1 Chapter 01: Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Exploring Life and Science

2 Points to ponder What is biology? What characterizes life? How do we classify life? Where do humans fit into the big picture? How do we study science? Where is scientific information published and what should you be aware of?

3 What characteristics are shared by living organisms? Organized Use materials and energy from the environment Maintain a relatively constant internal environment (homeostasis) Respond to internal and external stimuli Reproduce and grow Have an evolutionary history through which organisms change over time 1.1 The Characteristics of Life

4 Natural Selection

5 How are living things organized? 1.1 The Characteristics of Life Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. nervous systemshoot system leaf photosynthetic tissue plant cell brain nervous tissue neuron Biosphere Regions of the Earth’s crust, waters, and atmosphere inhabited by living things Ecosystem A community plus the physical environment Community Interacting populations in a particular area Population Organisms of the same species in a particular area Organism An individual; complex individuals contain organ systems Organ System Composed of several organs working together Organ Composed of tissues functioning together for a specific task Tissue A group of cells with a common structure and function Cell The structural and functional unit of all living things Molecule Union of two or more atoms of the same or different elements Atom Smallest unit of an element composed of electrons, protons, and neutrons Figure 1.2 Levels of biological organization.

6 Diversity of Living Things

7 How Do We Classify Organisms? Taxonomy: According to their characteristics Three Domain Classification system (trunk) Five (or Six)-kingdom classification system (branches) Possible characteristics –Presence or absence of a nucleus –Number of cells –Type of metabolism

8 Domains and Kingdoms common ancestor (first cells) EUKARYA common ancestor BACTERIA ARCHAEA Protists Plants Fungi Animals Billions of Years Ago (BYA) domains kingdoms 3 Domains

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10 Domain Eukarya; Kingdom Protista Paramecium, a unicellular protozoan Algae, protozoans, slime molds, and water molds Complex single cell (sometimes filament colonies, or even multicellular Absorb, photosynthesize, or ingest food 1 µm Domain Eukarya; Kingdom Fungi Molds, mushrooms, yeasts, and ringworms Mostly multicellular filaments with specialized, complex cells Absorb food Cantharellula, a club fungi Domain Eukarya; Kingdom Plantae Passiflora, passion flower, a flowering plant Certain algae, mosses, ferns, conifers, and flowering plants Multicellular, usually with specialized tissues, containing complex cells Photosynthesize food E.coli, a bacterium Domain Bacteria Prokaryotic cells of various shapes Adaptations to all environments Absorb, photosynthesize, or chemosynthesize food Unique chemical characteristics Methanosarcina mazei, an archaeon Prokaryotic cells of various shapes Adaptations to extreme environments Absorb or Chemosynthesize food Unique chemical characteristics Domain Archaea Vulpes, a red fox Sponges, worms, insects, fishes, frogs, turtles, birds, and mammals Multi cellular with specialized tissues containing complex cells Ingest food Domain Eukarya; Kingdom Animalia (protist):© Michael Abby/Visuals Unlimited; (fungi): © Ingram Publishing RF; (animal): © Corbis ; (plant): © Pat Pendarvis; (Archaea): © Ralph Robinson/Visuals Unlimited; (Bacteria): © A.B. Dowsett/SPL/Photo Researchers, Inc. 1.6 µm 1.5 µm

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13 How do we classify humans? HumanHouse cat DomainEukaryaEukarya KingdomAnimaliaAnimalia PhylumChordataChordata ClassMammaliaMammalia OrderPrimatesCarnivora FamilyHominidae Felidae GenusHomoFelis Speciessapiensdomesticus 1.2 Humans Are Related to Other Animals

14 What distinguishes humans? Brains Bipedal Language Tool use We modify our environment 1.2 Humans Are Related to Other Animals

15 What do we know about science? Science is a way of knowing about the natural world. Science and scientists should be objective. objective = subjective = Scientific conclusions aren’t “set in stone” Science is studied using the scientific method. 1.3 Science as a Process

16 Scientific theories in biology 1.3 Science as a Process

17 The Scientific Method 1.3 Science as a Process The results are analyzed, and the hypothesis is supported or rejected. Many experiments and observations support a theory. The hypothesis is tested by experiment or further observations. Input from various sources is used to formulate a testable statement. New observations are made, and previous data are studied. Hypothesis Observation Experiment / Observations Conclusion Scientific Theory Figure 1.8 The scientific method.

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19 Observations: Many patients had a particular bacterium near their ulcers. Hypothesis: Helicobacter pylori is the cause of gastritis and ulcers. How the cause of ulcers was discovered: The scientific method in action! 1.3 Science as a Process

20 Experiment/observations: 1 st – H. pylori was isolated and grown from ulcer patients. 2 nd – Humans swallowing a H. pylori solution developed inflammation in their stomachs. Conclusion: H. pylori was the cause of most ulcers and can be cured by antibiotics. How the cause of ulcers was discovered: The scientific method in action 1.3 Science as a Process

21 A controlled study Variables Experimental variable is the factor that is purposely changed or manipulated. All other variables need to remain constant. Groups Test group is a group of subjects that are exposed to the experimental variable. Control group is a group for comparison that is not exposed to the experimental variable. 1.3 Science as a Process

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Science as a Process A controlled study in action Figure 1.10 Design of a scientific study. a. c. d. Subjects were divided into three groups. Perform Experiment: Groups were treated the same except as noted. Large number of subjects were selected. State Hypothesis: Antibiotic B is a better treatment for ulcers than antibiotic A. Collect Data: Each subject was examined for the presence of ulcers. Test group 2: received antibiotic B Control group: received placebo Test group 1: received antibiotic A a (both): © blickwinkel/Alamy; c: © Phanie/Photo Researchers Control Group Test Group 1 Test Group Effectiveness of Treatment (%) Conclusion: Hypothesis is supported: Antibiotic B is a better treatment for ulcers than antibiotic A. Treatment of Ulcers by Antibiotics b.

24 Reading about scientific information Scientific journals are considered the best source of information but can be difficult for the average person to understand. Often we read secondary sources and must be wary of information taken out of context. Be careful of information on the Internet! Use reliable sources such as URLs with.edu,.gov and.org. 1.3 Science as a Process

25 What should you look for when you read about science? Beware of anecdotal data (stories). Understand methodology and results. Does the data justify the conclusions inferred by the scientists? Be able to read a graph. Have some understanding of statistics. 1.4 Making Sense of a Scientific Study

26 Reading a graph What information does this line graph convey? 1.4 Making Sense of a Scientific Study Figure 1.11 The presentation of scientific data. standard error Week 1Week 2Week 3Week 4 x-axis y-axis Blood Choletsterol (mg/dL) 175 Data Variation in Blood Cholesterol Levels

27 Does science have social responsibilities? Science is a way of acquiring knowledge about the natural world through a systematic process separating it from ethics, religion, and aesthetics. 1.5 Science and Social Responsibility

28 Does science have social responsibilities? Technology is the application of scientific knowledge to human interests. -Biotechnology (genetically modified bacteria and genetically modified crops) -Gene technology (cloning of humans or gene therapy to modify inheritance) -Use of stem cells from embryos (embryonic stem cells) 1.5 Science and Social Responsibility

29 Everyone is responsible! The Western world believes that science and technology improve our lives. All citizens should assume responsibility. You make the future happen! Everyone needs to be involved in making value judgments about the proper use of technology. You will learn more about all of these as you prgress through this course. Consider your opinions. 1.5 Science and Social Responsibility