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Test Bank Biology The Dynamic Science 4th Edition Solution 1 INTRODUCTION TO BIOLOGICAL CONCEPTS AND RESEARCH Chapter Outline WHY IT MATTERS 1.1 WHAT IS LIFE? CHARACTERISTICS OF LIVING ORGANISMS Life on Earth exists at several levels of organization, each with its own emergent properties. Living organisms contain genetic information that governs their structure and function. Living organisms engage in metabolic activities. Energy flows and matter cycles through living organisms. Living organisms compensate for changes in the external environment. Living organisms reproduce, and many undergo development. Populations of living organisms change from one generation to the next. 1.2 BIOLOGICAL EVOLUTION Darwin and Wallace explained how populations of organisms change through time. Mutations in DNA are the raw materials that allow evolutionary change. Adaptations enable organisms to survive and reproduce in the environments where they live. 1.3 BIODIVERSITY AND THE TREE OF LIFE Researchers traditionally defined species and grouped them into successively more inclusive hierarchical categories. Today biologists identify the trunks, branches, and twigs on the tree of life. Three domains and several kingdoms form the major trunks and branches on the tree of life. Biologists often use model organisms to study fundamental biological processes. 1.4 BIOLOGICAL RESEARCH Biologists confront the unknown by conducting basic and applied research.
The scientific method helps researchers crystallize and test their ideas. Biologists conduct research by collecting observational and experimental data. Researchers often test hypotheses with basic questions that allow the development of hypotheses and controlled experiments. When controlled experiments are unfeasible, researchers employ null hypotheses to evaluate observational data. Molecular tools allow researchers to explore genes, genomes, and proteomes. Scientific theories are grand ideas that have withstood the test of time. Curiosity and the joy of discovery motivate scientific research.
Learning Objectives 1.1 Describe the characteristics of living organisms and their responses to environmental changes. 1.1.1 Describe the different levels of hierarchy through which the organization of life extends. 1.1.2 Explain the importance of deoxyribonucleic acid. 1.1.3 Describe the metabolic processes of photosynthesis and cellular respiration. 1.1.4 Illustrate how energy in the ecosystem flows from the sun to producers to consumers and then to decomposers. 1.1.5 Explain how living organisms detect environmental changes and use compensating responses. 1.1.6 Illustrate the processes involved in the life cycle of an organism. (Analyze) 1.1.7 Explain how populations change with each new generation. (Understand) 1.2 Discuss the three truths about the living world that the evolutionary process reveals. 1.2.1 Outline the conclusions drawn by Darwin and Wallace to explain biological evolution. 1.2.2 Explain the importance of DNA mutations in evolution. 1.2.3 Explain how organisms benefit from adaptations. 1.3 Discuss the importance of traditional classification and phylogenetic trees. 1.3.1 Compare the hierarchical categories used in traditional classification. 1.3.2 Discuss the importance of phylogenetic trees in the study of evolutionary pathways of different organisms. 1.3.3 Classify the three domains of species identified by biologists. 1.3.4 Discuss the importance of model organisms in research. 1.4 Explain the fundamentals of biological research. 1.4.1 Discuss the importance of basic research and applied research. 1.4.2 Summarize the scientific method. 1.4.3 Differentiate between observational data and experimental data. 1.4.4 Demonstrate the use of hypotheses, controls, and experimental variables. 1.4.5 Illustrate how researchers use null hypotheses. 1.4.6 Describe how molecular techniques have revolutionized biological research. 1.4.7 Explain the meaning of a scientific theory. 1.4.8 Debate the motivations for scientific research.
