Week 1 + 2 - Humans in World of Biology PDF

Chapter 1 Humans in the World of Biology Lecture Presentation by Tonya Bates, UNC Charlotte © 2017 Pearson Education,...

Chapter 1 Humans in the World of Biology Lecture Presentation by Tonya Bates, UNC Charlotte © 2017 Pearson Education, Inc.  Humans in the World of Biology Outline:  Basic Characteristics of All Living Things  Evolution: A Unifying Theme in Biology  Levels of Biological Organization  Scientific Method  Critical Thinking to Evaluate Scientific Claims © 2017 Pearson Education, Inc.  1.2 What is Science? Science is a body of knowledge; a collection of unified insights about nature, the evidence for which is an array of facts. Why Study Science? An understanding of science can help you take better care of your health, be a wiser consumer, and become a better- informed citizen. Science can also be used to improve the world around you. Science as a Body of Knowledge Scientific Theory  A theory is an explanation of a natural phenomenon supported by many observations and the same results over and over, that explains some aspect of nature. Example – The Theory of Gravity  The unified insights of science are known as theories. Science as a Body of Knowledge  Science can also be defined as a way of learning; a process of coming to understand the natural world through observation and the testing of hypotheses. Science as a Body of Knowledge Science as a Body of Knowledge  Science works through the scientific method, in which an observation leads to the formulation of a question about the natural world.  Science is a tentative, testable explanation that has not been proven true.  The hypothesis may be tested through observation or through a series of experiments, as aided by statistical procedures. Science as Process  An example of hypothesis testing is Louis Pasteur’s experiment regarding the spontaneous generation of life Science as Process Scientific method at work: Pasteur tests “spontaneous generation” Observation growth of sterile flask new material in broth sterile broth When you start with a sterile... a growth of new living material flask of sterile meat broth... generally appears in the broth. Question: What is the source of the living material? Hypothesis: Hypothesis 1 Hypothesis 2 The living material is derived from nonliving The living material is derived from material (spontaneous generation). living material outside of the flask. Pasteur’s experiments: remove trap dust trapped sterile flask in neck of flask Particle growth trap no growth sterile broth growth tip flask to mix trapped dust into broth Conclusion: No growth appears in the broth unless dust is admitted from outside. Reject “spontaneous generation” hypothesis. Figure 1.5  01.02 Which of the following statements best describes the nature of a scientific hypothesis? 1. A hypothesis is an idea that is widely accepted as a description of objective reality by a majority of scientists. 2. A hypothesis must stand alone, and not be based on prior knowledge. 3. A hypothesis must be testable through experimentation, observation, or mathematical demonstration. 4. A hypothesis is the same as an observation. 5. For any scientific question there is only one hypothesis tested. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Definition of Hypothesis  A hypothesis is a possible explanation for an observation  A hypothesis Must be tested to determine its validity. Is often tested in many different ways. Allows for predictions to be made.  Iterative Hypotheses can be changed and refined with new data. 11 Using Experiments to Test Hypotheses  Experiment Tests the hypothesis. Must be carefully designed to test only one variable at a time. Consists of a test experiment and a control experiment. 12 Using Predictions Hypotheses should make predictions. Predictions provide a way to test the validity of hypotheses. Hypothesis must be rejected if the experiment produces results inconsistent with the predictions. The more experimentally supported predictions a hypothesis makes, the more valid the hypothesis. 13  A Hypothesis-Driven Experiment  SCIENTIFIC THINKING  Question: What is the source of contamination that occurs in a flask of nutrient broth left exposed to the air?  Germ Hypothesis: Preexisting microorganisms present in the air contaminate nutrient broth.  Prediction: Sterilized broth will remain sterile if microorganisms are prevented from entering flask.  Spontaneous Generation Hypothesis: Living organisms will spontaneously generate from nonliving organic molecules in broth.  Prediction: Organisms will spontaneously generate from organic molecules in broth after sterilization.  Test: Use swan-necked flasks to prevent entry of microorganisms. To ensure that broth can still support life, break swan-neck after sterilization.  Result: No growth occurs in sterile swan-necked flasks. When the neck is broken o, and the broth is exposed to air, growth occurs.  Conclusion: Growth in broth is of preexisting microorganisms.  