Campbell Biology - Chapter 1 - Evolution, Themes, and Scientific Inquiry PDF

Chapter 1 Evolution, the Themes of Biology, and Scientific Inquiry © 2021 Pearson Education, Inc.  The light, dappled fur of this beach mouse (Peromyscus polionotus) allows it to blend into its habitat —brilliant white sand dunes, dotte...

Chapter 1 Evolution, the Themes of Biology, and Scientific Inquiry © 2021 Pearson Education, Inc.  The light, dappled fur of this beach mouse (Peromyscus polionotus) allows it to blend into its habitat —brilliant white sand dunes, dotted with sparse clumps of beach grass along the Florida seashore. Mice of the same species that inhabit nearby inland areas are much darker, blending with the soil and vegetation where they live © 2021 Pearson Education, Inc. Figure 1.1a © 2021 Pearson Education, Inc. Figure 1.1b CONCEPT 1.1: The study of life reveals unifying themes Biology is the scientific study of life We recognize life by what living things do Biology is a subject of enormous scope © 2021 Pearson Education, Inc.  There are five unifying themes in Biology – Organization – Information – Energy and Matter – Interactions – Evolution © 2021 Pearson Education, Inc. © 2021 Pearson Education, Inc. Figure 1.2 Theme: New Properties Emerge at Successive Levels of Biological Organization Life can be studied at different levels, from molecules to the entire living planet This enormous range can be divided into different levels of biological organization Reductionism is an approach that reduces complex systems to simple components that are manageable to study © 2021 Pearson Education, Inc. Figure 1.3 © 2021 Pearson Education, Inc. Emergent Properties Emergent properties result from the arrangement and interaction of parts as complexity increases Emergent properties characterize nonbiological entities as well – For example, a functioning bicycle emerges only when all of the necessary parts connect in the correct way © 2021 Pearson Education, Inc.  The reductionist approach studies the isolated components of the living system To explore emergent properties, biologists complement reductionism with systems biology, analysis of the interactions among the parts of a biological system Systems biology can be used to study life at all levels © 2021 Pearson Education, Inc. Structure and Function At each level of the biological hierarchy we find a correlation between structure and function Analyzing a biological structure gives us clues about what it does and how it works Conversely, knowing the function of something provides insight into its structure and organization © 2021 Pearson Education, Inc. Figure 1.UN01 © 2021 Pearson Education, Inc. The Cell: An Organism’s Basic Unit of Structure and Function The cell is the smallest unit of organization that can perform all activities required for life The cell theory states that all living organisms are made from cells Every cell is enclosed by a membrane that regulates passage of materials between the cell and its environment The cells of bacteria and archaea are prokaryotic, while all other forms of life are composed of eukaryotic cells © 2021 Pearson Education, Inc.  A eukaryotic cell has membrane-enclosed organelles, the largest of which is usually the nucleus By comparison, a prokaryotic cell is simpler and usually smaller and does not contain a nucleus or other membrane-enclosed organelles © 2021 Pearson Education, Inc. Figure 1.4 © 2021 Pearson Education, Inc. Theme: Life’s Processes Involve the Expression and Transmission of Genetic Information Within cells, structures called chromosomes contain genetic material in the form of DNA (deoxyribonucleic acid) © 2021 Pearson Education, Inc. Figure 1.5 © 2021 Pearson Education, Inc. DNA, the Genetic Material Each chromosome contains one long DNA molecule with hundreds or thousands of genes Genes are the units of inheritance They encode information for building the molecules synthesized within the cell The genetic information encoded by DNA directs the development of an organism © 2021 Pearson Education, Inc. Figure 1.6 © 2021 Pearson Education, Inc.  The molecular structure of DNA accounts for its ability to store information Each DNA molecule is made up of two long chains arranged in a double helix Each chain is made up of four kinds of chemical building blocks called nucleotides and abbreviated A, G, C, and T © 2021 Pearson Education, Inc. Figure 1.7 © 2021 Pearson Education, Inc.  For many genes, the sequence provides the blueprint for making a protein Protein-encoding genes control protein production indirectly DNA is transcribed into RNA, which is then translated into a protein Gene expression is the process of converting information from gene to cellular product © 2021 Pearson Education, Inc. Figure 1.8 © 2021 Pearson Education, Inc. Genomics: Large-Scale Analysis of DNA Sequences An organism’s genome is its entire “library” of genetic instructions Genomics is the study of whole sets of genes in one or more species Proteomics is the study of whole sets of proteins and their properties The entire set of proteins expressed by a given cell, tissue, or organ is called a proteome © 2021 Pearson Education, Inc.  