Concepts in Biology Enger Et Al. Dr. Michael Gillespie Doctor of Chiropractic Beginner’s Mind “In the beginner’s mind there are many possibilities, but in the experts there are few. If your mind is empty, it is always ready for anything; it is open to everything.” – Shunryu Suzuki Biology Biology is the science that deals with life. Science is a process used to solve problems or develop an understanding of natural events. This process is known as the scientific method. Scientific Method The scientific method is a way of gaining information (facts) about the world by forming possible solutions to questions. Rigorous testing is employed to determine if the proposed solutions are supported. Basic Assumptions in Science There are specific causes for events observed in the natural world. The causes for events in nature can be identified. There are general rules or patterns that describe what happens in nature. Basic Assumptions in Science Repeated events probably have the same cause. What one person observes can be observed by others. The same fundamental rules apply, regardless of when or where they occur. Cause and Effect Some events are correlated (happen together). Some events have a cause and effect relationship (an event is a direct result result of a previous event). Components of the Scientific Method Observation Hypotheses Openness to new information and ideas Willingness to submit ones ideas to the scrutiny of others Observation Observations are made using our senses or an extension of our senses. Observations are careful, thoughtful recognition of an event. Questioning and Exploration Optimal questions lend themselves to experimentation. Explore other sources of knowledge relevant to the question. Hypothesis A hypothesis is a statement that provides a possible answer to a question or an explanation for an observation that can be tested. Characteristics of a Good Hypothesis Logical Account for all relevant information Predict future events Testable Use the simplest hypothesis with the fewest assumptions Einstein “Make everything as simple as possible, but not simpler.” Testing a Hypothesis A good hypothesis is testable. It can be either supported or disproved. If a hypothesis cannot be disproved, confidence in it increases. New information can encourage scientists to reformulate an hypothesis. Methods for Testing a Hypothesis Collect relevant information. Make additional observations. Devise an experiment. Experiment An experiment is a re-creation of an event or occurrence in a manner that allows the scientist to support or disprove a hypothesis. Variables Variables are individual factors that help determine the outcome of an event. Controlled Experiment A controlled experiment is one in which only one variable is present. Two groups: Control group – no manipulation of the variable. Experimental group – a group in which one variable is manipulated. Variables Independent variable – is manipulated in the experiment by the scientist. Dependent variable – will change as a result of manipulation of the independent variable. There should be only one independent variable in an experiment. Be careful not to introduce additional variables into the experiment. Development of Theories and Laws If new evidence consistently and repeatedly supports the original hypothesis and other related hypotheses, we begin to see patterns emerge. Scientific theories and laws come into existence. Inductive Reasoning The process of developing general principles from the examination of many specific facts is known as inductive reasoning or induction. Deductive Reasoning The process of using general principles to predict the specific facts of a situation is called deductive reasoning or deduction. Scientific Theory A theory is a widely accepted, plausible, general statement about fundamental concepts in science that explain why things happen. A theory is a very broad statement , which is the result of years of observation, questioning, experimentation, and data analysis. Theory Vs. Hypothesis A hypothesis provides a possible explanation for a specific question; whereas a theory is a broad concept that shapes how scientists look at the world and how they frame their hypotheses. Scientific Law A scientific law is a uniform or constant fact of nature that describes what happens in nature. Theory Vs. Law Theory Law Describes why things Describes what happens happen in nature Examined repeatedly Examined repeatedly Independently verified Independently verified Excellent predictors of Excellent predictors of how nature behaves how nature behaves Theoretical And Applied Science Theoretical science helps us understand the structure and function of things in nature. Applied science has practical value. It has applications that change the way we live. Science And Nonscience The difference between a scientist and a non-scientist is lies in the manner in which assumptions are tested. A scientist continually challenges and tests principles and assumptions to determine cause and effect relationships. Pseudoscience Pseudoscience is a deceptive practice that uses the appearance or language of science to convince, confuse, or mislead people into thinking that something has scientific validity. What Is Life? Living things have the ability to interact with their surroundings. Living things can manipulate energy and matter. Energy is the ability to do work. Matter is anything that has mass and takes up space. Characteristics Of Life Metabolic processes. Generative processes. Responsive processes. Control processes. Unique structural organization. Metabolism Metabolism is the sum of all the chemical processes that occur in the body. Catabolism – The breaking down of complex chemical substances into simpler ones. Anabolism – The building up of complex chemical substances from simpler ones. Generative Processes Generative processes are activities that result in an increase in the size of an organism (growth) or an increase in the number of individuals in a population (reproduction). Growth Growth is an increase in body size that results from an increase in the size of existing cells, the number of cells, or both. A tissue can increase in size due to an increase in the amount