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Chapter 1 Introduction: Biology Today PowerPoint® Lectures for Campbell Essential Biology, Fifth Edition, and Campbell Essential Biology with Physiology, Fourth Edition – Eric J. Simon, Jean L. Dickey, and Jane B. Reece Lectures by Edward J. Zalisko © 2013 Pearson Education, Inc. Biology and Society: Biology All Around Us • We are living in a golden age of biology. • Scientists are studying a myriad of questions that are relevant to our lives. – How can errors in cell growth lead to cancer? – Genes that control cell growth undergo mutations. – How do plants trap solar energy? – Plants use special molecules that trap light energy. – How do living creatures form ecological networks and how do human activities disrupt them? – Overpopulation is the most important threat to our planet. © 2013 Pearson Education, Inc. Biology and Society: Biology All Around Us – How did the great diversity of life on Earth evolve from the first microbes and how does such evolution have an impact on human health? – Bacteria have evolved over many decades to resist antibiotics. – How do mutations in genes lead to disease? – Mutations in genes leads to differences in proteins that regulate biological function. – How can DNA—the molecular basis of heredity— be used in forensic investigations? – © 2013 Pearson Education, Inc. Differences in DNA of humans is unique to each individual. THE SCOPE OF LIFE The Properties of Life • Biology is the scientific study of life. • The study of biology encompasses – a wide scale of size from bacteria to blue whale and – a huge variety of life, both past and present. – 99.9% of all species to ever exist are now extinct © 2013 Pearson Education, Inc. Living things (organisms) show specific qualities: 1. Order – exhibit complex but organized organization Example: a simple pine cone showing unique geometry of seeds. © 2013 Pearson Education, Inc. 2. Regulation – organisms must regulate themselves based on internal and external changes Example: lizard adjusting temperature of its body © 2013 Pearson Education, Inc. 3. Growth and development – organisms grow and develop in a pattern specific to the species Example: newborn ostrich growing to an adult © 2013 Pearson Education, Inc. 4. Energy processing – organisms take in energy and emit energy as heat Example: puffin bird eats food for energy and maintains body temperature which it releases as heat © 2013 Pearson Education, Inc. 5. Response to the environment – organisms respond to internal and external stimuli Example: Venus flytrap capturing food © 2013 Pearson Education, Inc. 5. Reproduction – organisms make more of themselves Example: hippos make more of themselves © 2013 Pearson Education, Inc. 6. Evolution – species evolve over time based on survival and reproductive success Example: insect has evolved to look like a leaf © 2013 Pearson Education, Inc. Life at Its Many Levels • Biologists explore life at levels ranging from the biosphere to the subatomic particles. © 2013 Pearson Education, Inc. Figure 1.2-3 1 Biosphere 2 Ecosystems 3 Communities 4 Populations 5 Organisms 6 Organ Systems and Organs 9 Organelles 7 Tissues 10 Molecules and Atoms Atom Nucleus 8 Cells Biosphere – Planet Earth Ecosystem – living and non-living components with similar traits Community – more than one species living in a defined geographical location Population – members of a single species living in a particular area Organism – single member of a species Organ System – group of organs that achieve a common function Organ – group of different tissues that performs a specific function. Tissue – group of cells that perform a certain function. Cell – the fundamental unit of life on Earth Organelle – structure within a cell that performs a specific function. Nucleus 8 Cells 9 Organelles Molecule – consists of two or more elements Atom – fundamental unit of matter in the universe Atom 10 Molecules and Atoms Ecosystems • Each organism interacts continuously with its environment. – Organisms interact continuously with the living and nonliving factors in the environment. – All the living organisms in a specific area, along with all of the nonliving factors with which they interact, form an ecosystem. © 2013 Pearson Education, Inc. Ecosystems • The dynamics of any ecosystem depend on two main processes: – recycling of chemical nutrients and – flow of energy. • Within ecosystems – molecules are recycled but – energy flows in and out of it. © 2013 Pearson Education, Inc. Figure 1.3 Outflow of heat energy ECOSYSTEM Inflow of light energy Consumers (animals) Chemical energy (food) Producers (plants and other photosynthetic organisms) Cycling of nutrients Decomposers (in soil) Cells and Their DNA • The cell is the level at which the properties of life emerge. • Cells are the lowest level of structure that can perform all activities required for life. • All organisms are composed of cells. • Cells are the subunits that make up multicellular organisms such as humans and trees. © 2013 Pearson Education, Inc. Cells and Their DNA • All cells share many characteristics. – All cells are enclosed by a membrane that regulates the passage of materials between the cell and its surroundings. – Every cell uses DNA as its genetic information. – DNA is the