lamarck, Charles Lyell, and Thomas Malthus influence Charles Darwin’s thinking?
List and describe five mechanisms of evolution.
If a cell’s genome is analogous to a cookbook and a gene is analogous to a recipe, what is an analogy for preimplantation genetic diagnosis? For gene testing? For gene therapy?
Describe gene therapy, and explain the ethical issues that gene therapy presents.
In a 2013 investigation, researchers discovered that meat packaged as “100% beef ” in Europe actually contained traces of horse meat and pork. What DNA technology techniques might the researchers
Scientists are interested in cloning an extinct animal called the gastric brooding frog. This strange frog swallows its eggs and broods its young within its stomach. So far, scientists have
Unneeded genes in an adult animal cell are permanently inactivated, making it impossible for most specialized cells to turn into any other cell type. How does this arrangement save energy inside a
Why are entire genomes not used for DNA profiling?
Compare and contrast the use of the DNA polymerase enzyme in DNA sequencing and PCR.
Transgenic crops often require fewer herbicides and insecticides than conventional crops. In that respect, they could be considered environmentally friendly. Use the Internet to research the question
Explain how the ingredients in a PCR reaction tube replicate DNA.
Refer to figure 11.20 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction. Given DNA’s role in the cell, why do the basic
What techniques might researchers use to create transgenic bacteria that produce human growth hormone (a drug used to treat extremely short stature)?
Design an experiment using twins to determine the degree to which autism is genetic or environmental.
A species of ornamental fish comes in two colors; red is dominant and gray is recessive. Emily owns a red fish, and she wants to know its genotype. Therefore, she mates her pet with a gray fish. If
How do heart disease and cancer illustrate diseases that reflect both genetic and environmental influences?
In the following pedigree, is the disorder’s mode of inheritance autosomal dominant, autosomal recessive, or X-linked recessive? Explain your reasoning. 1 2 II 1 2 3 4 5 6 7 8 II 1 2 3 4 5 6 7
How do the pedigrees differ for autosomal dominant, autosomal recessive, and X-linked recessive conditions?
X inactivation explains the large color patches in calico cat fur and the smaller patches in tortoiseshell cat fur. In which type of cat do you expect X inactivation occurs earlier in development?
A family has an X-linked dominant form of congenital generalized hypertrichosis (excessive hairiness). Although the allele is dominant, males are more severely affected than females. Moreover, the
Would you expect dominant X-linked illnesses to affect women as often as men? Explain your answer.
In fraggles, males are genotype XY and females are XX. Silly, a male fraggle, has a rare X-linked recessive disorder that makes him walk backwards. He mates with Lilly, who is a carrier for the
Many men with “Y chromosome infertility” are unable to produce sperm. Do you think this condition is typically inherited? Explain your answer.
Three babies are born in the hospital on the same day. Baby X has type B blood; Baby Y has type AB blood; Baby Z has type O blood. Use the information in the following table to determine which baby
Explain how each of the following produces phenotypic ratios other than those Mendel observed: incomplete dominance, codominance, pleiotropy, epistasis.
Genes Q, R, and S are on the same chromosome. The crossover frequency between S and Q is 5%, the crossover frequency between Q and R is 30%, and the crossover frequency between R and S is 35%. Use
Consider two genes that are near each other on a chromosome. After a germ cell undergoes meiosis, are the gametes likely or unlikely to contain a recombinant chromatid for these two genes? Explain.
A fern with genotype AA Bb Cc dd Ee mates with another fern with genotype aa Bb CC Dd ee. What proportion of the offspring will be heterozygous for all genes? Assume the genes assort independently.
How does crossing over “unlink” genes?
Two lizards have green skin and large dewlaps (genotype Gg Dd).(a) If 32 offspring are born, how many of the offspring are expected to be homozygous recessive for both genes?(b) What proportion of
How did Mendel use evidence from monohybrid and dihybrid crosses to deduce his laws of segregation and independent assortment? How do these laws relate to meiosis?