The genomics approach depends on – “High-throughput” technology, which yields enormous amounts of data – Bioinformatics, which is the use of computational tools to process a large volume of data very rapidly – Interdisciplinary research teams © 2021 Pearson Education, Inc. Theme: Life Requires the Transfer and Transformation of Energy and Matter The input of energy from the sun and the transformation of energy from one form to another make life possible The chemical energy generated by plants and other photosynthetic organisms (producers) is passed along to consumers Consumers are organisms that feed on other organisms or their remains © 2021 Pearson Education, Inc. Figure 1.9 © 2021 Pearson Education, Inc.  When organisms use energy to perform work, some energy is lost to the surroundings as heat As a result, energy flows through an ecosystem, usually entering as light and exiting as heat Chemicals cycle within an ecosystem, where they are used and then recycled © 2021 Pearson Education, Inc. Theme: From Molecules to Ecosystems, Interactions Are Important in Biological Systems Interactions between the components of the system ensure smooth integration of all the parts This holds true equally well for molecules in a cell and the components of an ecosystem © 2021 Pearson Education, Inc. Molecules: Interactions Within Organisms Interactions between components that make up living organisms—organs, tissues, cells, and molecules—are crucial to their smooth operation Many biological processes can self-regulate through a mechanism called feedback © 2021 Pearson Education, Inc.  In feedback regulation, the output, or product of a process, regulates that very process The most common form of regulation in living organisms is negative feedback, in which the response reduces the initial stimulus A less common form of regulation is positive feedback, in which an end product speeds up its own production © 2021 Pearson Education, Inc. Figure 1.10 © 2021 Pearson Education, Inc. Ecosystems: An Organism’s Interactions with Other Organisms and the Physical Environment At the ecosystem level, each organism interacts with other organisms These interactions may be beneficial or harmful to one or both of the organisms Organisms also interact continuously with the physical factors in their environment, and the environment is affected by the organisms living there © 2021 Pearson Education, Inc. Figure 1.11 © 2021 Pearson Education, Inc.  Each organism interacts continuously with physical factors in its environment Humans interact with our environment, sometimes with dire consequences Over the past 150 years, humans have greatly increased the burning of fossil fuels and the release of carbon dioxide (CO2) into the atmosphere The resulting global warming is just one aspect of climate change © 2021 Pearson Education, Inc.  Wind and precipitation patterns are also shifting Extreme weather events such as storms and droughts are occurring more often As habitats deteriorate, plant and animal species shift their ranges to more suitable locations For some, there is insufficient suitable habitat Populations of many species are shrinking in size or even disappearing © 2021 Pearson Education, Inc. Figure 1.12 © 2021 Pearson Education, Inc. CONCEPT 1.2: The Core Theme: Evolution accounts for the unity and diversity of life An understanding of evolution helps us to make sense of everything we know about life on earth The scientific explanation for both the unity and diversity of organisms is evolution, the concept that living organisms are modified descendants of common ancestors An abundance of evidence supports the occurrence of evolution © 2021 Pearson Education, Inc.  “Nothing in biology makes sense except in the light of evolution”—Theodosius Dobzhansky © 2021 Pearson Education, Inc. Classifying the Diversity of Life Approximately 1.8 million species have been identified and named to date Each species is given a two-part name: The genus, to which the species belongs, and a species name unique to that species E.g., Homo sapiens, is the name of our species Estimates of the total number of species that actually exist range from 10 million to over 100 million © 2021 Pearson Education, Inc. The Three Domains of Life Organisms are currently divided into three domains, named Bacteria, Archaea, and Eukarya The prokaryotes include the domains Bacteria and Archaea © 2021 Pearson Education, Inc.  Domain Eukarya includes all eukaryotic organisms Domain Eukarya includes the four subgroups – Plants, which produce their own food by photosynthesis – Fungi, which absorb nutrients – Animals, which ingest their food – Protists © 2021 Pearson Education, Inc.  