instruction for a cell on how to make proteins. © 2013 Pearson Education, Inc. Cells and Their DNA • We can distinguish two major types of cells: 1. The prokaryotic cell – is simpler and smaller and – is represented by simple bacteria – does not have a nucleus that stores DNA 2. The eukaryotic cell is – subdivided by internal membranes into different functional compartments called organelles and – found in plants, animals, protists and fungi © 2013 Pearson Education, Inc. Figure 1.4 Prokaryotic cell (bacterium) Eukaryotic cell • Smaller • Simpler structure • DNA concentrated in • Larger • More complex Organelles nucleoid region, which is not enclosed by membrane • Lacks most organelles structure • Nucleus enclosed by membrane • Contains many types of organelles Nucleoid region Colorized TEM Nucleus Cells and Their DNA • All cells use DNA as the chemical material of genes, the units of inheritance that transmit information from parents to offspring. • A gene is a stretch of the DNA molecules that codes for the structure of a particular protein. • The chemical language of DNA – is common to all organisms and – consists of just four molecular building blocks with names that are abbreviated as A, G, C, T. © 2013 Pearson Education, Inc. Figure 1.5 The four chemical building blocks of DNA A DNA molecule Cells and Their DNA • Genetic engineering has transformed the pharmaceutical industry and extended millions of lives. • Scientists have taken advantage of the fact that DNA is common to all cells. • They have transplanted DNA from fluorescent jellyfish into a mouse. • They have transplanted human genes into yeast cells to produce human proteins to treat disease. © 2013 Pearson Education, Inc. Figure 1.6 Cells and Their DNA • The entire “book” of genetic instructions that an organism inherits is called its genome. • The nucleus of each human cell packs a genome that is about 3.2 billion chemical letters long. • The letters are abbreviated “ A T G and C” © 2013 Pearson Education, Inc. Life in Its Diverse Forms • Diversity is a hallmark of life. – The diversity of known life includes about 1.8 million species that biologists have identified and named. – Estimates of the total number of species range from 10 million to over 100 million. © 2013 Pearson Education, Inc. Figure 1.7 Grouping Species: The Basic Concept • Biodiversity can be beautiful but overwhelming. • Categorizing life into groups helps us deal with this complexity. • Taxonomy is the branch of biology that names and classifies species. – It formalizes the hierarchical ordering of organisms into broader and broader groups. © 2013 Pearson Education, Inc. https://www.youtube.com/watch?v=NRVJyUZoQo w The Three Domains of Life • The three domains of life are – Bacteria, – Archaea, and – Eukarya. • Bacteria and Archaea have prokaryotic cells. • Eukarya have eukaryotic cells. © 2013 Pearson Education, Inc. The Three Domains of Life • Eukarya include – Kingdom Plantae, – Kingdom Fungi, – Kingdom Animalia, and – Protists (multiple kingdoms). • Most plants, fungi, and animals are multicellular. • Protists are generally single-celled. © 2013 Pearson Education, Inc. The Three Domains of Life • These three multicellular kingdoms are distinguished by how they obtain food. – Plants produce their own sugars and other foods by photosynthesis. – Fungi are mostly decomposers, digesting dead organisms. – Animals obtain food by ingesting (eating) and digesting other organisms. © 2013 Pearson Education, Inc. DOMAIN ARCHAEA DOMAIN BACTERIA Figure 1.8a Figure 1.8b DOMAIN EUKARYA Kingdom Plantae Kingdom Fungi Kingdom Animalia Protists (multiple kingdoms) Unity in the Diversity of Life • Underlying the diversity of life is a striking unity, especially at the lower levels of biological organization. – For example, all life uses the genetic language of DNA. • Biological evolution accounts for this combination of unity and diversity. © 2013 Pearson Education, Inc. EVOLUTION: BIOLOGY’S UNIFYING THEME • The history of life is a saga of a constantly changing Earth billions of years old. – Fossils document this history. © 2013 Pearson Education, Inc. EVOLUTION: BIOLOGY’S UNIFYING THEME • Life evolves. – Each species is one twig of a branching tree of life extending back in time through ancestral species more and more remote. – Species that are very similar, such as the brown bear and polar bear, share a more recent common ancestor. © 2013 Pearson Education, Inc. Figure 1.10 Giant panda Spectacled bear Ancestral bear Sloth bear Sun bear Common ancestor of all modern bears American black bear Asiatic black bear Common ancestor of polar bear and brown bear Polar bear Brown bear 30 25 20 15 10 Millions of years ago 5 The Darwinian View of Life • The evolutionary view of life came into focus in 1859 when Charles Darwin published On the Origin of Species by Means of Natural Selection. © 2013 Pearson Education, Inc. The Darwinian View of Life • Darwin’s book developed two main points: 1. Species living today descended from a succession of ancestral species in what Darwin called “descent with modification,” capturing the duality of life’s – unity (descent) and – diversity (modification). 