Some people compare a homologous pair of chromosomes to a pair of shoes. Explain the similarity. How would you extend the analogy to the sex chromosomes for females and for males?
In Mexican hairless dogs, a dominant allele confers hairlessness. However, inheriting two dominant alleles is lethal; the fetus dies before birth. Suppose a breeder mates two dogs that are
List three genes (mentioned in this chapter or not) that do not affect physical appearance. Do these genes contribute to an organism’s phenotype?
Refer to figure 10.35 and the chapter content to answer the following questions.1. Compare the Survey the Landscape figure in the chapter introduction with the Pull It Together concept map. Explain
In rose bushes, red flowers (FF or Ff ) are dominant to white flowers ( ff ). A true-breeding red rose is crossed with a white rose; two flowers of the F1 generation are subsequently crossed. What
Select one gene mentioned in the chapter; then explain the link between an organism’s genotype (for that gene) and its corresponding phenotype. Make sure to use the term protein in your answer.
Provide examples to support or refute this statement: The products of meiosis are always haploid cells, whereas the products of mitotic division are always diploid cells.
How does spermatogenesis differ from oogenesis, and how are the processes similar?
What is the relationship between nondisjunction and aneuploidy?
List examples of abnormalities in chromosome number and structure. Explain how each relates to an error in meiosis.
In some animals, females can reproduce by themselves—that is, without males. In this process, called parthenogenesis, the young develop from unfertilized eggs. Use the Internet to find a species
Draw all possible metaphase I chromosomal arrangements for a cell with a diploid number of 8. How many unique gametes are possible for this species? Is this number an underestimate or an
Where do the members of each pair of homologous chromosomes in a diploid cell come from?
How are the members of a homologous pair similar and different?
What is the difference between haploid and diploid cells? Are your skin cells haploid or diploid? What about germ cells? Gametes?
Sketch the relationships among mitosis, meiosis, and fertilization in a sexual life cycle.
Describe a situation in which asexual reproduction might be more likely than sexual reproduction.
Refer to figure 9.24 and the chapter content to answer the following questions.1. Review section 9.5 and the Survey the Landscape figure in the chapter introduction. What two processes in meiosis I
Explain why evolution often selects traits that promote genetic diversity.
A protein called p53 promotes the expression of genes encoding DNA repair enzymes. Badly damaged DNA prompts p53 to trigger apoptosis, and the cell dies. Why might mutations in the gene encoding p53
Why do chemotherapy and radiation sometimes kill hair follicle cells, while leaving many other body cells unaffected?
In the early 1900s, scientists began to experiment with radiation as a cancer treatment. Many physicians who administered the treatment subsequently died of cancer. Why?
Suppose you learn of a study in which ginger slowed tumor growth in mice for 30 days. What questions would you ask before deciding whether to recommend that a cancer-stricken relative eat more ginger?
List the ways that binary fission is similar to and different from mitotic cell division.
Describe what will happen to a cell if interphase happens but mitosis does not.
If you draw on your skin with a permanent marker, the markings will fade in a couple of days. What does this simple demonstration reveal about cell division in your skin? What can you infer about
If a cell somehow skipped G1 of interphase during multiple cell cycles, how would the daughter cells change?
Sketch and describe the events that occur when a bacterial cell divides.
Obtain a rubber band and twist it as many times as you can. What happens to the overall shape of the rubber band? How is this similar to what happens to chromosomes as a cell prepares to divide? How
Tightly packed DNA cannot be used for protein synthesis. Why has evolution favored the histones and other proteins that help DNA fold into compact chromosomes?
Explain how cell division and cell death work together to form a functional multicellular organism.
Write and explain an analogy for each of these DNA replication enzymes: helicase, binding proteins, ligase.
Refer to figure 8.23 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction and then connect DNA and proteins to the Pull It

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