Figure 1.4  Access the text alternative for slide images. 14 Philosophical Approaches to Science  Reductionism.  To break a complex process down to its simpler parts.  Systems biology.  Focus on emergent properties that can’t be understood by looking at simpler parts. 15 Models in Science Way to organize thought Parts provided by reductionist approach Model shows how parts fit together Models can suggest experiments to test how components work together 16 Scientific Theory  A body of interconnected concepts  Supported by much experimental evidence and scientific reasoning  Expresses ideas of which we are most certain  Compare to general meaning of theory  Implies a lack of knowledge or an educated guess. 17  1.4 Scientific Method  Science is an approach to answering questions through systematic documentation and experimentation  The scientific method is this systematic logical approach to gathering information and reaching conclusions © 2017 Pearson Education, Inc.  1.4 Scientific Method—Step-by-Step 1. Make careful observations and ask questions about those observations 2. Formulate a testable hypothesis that provides an explanation about the observations and answers to the questions 3. Provide a prediction and then an experiment with two groups, control and experimental, to determine whether the hypothesis is supported Both groups should be treated identically except for one independent variable, the factor whose effect the experiment is designed to reveal © 2017 Pearson Education, Inc.  1.4 Scientific Method—Step-by-Step 4. Reach a conclusion based on the results of the experiment, and review statistical significance 5. Develop new questions and additional experiments to further refine the conclusions 6. Over time, after many experiments have repeatedly confirmed related hypotheses, a theory may be developed that offers a broad-ranging explanation for some aspect of the physical universe © 2017 Pearson Education, Inc.  Figure 1.4 Make new predictions and test them. Results support hypothesis Form Experiment/ Observation a Hypothesis Prediction Further Results Conclusion Question observation Results do not Revise hypothesis, make new predictions, support hypothesis and test them with new experiments. © 2017 Pearson Education, Inc.  Figure 1.5 Question: Does eating oatmeal lower blood cholesterol? Hypothesis: Eating oatmeal lowers blood cholesterol levels Prediction: If oatmeal consumption lowers blood cholesterol levels, then a person’s cholesterol level will be lowered by eating a bowl of oatmeal a day for 6 weeks. Perform experiment Experimental Control Group: Group: Consumes 1 oz of Consumes 1 oz of oatmeal per day farina per day © 2017 Pearson Education, Inc. Science Is Hypothesis-Driven  Scientists use a systematic approach to gain understanding of the natural world.  Access the text alternative for slide images. 23  Figure 1.7 5.75 Blood level LDL cholesterol mmol/L farina 2 oz 5.50 1 oz 3 oz 5.25 5.00 4.75 4.50 4.25 Start 1 2 3 4 5 6 7 8 9 10 11 12 Weeks © 2017 Pearson Education, Inc.  1.4 Scientific Method © 2017 Pearson Education, Inc.  1.4 Scientific Method  Inductive reasoning involves the accumulation of facts through observation until finally there are enough facts to draw a conclusion or develop a testable hypothesis © 2017 Pearson Education, Inc.  1.4 Scientific Method  Deductive reasoning involves making a general statement, often in the format of an “if-then” statement, then drawing more specific conclusions from it In deductive reasoning, a series of observations leads to a general statement that often sets the stage for further experimentation © 2017 Pearson Education, Inc.  1.4 Scientific Method  Experiments that deal with medicines or other materials used by humans are first tested on laboratory animals, typically rodents  If these tests go well, then the first clinical trials begin using humans, all of whom must provide informed consent to participate in the studies © 2017 Pearson Education, Inc.  1.4 Scientific Method  Clinical trials consist of several experimental groups that receive different dosages of the drug and a control group that receives a placebo, a substance made to look like the drug being tested  A double-blind study occurs when neither researchers nor participants know which group is receiving the treatment  Epidemiological studies look for patterns that occur in large populations © 2017 Pearson Education, Inc. © 2017 Pearson Education, Inc. © 2017 Pearson Education, Inc.  Table 1.1 © 2017 Pearson Education, Inc. 1.3 The Nature of Biology The Nature of Biology  Biology is the study of life. Characteristics of Living Things  Life is defined by a group of Eight Characteristics possessed by living things. Organisms Organisms :an individual animal, plant, or single celled life form.  An ORGANISM is a living thing.  All organisms : share characteristics that separate them from non-living things. All organisms share EIGHT characteristics that make them alive.  A living (biotic) organism must have all EIGHT !  