of material between cells (i.e. bone tissue). Reproduction Reproduction is the formation of new cells for tissue growth, repair, or replacement. The formation of new cells for the production of a new individual organism (i.e. through fertilization of an ovum by a sperm cell). Two Types Of Reproduction Sexual reproduction – two individuals each contribute sex cells, which leads to the creation of a new, unique organism. Asexual reproduction – an organism makes identical copies of itself. Responsive Processes Responsiveness is the body’s ability to detect and respond to changes in it’s internal and external environment. Control Processes Control processes are mechanisms that ensure an organism will carry out all metabolic activities in the proper sequence (coordination) and at the proper rate (regulation). Levels Of Coordination Coordination occurs at the metabolic level. Chemical reactions are regulated in the human body by enzymes. Coordination also occurs at the organism level. Movement Motion of the whole body. Motion of individual organs. Motion of single cells. Motion of structures inside cells. Differentiation Differentiation is a process a cell undergoes to develop from an unspecialized to a specialized state. Each type of cell has a specialized state and function. Stem cells divide and give rise to progeny that undergo differentiation. Regulation Regulation involves altering the rate of processes. The process of maintaining a constant internal environment is called homeostasis. Unique Structural Organization The unique structural organization of living things can be seen at the molecular, cellular, and organism levels. Cells are the fundamental structural units of all living things. An organism is any living thing that is capable of functioning independently. Levels Of Body Organization Chemical level Cellular level Tissue level Organ level System level Organism Chemical Level Atoms – smallest units of matter that participate in chemical reactions. Molecules – two or more atoms joined together. Cellular Level Molecules combine to form cells. Cells are the basic structural and functional units of an organism. Cells are the smallest living units in the human body. Cells are made up of organelles. Tissues Tissues are groups of cells and the materials surrounding them that work together to perform a particular function. 4 basic tissue types in the human body: Epithelial tissue. Connective tissue. Muscle tissue. Nervous tissue. Organs Organs are composed of two or more tissues that work together to perform specific functions. They usually have recognizable shapes. System Level A system consists of related organs that have a common function. Sometimes an organ is part of more than one system. There are eleven systems in the human body. Organ Systems Integumentary Cardiovascular Muscular Respiratory Skeletal Digestive Nervous Urinary Endocrine Reproductive Lymphatic and immune Integumentary System Components – skin, hair, nails, sweat glands, oil glands. Functions – protects the body; Helps regulate body temperature; Eliminates wastes; Makes vitamin D; Detects sensations such as touch, pain, warmth, and cold. Muscular System Components – muscles, tendons. Functions – produces body movements, such as walking; Stabilizes body position (posture); Generates heat. Skeletal System Components – bones, joints, associated cartilages. Functions – supports and protects the body; Aids body movements; Houses cells that produce blood cells; Stores minerals and lipids. Nervous System Components – brain, spinal cord, nerves, special sense organs (I.E. Eyes and ear). Functions – generates action potentials (nerve impulses) to regulate body activities; Detects changes in the body’s internal and external environments, interprets these changes, and responds causing muscular contractions or glandular secretions. Endocrine System Components – hormone producing glands and hormone producing cells. Functions – regulates body activities by releasing hormones (chemical messengers) transported in blood from an endocrine gland to a target organ. Lymphatic and Immune System Components – lymphatic fluid and vessels; Spleen, thymus, lymph nodes, tonsils. Functions – returns proteins and fluids to blood; Carries lipids from gastrointestinal tract to blood; Includes structures that generate lymphocytes (protect against disease-causing organisms). Cardiovascular System Components – blood, heart, and blood vessels. Functions – heart pumps blood through vessels; Blood carries oxygen and nutrients to cells and carbon dioxide and wastes away from cells; Regulates acid-base balance, temperature, and water content of body fluids; Components defend against disease. Respiratory System Components – lungs, air passageways such as the pharynx (throat), larynx (voice box), trachea (windpipe), and bronchial tubes. Functions – transfers oxygen from inhaled air to blood and carbon-dioxide from blood to exhaled air; Regulates acid-base balance, air flowing out through vocal cords produces sounds. Digestive System Components – mouth, esophagus, stomach, small and large intestines, and anus (organs of GI tract); Salivary glands, liver, gallbladder, pancreas (accessory organs). Functions – physical and chemical breakdown of food; Absorbs nutrients, eliminates solid wastes. Urinary System Components – kidneys, ureters, urinary bladder, urethra. Functions – produces, stores, and eliminates urine; Eliminates wastes; Regulates volume and chemical composition of blood; Maintains acid-base balance; Maintains mineral balance; Helps regulate production of red blood cells. Reproductive Systems Components – gonads (testes in males, ovaries in females), associated organs (uterine tubes, uterus, and vagina in females and epididymis, ductus deferens, and penis in males). Functions – gonads produce gametes (sperm or oocytes); Gonads release hormones. Further Levels Of Organization Population – a group of individual organisms of a particular kind. Community – populations of different kinds of organisms that interact with one another in a particular place. Ecosystem – communities (groups of populations) that interact with the physical world in a particular place. Biosphere – the worldwide ecosystem.