2. Natural selection is the mechanism for descent with modification. © 2013 Pearson Education, Inc. Natural Selection • Darwin was struck by the diversity of animals on the Galápagos Islands. • He thought that adaptation to the environment and the origin of new species were closely related processes. – As populations separated by a geographic barrier adapted to local environments, they became separate species. © 2013 Pearson Education, Inc. Figure 1.11a Darwin’s Inescapable Conclusion • Darwin synthesized the theory of natural selection from two observations that were neither profound nor original. – Others had the pieces of the puzzle, but Darwin could see how they fit together. © 2013 Pearson Education, Inc. Darwin’s Inescapable Conclusion • Observation 1: Overproduction and competition • Observation 2: Individual variation • Conclusion: Unequal reproductive success – It is this unequal reproductive success that Darwin called natural selection. – The product of natural selection is adaptation. • Natural selection is the mechanism of evolution. © 2013 Pearson Education, Inc. Figure 1.12 1 Population with varied inherited traits 2 Elimination of individuals with certain traits 3 Reproduction of survivors 4 Increasing frequency of traits that enhance survival and reproductive success Observing Artificial Selection • Artificial selection is the selective breeding of domesticated plants and animals by humans. • In artificial selection, humans do the selecting instead of the environment. © 2013 Pearson Education, Inc. Figure 1.13a (a) Vegetables descended from wild mustard Wild mustard Cabbage from end buds Brussels sprouts from side buds Kohlrabi from stems Kale from leaves Broccoli from flowers and stems Cauliflower from flower clusters Figure 1.13b (b) Domesticated dogs descended from wolves Gray wolves Domesticated dogs Observing Natural Selection • There are many examples of natural selection in action. – In Galápagos finches, beak size becomes better suited to the size and shape of available seeds. – Antibiotic-resistance in bacteria evolves in response to the overuse of antibiotics. © 2013 Pearson Education, Inc. Observing Natural Selection • Darwin’s publication of The Origin of Species fueled an explosion in biological research. – Evolution is one of biology’s best demonstrated, most comprehensive, and longest-lasting theories. – Evolution is the unifying theme of biology. © 2013 Pearson Education, Inc. https://www.youtube.com/watch?v=GhHOjC4oxh8 https://www.youtube.com/watch?v=0SCjhI86grU https://www.youtube.com/watch?v=lIEoO5KdPvg THE PROCESS OF SCIENCE • The word science is derived from a Latin verb meaning “to know.” – Science is a way of knowing, based on inquiry. – Science developed from our curiosity about ourselves and the world around us. © 2013 Pearson Education, Inc. THE PROCESS OF SCIENCE • There are two main scientific approaches: – Discovery science is mostly about describing nature. – Hypothesis-driven science is mostly about explaining nature. © 2013 Pearson Education, Inc. Discovery Science • Science seeks natural causes for natural phenomena. – This limits the scope of science to the study of structures and processes that we can observe and measure directly or indirectly. • The dependence on observations that people can confirm demystifies nature and distinguishes science from belief in the supernatural. © 2013 Pearson Education, Inc. Discovery Science • Verifiable observations and measurements are the data of discovery science. – In biology, discovery science enables us to describe life at its many levels, from ecosystems down to cells and molecules. © 2013 Pearson Education, Inc. Discovery Science • Jane Goodall studied the behavior and interaction among chimpanzees in the jungle • She made observations that helped explain the social structure among the groups. © 2013 Pearson Education, Inc. Figure 1.14a Discovery Science • She kept a detailed journal that documented her observations. © 2013 Pearson Education, Inc. Figure 1.14b Discovery Science • Discovery science – can stimulate us to ask questions and seek explanations and – uses a process of inquiry called the scientific method, consisting of a series of steps that provide a loose guideline for scientific investigations. © 2013 Pearson Education, Inc. Hypothesis-Driven Science • Most modern scientific investigations can be described as hypothesis-driven science. – A hypothesis is a tentative answer to a question— an explanation on trial. It is a guess as to the answer to a problem. – Although we don’t think of it in those terms, we use hypotheses in solving everyday problems, like figuring out why a TV remote fails. © 2013 Pearson Education, Inc. Hypothesis-Driven Science • Once a hypothesis is formed, an investigator can use logic to test it. – A hypothesis is tested by performing an experiment to see whether results are as predicted. – This deductive reasoning takes the form of “If…then” logic. © 2013 Pearson Education, Inc. Figure 1.15-1 Observation The remote doesn’t work. Question What’s wrong? Hypothesis The batteries are dead. Prediction With new batteries, it will work. Figure 1.15-2 Observation The remote doesn’t work. Question What’s wrong? Hypothesis The batteries are dead. Prediction With new batteries, it will work. Experiment Replace batteries. Experiment supports hypothesis; make more predictions and test. Figure 1.15-3 Observation The remote doesn’t