Key Terms cell
unicellular organisms
population
ecosystem
emergent properties
multicellular organisms
community
biosphere
deoxyribonucleic acid (DNA)
consumers
order
hypothesis
decomposers
class
null hypothesis
nucleotides
homeostasis
phylum
variables
genome
reproduction
kingdom
predictions
genes
inheritance
domain
alternative hypotheses
ribonucleic acid (RNA)
development
phylogenetic trees
control
proteins
life cycle
prokaryotes
experimental variable
gene expression
biological evolution
eukaryotes
replicates
messenger RNA (mRNA)
artificial selection
organelles
genomics
transcription
natural selection
model organisms
proteomics
translation
mutations
biological research
proteome
ribosomes
adaptations
basic research
bioinformatics
metabolism
species
applied research
systems biology
photosynthesis
genus
scientific method
scientific theory
cellular respiration
scientific name
observational data
primary producers
family
experimental data
Lecture Outline Why It Matters A. Countless organisms exist all over the world. 1. Animals, plants, and even bacteria interact and rely on one another to exist. 2. Organisms live, interact, and die every second of every day. B. Biology is the science of life. 1. Biology answers questions regarding the beginnings of life, how life persists, and how life is changing. 2. Biologists conduct research to better understand living systems. 1.1
What Is Life? Characteristics of Living Organisms A. Living organisms and inanimate objects have fundamental differences (Figure 1.1). 1. Living organisms have particular atoms and molecules that are organized and interact in specific ways. 2. Living organisms gather energy and materials from their surroundings to build new biological molecules. 3. Living organisms grow, maintain their structure, respond to environmental changes, produce new offspring, and change through generations. B. Life on Earth exists at several levels of organization, each with its own emergent properties (Figure 1.2). 1. Cells are the smallest units of life that can survive and reproduce. a. Unicellular organisms, such as bacteria, are those made of one cell. b. Multicellular organisms, such as plants and animals, are made of many cells interacting together. 2. Populations are groups of similar organisms that live together in the same place. 3. Communities are made of the many populations of organisms that live in a certain place together. 4. Ecosystems include communities and the nonliving environmental factors in which they interact. 5. At the highest level, the biosphere includes all ecosystems existing in the world. C. Living organisms contain genetic information that governs their structure and function. 1. DNA (deoxyribonucleic acid) is the fundamental molecule that distinguishes living from nonliving matter (Figure 1.3). a. DNA is used as a blueprint to make RNA (ribonucleic acid) (Figure 1.4). b. Information in RNA is used to make protein (Figure 1.4). c. Proteins carry out most activities of life, including the synthesis of all other biological molecules (Figure 1.4). D. Living organisms engage in metabolic activities. 1. Metabolism describes the activities a cell undergoes to obtain energy and use that energy to maintain itself, grow, and reproduce. 2. Metabolism includes chemical reactions to assemble, alter, and disassemble molecules as needed. a. Photosynthesis is the process in which plants capture energy from the sun and store energy as sugar (Figure 1.5). b. Cellular respiration is the process in which most organisms break down molecules to release energy for their use. E. Energy flows and matter cycles through living organisms. 1. Light from the sun supports most life on Earth. a. Primary producers use sunlight to produce energy used by all other living organisms. b. Consumers feed on the complex molecules manufactured by producers (Figure 1.6). c. Decomposers, such as some bacteria and fungi, feed on the dead remains of organisms. 2. Energy flows from the sun to the many organisms existing on Earth. a. Transfer of energy from one organism to another is not 100% efficient. b. Some energy is lost as heat during the flow from one organism to another. F. Living organisms compensate for changes in the external environment. 1. Living organisms have receptors on their cells or body that detect either internal or external conditions. a. Skin receptors detect changes in temperature and send signals to your brain. b. Signals make you shiver when you are cold and sweat when you are hot.
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Most organisms have mechanisms to maintain homeostasis, a steady internal condition maintained by responses that compensate for changes in the external environment. Living organisms reproduce, and many undergo development. 1. Reproduction is the process in which parent organisms produce offspring. 2. Parent organisms pass on copies of their DNA to offspring, resulting in offspring that resembles them. a. The transmission of DNA from one generation to the next is called inheritance. 3. Multicellular organisms undergo development, a series of programmed changes that transform them from egg to adult organism. a. Moths begin as eggs, hatch into caterpillar larval stages, and then spin a cocoon where they eventually develop into an adult moth (Figure 1.7). b. The sequential stages through which an organism develops, grows, maintains itself, and reproduces is referred to as the life cycle of that organism. Populations of living organisms change from one generation to the next. 1. Although most organisms resemble their parents, sometimes novel characteristics are seen in offspring. 2. Populations change from one generation to the next due to changes in DNA.