1.1 Basic Characteristics of All Living Things  All living things contain the molecules of life and include four macromolecules: Nucleic acids Proteins Carbohydrates Lipids © 2017 Pearson Education, Inc. 8 Characteristics of Living Things 1. Made up of one or more cells 2. Display organization 3. Grow and develop 4. Reproduce 5. Respond to stimuli 6. Require and use energy 7. Maintain Homeostasis 8. Move  All living things… are made up of cells. 1) Made up of one or more cells  Are composed of one or more cells  A cell is the smallest “unit of life”  CELL: the smallest basic unit of structure and organization of all living organisms  Some organisms have only a single cell… others have many – the human body contains over 100 trillion cells That’s 100,000,000,000,000!! All living things… display organization. 2) Display organization  Arranged in an orderly way  Cells Tissues Organs Organ Systems Organism  Are highly organized compared to inanimate objects. All living things… grow and develop 3. Grow and develop  Growth: addition of mass to an organism  Development: the process that occurs in an organism's life that results in a more complex organism. All living things… reproduce. 4. Reproduce Basically, this means that they can make more of their own kind!  SPECIES: A group of organisms that mate together and have fertile offspring.  Asexual Reproduction – when a single parent doubles its contents and splits in two to create a new organism (ex:bacteria)  Sexual Reproduction – when two different parents unite to produce a new organism (ex:humans) All living things…respond to stimuli. 5. Respond to stimuli  Stimuli: Anything from the environment that causes some sort of reaction.  Such as: Temperature, light, sound, and other factors that cause living things to respond.  Nonliving objects (rocks for instance) do not respond to stimuli! 44  All living things…require and use energy. 6. Require and use energy Used to run the processes of life  Assimilate energy.  Humans (and other animals) get energy from the food we eat  Plants get energy from the sunlight, through a process called photosynthesis All living things are homeostatic 7. Maintain Homeostasis  Homeostasis: is the ability of an organism to maintain relatively constant internal conditions.  An example is temperature regulation in the human body.  All organ systems contribute to homeostasis.  Living things adapt  Adaptations come about through evolution.  Evolution is the process by which a species changes through time. Evolution: Theory that groups of organisms change over time  Occurs over many generations due to selection and adaptation to changing environments. All living things can move 8. All living things can move  Animals move to find food and shelter. Movement can be the difference between life and death.  Plants do not move, but they bend toward sunlight.  All living things also have internal movement of substances (food, water, waste etc.) Life is Hierarchical  Life is organized in a hierarchical manner, ranging in increasing complexity:  From atoms to molecules to organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and the biosphere. Life is Hierarchical atom Molecule organelle cell tissue organ organ system organism population community ecosystem biosphere (hydrogen (water) (nucleus) (neuron) (nervous tissue) (brain) (nervous system) (sea lion) (colony) (giant kelp (southern California (Earth) forest) coast) Figure 1.6 Hierarchical Organization of Living Systems  Living systems show hierarchical organization Cellular level  Atoms, molecules, organelles, cells  Cell is the basic unit of life (that is Cell Theory). Organismal level  Tissues, organs, organ systems 51 Cellular Level Hierarchical Organization  (Organelle): Keith R. Porter/Science Source; (Cell): SPL/Science Source; (Tissue): Ed Reschke;  Access the text alternative for slide images. 52 Organismal Level Hierarchical Organization  (Organism): Russell Illig/Getty Images;  Access the text alternative for slide images. 53 Hierarchical Organization—Additional Levels Populational level  Population, community Ecosystem level Biosphere  Earth is an ecosystem we call the biosphere.  Each level has emergent properties. Result from interaction of components. Cannot be deduced by looking at parts themselves. “Life” is an emergent property. 54 Populational Level Hierarchical Organization  (Population): George Ostertaga/gefotostock/Alamy Stock Photo; (Species): Sander Meertins/iStock/Getty Images; Pictureguy/Shutterstock; (Community): Ryan McGinnis/Alamy Stock Photo; (Ecosystem): Robert and Jean Pollock; (Biosphere): Goddard Space Flight Center/NASA  Access the text alternative for slide images. 