work. Question What’s wrong? Revise. Experiment does not support hypothesis. Hypothesis The batteries are dead. Prediction With new batteries, it will work. Experiment Replace batteries. Experiment supports hypothesis; make more predictions and test. The Process of Science: Are Trans Fats Bad for You? • One way to better understand how the process of science can be applied to real-world problems is to examine a case study, an in-depth examination of an actual investigation. © 2013 Pearson Education, Inc. The Process of Science: Are Trans Fats Bad for You? • Dietary fat comes in different forms. • Trans fats are a non-natural form produced through manufacturing processes called hydrogenation. • Trans fats – add texture, – increase shelf life, and – are inexpensive to prepare. © 2013 Pearson Education, Inc. The Process of Science: Are Trans Fats Bad for You? • A study of 120,000 female nurses found that a diet with high levels of trans fats nearly doubled the risk of heart disease. © 2013 Pearson Education, Inc. The Process of Science: Are Trans Fats Bad for You? • A hypothesis-driven study published in 2004 – started with the observation that human body fat retains traces of consumed dietary fat, – asked the question, Would the adipose tissue of heart attack patients be different from a similar group of healthy patients?, and – formed the hypothesis that healthy patients’ body fat would contain less trans fats than the body fat in heart attack victims. © 2013 Pearson Education, Inc. The Process of Science: Are Trans Fats Bad for You? • The researchers set up an experiment to determine the amounts of fat in the adipose tissue of 79 patients who had experienced a heart attack. • They compared these patients to the data for 167 patients who had not experienced a heart attack. • This is an example of a controlled experiment, in which the control and experimental groups differ only in one variable—the occurrence of a heart attack. © 2013 Pearson Education, Inc. The Process of Science: Are Trans Fats Bad for You? • The results showed significantly higher levels of trans fats in the bodies of the heart attack patients. • You would do well to read nutrition labels and avoid trans fats as much as possible in your own diet. © 2013 Pearson Education, Inc. Trans fats in adipose tissue (g trans fat per 100 g total fat) Figure 1.16 2.0 1.77 1.48 1.5 1.0 0.5 0 Heart attack patients Control group Theories in Science • What is a scientific theory, and how is it different from a hypothesis? – A scientific theory is much broader in scope than a hypothesis. – Theories only become widely accepted in science if they are supported by an accumulation of extensive and varied evidence. © 2013 Pearson Education, Inc. Theories in Science • Scientific theories are not the only way of “knowing nature.” • Science, religion, and art are very different ways of trying to make sense of nature. © 2013 Pearson Education, Inc. The Culture of Science • Scientists build on what has been learned from earlier research. – They pay close attention to contemporary scientists working on the same problem. • Cooperation and competition characterize the scientific culture. – Scientists check the conclusions of others by attempting to repeat experiments. – Scientists are generally skeptics. © 2013 Pearson Education, Inc. The Culture of Science • Science has two key features that distinguish it from other forms of inquiry. Science – depends on observations and measurements that others can verify and – requires that ideas (hypotheses) are testable by experiments that others can repeat. © 2013 Pearson Education, Inc. Science, Technology, and Society • Science and technology are interdependent. – New technologies advance science. – Scientific discoveries lead to new technologies. – For example, the discovery of the structure of DNA about 60 years ago led to a variety of DNA technologies. © 2013 Pearson Education, Inc. Science, Technology, and Society – Technology has improved our standard of living in many ways, but it is a double-edged sword. – Technology that keeps people healthier has enabled the human population to double to 7.2 billion in just the past 40 years. – The environmental consequences of this population growth may be devastating. © 2013 Pearson Education, Inc. Evolution Connection: Evolution in Our Everyday Lives • Antibiotics are drugs that help cure bacterial infections. • When an antibiotic is taken, most bacteria are typically killed. • Those bacteria most naturally resistant to the drug can still survive. • Those few resistant bacteria can soon multiply and become the norm and not the exception. © 2013 Pearson Education, Inc. Evolution Connection: Evolution in Our Everyday Lives • The evolution of antibiotic-resistant bacteria is a huge problem in public health. • Antibiotics are being used more selectively. • Many farmers are reducing the use of antibiotics in animal feed. © 2013 Pearson Education, Inc. Evolution Connection: Evolution in Our Everyday Lives • It is important to note that the adaptation of bacteria to an environment containing an antibiotic does not mean that the drug created the antibiotic resistance. • Instead, the environment screened the heritable variations that already existed among the existing bacteria. © 2013 Pearson Education, Inc.