Biological Evolution A. Darwin and Wallace explained how populations of organisms change through time (evolve). 1. Fossil evidence demonstrates that extinct forms of organisms resemble living forms. 2. Fossil evidence also demonstrates that extinct forms of organisms were different than living forms. A. Darwin studied domesticated animals to demonstrate that organisms can change through time. a. Domesticated pigeons vary from the ancestral forms through the process of artificial selection of traits (Figure 1.8). b. Natural selection is the process of change in organisms associated with differential success in survival and breeding. B. Mutations in DNA are the raw materials that allow evolutionary change. 1. Functional units in DNA that code for protein are called genes. 2. Random changes in DNA (mutations) may change the development of an organism. 3. Beneficial mutations may give an organism an advantage (e.g., survival, reproductive ability) and may be passed on to future generations. C. Adaptations enable organisms to survive and reproduce in the environments where they live. 1. Characteristics that allow organisms to survive longer or reproduce more are called adaptations. 2. Michael Nachman and his colleagues studied coloration in pocket mice and could associate cryptic coloration with survival and reproduction (Figure 1.9). 3. Nachman also determined that differences in DNA are attributed to difference in coloration. 1.3 Biodiversity and the Tree of Life A. Researchers traditionally defined species and grouped them into successively more inclusive hierarchical categories. 1. Species are groups of organisms with similar structure, biochemistry, and behavior such that they can successfully interbreed. 2. A genus is a group of organisms that share common recent ancestry. 3. Each species is assigned a two-part scientific name that identifies its genus and species. a. Scientific names are always written in italics or else underlined. b. The genus name is always capitalized, followed by the species name written in lowercase letters. 4. Other levels by which organisms are grouped based on similarity include family, order, class, phylum, kingdom, and domain (Figure 1.10). B. Today biologists identify the trunks, branches, and twigs on the tree of life. 1. Biologists now use DNA sequence and other biological molecules to trace evolutionary pathways called the phylogenetic tree. 2. Phylogenetic trees shows how an ancestor gave rise to its descendants, producing the great diversity of life. 3. A phylogenetic tree often parallels the traditional hierarchical classification. 4. The tree of life is now reconstructed from data on the genetics, structure, metabolic processes, and behavior of living things, as well as from fossil data.
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1.4
Three domains and several kingdoms form the major trunks and branches on the tree of life. 1. The three main domains of all organisms are the Bacteria, Archaea, and Eukarya (Figure 1.11). a. Bacteria and Archaea are described as prokaryotes based on their cellular structure (Figure 1.12a). b. Eukarya are described as eukaryotes based on their cellular structure (Figure 1.12b). 2. Bacteria are unicellular organisms that are microscopic in size (Figure 1.13a). a. Bacteria are producers or decomposers. b. Bacteria are similar in structure to Archaea, with simple cellular organization of DNA and internal structures. 3. Archaea are unicellular organisms that are microscopic in size (Figure 1.13b). a. Archaea are producers or decomposers and can live in extreme environments. b. Archaea have some structural differences from the Bacteria and undergo a primitive form of photosynthesis. c. Archaea have similarities with the Eukarya, including DNA and RNA organization and processes of protein synthesis. 4. Eukarya include all organisms on Earth that cannot be classified as Bacteria or Archaea. The four kingdoms of Eukarya are the “Protists,” Plantae, Fungi, and Animalia (Figure 1.13c). a. Protists are either unicellular or multicellular organisms, and include the protozoans and algae. b. Plantae are multicellular organisms that carry out photosynthesis. c. Fungi are either unicellular or multicellular organisms, and include the yeasts and molds. d. Animals are multicellular organisms that exist as consumers. Biologists often use model organisms to study fundamental processes. a. Model organisms usually have rapid development, short life cycles, and small adult size. b. Using model organisms from difference branches of the Tree of Life results can be applied to many species.
Biological Research A. Biologists confront the unknown by conducting basic and applied research. 1. Basic research is conducted to explain natural phenomena and advance our collective knowledge of living systems. 2. Applied research is conducted with the goal of solving specific practical problems. B. The scientific method helps researchers crystallize and test their ideas. 1. Scientific method refers to acquiring knowledge by making observations, working out an explanation, and then testing the explanation by presenting evidence based on a carefully designed experiment (Figure 1.14). 2. Scientists share their observations and explanations through publication of their work. C. Biologists conduct research by collecting observational and experimental data. 1. Observational data is based on biological structures or the details of biological processes and often provides information about systems that have not yet been well studied. 2. Experimental data describes the results of careful manipulation of a system and tries to answer “why” or “how” systems work. D. Research often begins with basic questions that allow the development of hypotheses and controlled experiments. 1. Research often begins with a solid base of carefully observed and described facts. 2. A hypothesis is a working explanation of observed facts that can be experimentally tested to determine if it is true or false. 3. Hypotheses may be used to explain the relationship between variables, environmental factors that may differ among places, or organismal characteristics that may differ among individuals. 4. Hypotheses yield predictions, statements about what the researcher expects to happen to one variable if another variable changes. 5. Experiments result in scientists either rejecting or confirming a hypothesis; however, no amount of data can prove beyond a doubt that a hypothesis is correct. 6. Scientists use controls, conditions that tell you what you might expect in the absence of experimental manipulation, to help verify a hypothesis (Figure 1.15).