Protists are the most numerous and diverse eukaryotes These are mostly single-celled organisms They are classified into several groups Some protists are less closely related to other protists than they are to plants, animals, or fungi © 2021 Pearson Education, Inc. Figure 1.13 © 2021 Pearson Education, Inc. Unity in the Diversity of Life A striking unity underlies the diversity of life; for example, – DNA is the universal genetic language common to all organisms – Unity is evident in the similar skeletons of different animals The history of life as documented by fossils and other evidence is the saga of a changing Earth, billions of years old © 2021 Pearson Education, Inc. Figure 1.14 © 2021 Pearson Education, Inc. Figure 1.15 © 2021 Pearson Education, Inc. Charles Darwin and the Theory of Natural Selection Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859 Darwin made two main points – Species showed evidence of “descent with modification” from common ancestors – “Natural selection” is the mechanism behind descent with modification Darwin’s theory explained the duality of unity and diversity © 2021 Pearson Education, Inc. Figure 1.16 © 2021 Pearson Education, Inc. Figure 1.17 © 2021 Pearson Education, Inc.  Darwin observed that – Individuals in a population vary in their traits, many of which seem to be heritable – More offspring are produced than survive, and competition is inevitable – Species generally suit their environment © 2021 Pearson Education, Inc.  Darwin reasoned that – Individuals with traits that are best suited to their environment are more likely to survive and reproduce – Over time, more individuals in a population will have the advantageous traits Evolution occurs as the unequal reproductive success of individuals © 2021 Pearson Education, Inc.  The natural environment “selects” for the propagation of beneficial traits Darwin called this process natural selection © 2021 Pearson Education, Inc. Figure 1.18 © 2021 Pearson Education, Inc.  Natural selection results in the adaptation of organisms to the circumstances of their way of life and their environment For example, bat wings are an example of adaptation © 2021 Pearson Education, Inc. Figure 1.19 © 2021 Pearson Education, Inc. The Tree of Life The shared anatomy of mammalian limbs reflects the inheritance of the limb structure from a common ancestor Fossils and other evidence corroborate anatomical unity in support of mammalian descent with modification © 2021 Pearson Education, Inc.  Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species – For example, the finch species of the Galápagos Islands are descended from a common ancestor Evolutionary relationships are often illustrated with treelike diagrams that show ancestors and their descendants © 2021 Pearson Education, Inc. Figure 1.20 © 2021 Pearson Education, Inc. CONCEPT 1.3: In studying nature, scientists form and test hypotheses The word science is derived from Latin and means “to know” Inquiry is the search for information and explanations of natural phenomena Scientists use a process of inquiry that includes making observations, forming logical hypotheses, and testing them © 2021 Pearson Education, Inc. Exploration and Observation Biology begins with careful observation Observations can reveal valuable information about the natural world Biologists also rely heavily on the published contributions of fellow scientists They build on the foundation of existing knowledge Identifying relevant publications is easier than in the past, thanks to indexed and searchable electronic databases © 2021 Pearson Education, Inc. Gathering and Analyzing Data Recorded observations are called data – Qualitative data often take the form of recorded descriptions – Quantitative data are expressed as numerical measurement, organized into tables and graphs © 2021 Pearson Education, Inc. Figure 1.21 © 2021 Pearson Education, Inc.  Inductive reasoning derives generalizations from a large number of specific observations Careful observations and data analyses, along with generalizations reached by induction, are fundamental to our understanding of nature © 2021 Pearson Education, Inc. Forming and Testing Hypotheses In science, a hypothesis is an explanation, based on observations and assumptions, that leads to a testable prediction It must lead to predictions that can be tested by making additional observations or by performing experiments An experiment is a scientific test, carried out under controlled conditions © 2021 Pearson Education, Inc.  