55  1.1 Basic Characteristics of All Living Things  All living things are composed of cells Cells are the smallest units of life All cells arise from preexisting cells  Living things grow and are capable of reproduction  Living things use energy and raw materials to carry out metabolism Metabolism refers to all the chemical reactions that occur within the cells of living things © 2017 Pearson Education, Inc.  1.1 Basic Characteristics of All Living Things  All living things Respond to their environment Maintain homeostasis  Homeostasis is the relatively constant and self- correcting internal environment of a living organism © 2017 Pearson Education, Inc.  1.1 Basic Characteristics of All Living Things  Organisms have adaptive traits that allow them to survive and reproduce  Populations will ultimately evolve © 2017 Pearson Education, Inc. Figure 1.2 Domain Bacteria Domain Archaea Domain Eukarya Unicellular Unicellular Eukaryotic cells that contain a membrane-bound nucleus and internal compartments prokaryotic prokaryotic organisms organisms; most live in extreme environments Kingdoms Protists Fungi Plants Animals Protozoans, algae, Molds, mushrooms Mosses, ferns, Invertebrates diatoms seed plants and vertebrates © 2017 Pearson Education, Inc.  1.2 Evolution: A Unifying Theme in Biology  Humans are unique because they Have a relatively large brain Stand upright on two legs Have opposable thumbs © 2017 Pearson Education, Inc.  1.3 Levels of Biological Organization  Atoms are units of matter that cannot be broken down any further  Cells, the smallest units of life, are composed of molecules, the chemical components of cells  Cells may contain organelles that carry out specific functions © 2017 Pearson Education, Inc.  1.3 Levels of Biological Organization  Cells with the same function are grouped into tissues  Two or more tissues working toward the same function are organs  At least two organs working together to perform a function form an organ system  An individual is a single organism made of organ systems © 2017 Pearson Education, Inc.  1.3 Levels of Biological Organization  Many individuals of the same species living together in a common geographical area are called a population  When several populations interact, they form a community  A community and its physical environment are called an ecosystem  All organisms exist within the much larger biosphere, the part of Earth where life is found © 2017 Pearson Education, Inc. Figure 1.3 Atom A unit of matter that cannot be further broken down Molecule The chemical components of cells Organelle A component within the cell that carries out specific functions Cell The smallest unit of life Tissue A group of similar cells that perform the same function Organ A structure with two or more tissues working together to perform a function Organ systems At least two organs working together to perform a function Individual A single organism Population All individuals of the same species in an area Community All the species in an ecosystem that can interact Ecosystem A community and its physical environment Biosphere The part of the earth that supports life © 2017 Pearson Education, Inc.  1.5 Critical Thinking to Evaluate Scientific Claims  Critical-thinking skills are used to analyze information and make wise decisions  It is everyone’s responsibility to ask questions, evaluate data, and make informed decisions  Scientists publish their work in peer-review journals  Not all information found online is relevant, accurate, or even true  Everyone should remain skeptical and evaluate the source of information © 2017 Pearson Education, Inc. Table 1.2 © 2017 Pearson Education, Inc. 1.4 Special Qualities of Biology Special Qualities of Biology Until the early nineteenth century, biology was largely a descriptive science that mainly catalogued and described the Earth’s living things. Biology’s subject matter—the living world—is notable for its complexity and diversity compared to other aspects of the natural world (such as stars and atoms).  Biology’s Chief Unifying Principle Biology’s chief unifying principle is evolution, which can be defined as the gradual modification of populations of living things over time. This modification sometimes results in the development of new species. Evolution provides the means for making sense of the forms and processes seen in living things on Earth today.  Darwin and the Theory of Evolution Example of how a scientist develops a hypothesis and a theory gains acceptance Charles Darwin served as naturalist on a mapping expedition around coastal South America 30 years of observation and study before publishing On the Origin of Species by Means of Natural Selection 72  Voyage of the HMS Beagle https://www.youtube.com/watch?v=JOk_0mUT_JU Huntington Library/Superstock Access the text alternative for slide images. 73  Natural Selection as a Mechanism for Evolution Darwin was not the first to propose evolution – Living things have changed over time. Darwin’s contribution was a mechanism – Natural selection. 74  Darwin Observed Differences in Related Organisms On the Beagle, Darwin saw that characteristics of similar species varied from place to place Galápagos Finches 14 related species differ only slightly. “Descent with modification” or evolution. Access the text alternative for slide images. 75