7. Since biological organisms often vary in their response to certain conditions, nearly all experiments in biology include replicates, multiple subjects that receive the same experimental treatment or the same control treatment. E. When controlled experiments are unfeasible, researchers employ null hypotheses to evaluate observational data. 1. If the systems under study are too large or complex for experimental manipulation, researchers develop null hypotheses—statements of what would be observed if the hypothesis being tested is wrong— to evaluate data. 2. Paul Hertz used copper models of lizards to test his null hypothesis that lizards do not regulate body temperature and select perching sites at random rather than based on their desire to regulate body temperature (Figure 1.16). F. Molecular tools allow researchers to explore genes, genomes, and proteomes. 1. Scientists can modify organisms by deleting or replacing some genes or by adding others. 2. Genomics sf the branch of biology that characterizes entire genomes. 3. Many scientists use a reductionist approach in their work. 4. Systems biologists utilize a more holistic approach; integrating aspects of many fields (Figure 1.17). G. Scientific theories are grand ideas that have withstood the test of time. 1. Following repeated experimental tests and years of research, a hypothesis may become regarded as a scientific theory. 2. Scientific theories are different than common everyday theories, which are often speculative or suspect. H. Curiosity and the joy of discovery motivate scientific research. 1. Most research is conducted to achieve a specific goal; however, many researchers engage in research simply because it is exciting. 2. Research must be done honestly, using sound scientific methods, to provide knowledge about us and our world.
Suggestions for Presenting the Material Many students believe introductory biology entails trudging through many different facts that are unrelated. This chapter gives an overview of modern biology. Highlight the importance of DNA in all living things, and how the information carried in DNA codes for different messages in different organisms. Stress to students the importance of knowing the processes that account for biodiversity as they are presented in this chapter. Utilize the research done by Hoekstra and Nachman to emphasize how there are gene expression patterns, mutations, and selection that all combine to produce the pattern we see today in populations. This will also serve as a springboard for other chapters later in the text. Use the experimental examples given at the end of the chapter to help students understand that scientific research is not a black box. Once students begin to use and understand the material in the book, they should be helped to understand that they too are scientists.
Visual Learning Tips The excitement of biology can easily be conveyed through the use of pictures. A well-timed photo montage in which different pictures—ranging from cells, to representatives of all the groups of organisms, to different habitats—are shown every 10 seconds during the chapter’s introductory lecture is one way to easily pique interest. This could be done at the beginning of the class period or during the coverage of biodiversity. Show the animation on the DNA double helix to help students understand the unity of information storage across taxa.
Use the animation showing the flow of energy to explain how organisms are related with both the abiotic and biotic variables in their environment. This can be shown in conjunction with Figure 1.6. The animation on animal development is a good bridge to explain how variation is not only present between individuals, but within individuals. Utilize Figure 1.9 after the animation to show how selection acts on variation. Compare and contrast experimental and observational research using Figures 1.15 and 1.16. Use the BBC Motion Gallery clip on Cloned Meat (Biology Video Library; ISBN 978-1-111-57446-8) to bring light to the current debate on the topic. In addition, this will emphasize the utility of the scientific method.
Educational Websites The following websites include additional information and interesting facts relevant to the material presented in Chapter 1. http://www.aboutdarwin.com/ http://www.visionlearning.com/library/module_viewer.php?mid=45 http://www.tolweb.org/tree/ http://evolution.berkeley.edu/evolibrary/article/evo_30
Classroom Discussion Why It Matters Ask students to give examples of interactions between organisms they have observed recently in their lives. The beginning section mentions many different examples of animals in their environments. Divide the class into small groups and ask them to list all the things they think may live in different types of habitat (give a different habitat to each group). Remind students not to forget about bacteria and plants. Students can generate a large list, and this helps students realize that they already know something about biology. It is also possible to choose organisms from one of the lists when going over classification during lecture. This can also be used in a lab or discussion section. In order to help students understand what requirements are necessary for life, discuss the characteristics of viruses to illustrate the differences between living and nonliving.