For example: – Observation: Desk lamp doesn’t work – Question: Why does’t the desk lamp work? – Hypothesis 1: The bulb is burnt out – Hypothesis 2: The bulb is not screwed in properly Both these hypotheses are testable © 2021 Pearson Education, Inc. Figure 1.22 © 2021 Pearson Education, Inc. Deductive Reasoning Deductive reasoning uses general premises to make specific predictions Initial observations may give rise to multiple hypotheses We can never prove that a hypothesis is true, but testing it in many ways with different sorts of data can significantly increase our confidence in it © 2021 Pearson Education, Inc. Questions That Can and Cannot Be Addressed by Science A hypothesis must be testable – For example, a hypothesis that ghosts fooled with the desk lamp cannot be tested Supernatural and religious explanations are outside the bounds of science © 2021 Pearson Education, Inc. The Flexibility of the Scientific Process The scientific method is an idealized process of inquiry However, very few scientific inquiries adhere rigidly to this approach Backtracking may be necessary partway through the process In other cases, observations may be too puzzling to prompt well-defined questions, until further studies are complete © 2021 Pearson Education, Inc. Figure 1.23 © 2021 Pearson Education, Inc. A Case Study in Scientific Inquiry: Investigating Coat Coloration in Mouse Populations Color patterns of animals vary widely in nature, sometimes even between members of the same species Two populations of mice of the same species (Peromyscus polionotus), but with different color patterns reside in different environments The beach mouse lives on white sand dunes with sparse vegetation; the inland mouse lives on darker soil © 2021 Pearson Education, Inc. Figure 1.24 © 2021 Pearson Education, Inc.  The two types of mice match the coloration of their habitats Natural predators of these mice are all visual hunters Francis Bertody Sumner hypothesized that the color patterns had evolved as adaptations to protect the mice from predators In 2010, Hopi Hoekstra and a group of students tested this hypothesis © 2021 Pearson Education, Inc.  The researchers predicted that mice that did not match their habitat would be preyed on more heavily than mice that did match the surroundings They built models of mice, painted them to match one of the surroundings, and placed equal numbers of each type of model in each habitat They then recorded signs of predation The data fit the key prediction of the camouflage hypothesis © 2021 Pearson Education, Inc. Figure 1.25 © 2021 Pearson Education, Inc. Variables and Controls in Experiments In a controlled experiment, an experimental group (the non-camouflaged mice in this case) is compared with a control group (the camouflaged mice) Experimental variables are features or quantities that vary in an experiment – The independent variable is the one that is manipulated by the researchers – The dependent variable is the one predicted to be affected in response © 2021 Pearson Education, Inc. Theories in Science In the context of science, a theory is – Broader in scope than a hypothesis – General enough to lead to many new, testable hypotheses – Supported by a large body of evidence in comparison to a hypothesis © 2021 Pearson Education, Inc. CONCEPT 1.4: Science benefits from a cooperative approach and diverse viewpoints Most scientists work in teams, which often include graduate and undergraduate students Good communication is important in order to share results through seminars, publications, and websites Research papers are not published until vetted by colleagues in the “peer review” process © 2021 Pearson Education, Inc. Building on the Work of Others Scientists check each other’s claims by performing similar experiments If experimental results are not repeatable, the original claim will have to be revised It is not unusual for different scientists to work on the same research question © 2021 Pearson Education, Inc.  Scientists cooperate by sharing data about model organisms (for example, the fruit fly Drosophila melanogaster) There are several other popular model organisms as well Biologists approach interesting questions from different angles © 2021 Pearson Education, Inc. Science, Technology, and Society The goal of science is to understand natural phenomena The goal of technology is to apply scientific knowledge for some specific purpose Science and technology are interdependent © 2021 Pearson Education, Inc.  The combination of science and technology can have dramatic effects on society – For example, the discovery of DNA by James Watson and Francis Crick allowed for advances in DNA technology such as testing for hereditary diseases Debates on technology center more on “should we do it” than “can we do it” © 2021 Pearson Education, Inc.  Ethical issues that arise from new technology can have as much to do with politics, economics, and cultural values as with science and technology © 2021 Pearson Education, Inc. Figure 1.26 © 2021 Pearson Education, Inc. The Value of Diverse Viewpoints in Science Many important inventions have occurred where a mix of different cultures ignited new ideas – For example, the printing press relied on innovations from China (paper and ink) and Europe (mass production in mills) Science benefits from a diversity of backgrounds and viewpoints among its practitioners The more voices heard, the more robust, valuable, and productive the scientific interchange © 2021 Pearson Education, Inc. Figure 1.UN09 © 2021 Pearson Education, Inc.