Introduction: Biology Today PDF

# Introduction: Biology Today ## Why Biology Matters * If you've ever wondered what an unusual or especially beautiful animal is called, you're curious about taxonomy. * One of the primary missions of the Mars rover is to search for signs of life. * Although you may not realize it, you use the sci...

# Introduction: Biology Today ## Why Biology Matters * If you've ever wondered what an unusual or especially beautiful animal is called, you're curious about taxonomy. * One of the primary missions of the Mars rover is to search for signs of life. * Although you may not realize it, you use the scientific method every day. ## An Innate Passion for Life * Do you like biology? If you have a pet, are concerned with fitness or healthy eating, have ever visited a zoo or an aquarium for fun, taken a nature hike, or gathered shells on the beach, you like biology! * Most of us have an inherent interest in life, an inborn curiosity about the natural world that leads us to study animals and plants and their habitats. * We wrote *Essential Biology* to help you harness your innate enthusiasm for life. You'll develop an understanding of the discipline of biology, one that can be applied to your own life and to the society in which you live. * We believe that such a biological perspective is essential for any educated person. Whatever your reasons for taking this course, you'll discover that exploring life is relevant and important to you. ## The Scientific Study of Life ### Define Biology Biology is the scientific study of life. ### The Process of Science * **The scientific study of life** implies there are distinct nonscientific ways to research life. * **Science is based on inquiry**, a search for information, explanations, and answers to specific questions. * Two main scientific approaches: * **Discovery science**, mostly about describing nature, observes and measures structures and processes. * **Hypothesis-driven science** mostly about explaining nature. #### Discovery Science * Scientists seek natural causes for natural phenomena. * Data is the information on which scientific inquiry is based. * Science can neither prove nor disprove supernatural beliefs. #### Hypothesis-Driven Science * Observations of discovery science motivate us to ask questions and seek explanations. * The scientific method is a formal process of inquiry that includes a series of steps: 1. **Observation:** an event, a pattern, or a set of facts. 2. **Question:** asking why or how this happened. 3. **Hypothesis:** a tentative explanation for a set of observations. 4. **Prediction:** a statement that forecasts what would happen if the hypothesis is correct. 5. **Experiment:** a test of the prediction. 6. **Results:** data from the experiment. 7. **Revise/Repeat:** the hypothesis is revised or new hypotheses are made if results do not support the hypothesis. ## Theories in Science * A scientific theory is a comprehensive explanation supported by abundant evidence. * Theories are broader than a hypothesis and generate new testable hypotheses. ## The Nature of Life * Biology attempts to answer the basic question: What is life? * Biologists define life by what living things do, focusing on properties shared by all living things. ### The Properties of Life * Properties generally considered to be alive if they are present simultaneously: * **Order:** a complex but ordered organization. * **Regulation:** adjusting internal environment to maintain appropriate limits. * **Growth and development:** information by DNA controls the pattern of growth and development in all organisms. * **Energy processing:** organisms take in energy and use it for life's activities. * **Response to the environment:** organisms respond to environmental stimuli. * **Reproduction:** organisms reproduce their own kind. * **Evolution:** populations of organisms change over time. ### Grouping Species: The Basic Concept * Taxonomy is the branch of biology that names and classifies species into a hierarchy of broader and broader groups. ### The Three Domains of Life * On the broadest level, biologists divide the diversity of life into three domains: * Bacteria * Archaea * Eukarya * **Prokaryotic cells** are relatively small and simple cells that lack a nucleus or other compartments bounded by internal membranes. * **Bacteria** * **Archaea** * **Eukaryotic cells** are relatively large and complex cells that contain a nucleus and other membrane-enclosed compartments. * **Eukarya**, which further includes: * **Kingdom Plantae** (Plants) * **Kingdom Fungi** (Fungi) * **Kingdom Animalia** (Animals) * **Protists** (diverse group of organisms with multiple kingdoms) ## Major Themes in Biology * There are broad themes running throughout biology. * These overarching principles unify all aspects of biology, from the microscopic world of cells to the global environment. ### Evolution * **Evolution:** a lineage of organisms that accumulate change over time. * **Natural Selection:** the process by which individuals with heritable traits best suited for the local environment are more likely to survive and leave the greatest number of healthy offspring. * **Adaptation:** the accumulation of variations in a population over time. ### Structure/Function * The shape (structure) of something correlates to what the object does ( its function). ### Information Flow * **Information Flow:** involves receiving, transmitting, and using information at all levels of biological organization. * **Genes:** hereditary units of information consisting of DNA sequences. * **Genomics:** the study of whole genomes. ### Energy Transformations * Movement, growth, reproduction, and cellular activities require energy. * **Energy Flow:** energy enters an ecosystem as light and exits as heat. * **Matter Cycling:** matter is recycled within an ecosystem. ### Interconnections within Biological Systems * **Biological systems** are interconnected, from the microscopic scale of molecules and cells to the global scale of the biosphere. * **Organelles:** functional components of cells * **Tissues:** a group of similar cells performing a specific function. * **Organs:** composed of two or more tissues, * **Organ Systems:** composed of two or more organs. * **Organisms:** an individual living thing. * **Populations:** interacting individuals of one species. * **Communities:** all organisms in an ecosystem. * **Ecosystems:** all living organisms in a particular area and all the nonliving components of the environment. * **Biosphere:** all life and all the places where life exists. ## Chapter Review ### The Scientific Study of Life * Biology is the scientific study of life and it distinguishes scientific investigations from other ways of thinking. ### The Process of Science * The scientific means of investigating life quality as biology. ### Discovery Science * Describing the natural world with verifiable data is the Hallmark of discovery science. ### Hypothesis-Driven Science A scientist formulates a hypothesis (tentative explanation) to account for observations of the natural world. The hypothesis may then be tested via the steps of the scientific method. ### Theories in Science * A theory is a broad and comprehensive statement about the world that is supported by the accumulation of great deal of verifiable evidence. ### The Nature of Life * All life displays a common set of characteristics: * Order * Regulations * Growth and development * Energy processing * Response to the environment * Reproduction * Evolution