Additional Discussion Ideas Display graphs from papers with the associated abstract and ask students, working in groups, to determine the hypothesis tested and the results that can be determined from the graph. Ask students to contemplate the presence of antibiotic-resistant strains of bacteria. Emphasize mutation and selection during the discussion. Ask students to estimate the total number of species in a given group of organisms (e.g., plants, sharks, etc.). Reinforce the idea of artificial selection by polling students on the breeds of dogs they have as pets.
Classroom and Laboratory Enrichment Show a small video clip from any of the BBC series, Life of Mammals, etc. Try to pick something obscure that students have not had experience with or learned about in previous courses. This is a great way to generate curiosity and interest in the course. Have students work in small groups to generate hypotheses and create methods for testing their hypotheses. Give them the bare minimum of information and let them try this on their own. Information given could be from a video clip, or you could describe a characteristic of an organism and have them ask questions and then generate a hypothesis. Have students look around the room and list all the characteristics that account for the variation seen among humans.
Term Paper Topics, Library Activities, and Special Projects Have students go to the AKC website and look at the number of dog breeds that are AKC certified. Have them choose one breed and then do a small project on which breeds were originally mixed to get the one of interest. Also have students determine which of the characteristics in the parent breeds were artificially selected to result in the new breed. Have students research the lives of Darwin and Wallace, and list some of the personal experiences that led them to their conclusions on the theory of evolution by natural selection. Have students do a research project on extremophile bacteria and archaea. The final product could be a small written paragraph and a list of citations of research on these organisms.
Suggested Readings Hoekstra H.E., K.E. Drumm, and M.W. Nachman. Ecological genetics of adaptive color polymorphism in pocket mice: geographic variation in selected and neutral genes. EVOLUTION 58 (6): 1329–1341, 2004.
Singer, Emily. “Biology’s Big Problem: There is Too Much Data to Handle.” Wired. October, 2013 (http://www.wired.com/2013/10/big-data-biology/).
Possible Ideas for Think Outside the Book Students can learn more about the Tree of Life web project by visiting this web site: http://tolweb.org/tree/. Students can learn more about the scientific method and the richness of the scientific enterprise by visiting this web site, maintained by researchers at the University of California at Berkeley: http://undsci.berkeley.edu/
Possible Responses to Discuss Concepts 1.
Viruses are not cells, so they lack that emergent property of life. While they do complete a metabolism of sorts, they do not do so independently of a living cell. They do evolve, have DNA or RNA, and are diverse. From a strictly philosophical standpoint, scientists have chemically synthesized active polio virus using a DNA synthesizer and some tissue culture cells.
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The first test would be to determine by microscopy if the substance has cells associated with it. If there are no cells, it isn’t a living organism. If it has complex macromolecules, such as carbohydrates, proteins, or DNA, it is likely the product of a living organism. If it is of simple composition, which is relatively unlikely given its gelatinous nature, it is inert matter.
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A positive control enables scientists to determine that their test conditions repeat the observed phenomenon. If the positive control isn’t positive, the experimental and test results aren’t valid. The negative control is designed to give a null result for comparison.
Possible Response to Design an Experiment The control group would be salmon fed a typical diet. Test groups would have diets consisting of naturally pigmented foods, such as carrots, beets, or green vegetables. Positive control groups would be fed diets containing food coloring (orange, red, and green). After several weeks, the salmon would be killed and their external color as well as meat color would be assessed.
Possible Response to Apply Evolutionary Thinking The pesticide is an environmental stressor. Those insects naturally resistant will survive the pesticide and produce offspring, which will have the genes for resistance as well. As the allele frequency goes up for the resistance gene, more insects will survive.
Answers to Video Quiz 1. b 2. b 3. established the scientific method
Answers to Interpret the Data Anolis gundlachi does not regulate its body temperature. The graphs show that lizards perch in patches of sun at about the same rate as randomly positioned models and that lizards and models exhibit similar distributions of body temperatures. These data suggest that this lizard species perches at random with respect to environmental factors that might influence its body temperature.
Answers to Think Like a Scientist Figure 1.15: To test the effects of two experimental variables simultaneously, you would need to design an experiment that had experimental and control groups for both variables (that is, fertilizer and water). One group might receive both fertilizer and water; a second group would receive fertilizer but no water; a third group would receive water but no fertilizer; and a fourth group would receive neither fertilizer nor water. You could then compare the results of the four treatments to see the effects of both experimental variables, alone and in combination, on your plants. Figure 1.16: The temperature is not very variable among the shaded sites in this environment. Most of the models were in shaded sites, and the temperatures of the shaded sites are clustered around 19° to 20°C.