Bellringer In your composition book, write 1 paragraph (at least 4 sentences) explaining how biology relates to you personally. You may also include illustrations to show the relationship. Remember to keep your entry school appropriate.

Chapter 1: The Study of Life

Introduction to Biology September 12, 2013

What is Biology? Biology = the study of life (bio – life, logos – study)

Main Idea List as many living things as you can in 60 seconds. What do these have in common? What makes them unique? How do we know?

What Do Biologists Do? Study the diversity of life –Jane Goodall = chimpanzees in the wild; chimps also use tools (not just humans) Research disease –Mary-Claire King: chimp genetics; humans & chimps 99% genetically similar –New understanding of diseases Develop technologies –Bionic appendages –Charles Drew – separated blood cells from plasma; safely transport plasma for transfusions during WWII

Improve agriculture –Genetically engineered plants to grow in poor soil or resist insects, fungal infections, frost damage –Improve food production to feed world population Preserve the environment –Prevent extinction

What is Life? Properties of Life: –Made of one or more cells –Displays organization –Grows and develops –Reproduces –Responds to stimuli –Requires energy –Maintains homeostasis –Adaptations evolve over time

All living things are made of one or more cells Cell = highly organized, tiny structure with a thin covering called a membrane Smallest unit of life Smallest organisms are unicellular (single cell) Largest organisms contain millions of cells Picture: Paramecium

Displays Organization Example: Paramecium –single cell –Cell made of molecules & compounds –Molecules & compounds made of atoms

Grow & Develop Growth Increase in mass, size, or add more cells Development Process of natural change that takes place during life of organism

Living Things Reproduce Reproduction = production of offspring Continues life of species, not organism –Species: group of organisms that can breed with one another & produce fertile offspring Not essential characteristic (not necessary for life of individual to continue) Without reproduction the species will become extinct

Responds to Stimuli Response = reaction to a stimulus Stimulus = anything part of internal or external environment that causes a response Organisms must respond to stimuli in order to survive long enough to reproduce

Requires Energy Living things get energy from food Energy fuels life functions Plants & some unicellular organisms use energy from the sun for food & fuel Some unicellular organisms transform energy in chemical compounds to make food Some organisms (animals & fungi) consume food to get energy Most energy is changed into thermal energy and radiated to environment as heat

Maintains Homeostasis All living things must maintain a stable internal environment Homeostasis = maintenance of stable internal conditions in spite of changes in external environment No homeostasis = death

Adaptations Evolve Over Time Adaptation = any inherited characteristic that results from changes to a species over time allow organisms to survive and pass on traits to offspring Drip tip leaves in the rainforest

The Nature of Science

What is Science? Science = a body of knowledge based on the study of the natural world In everything you do Guided by scientific inquiry (the development of explanations) Theory = an explanation of a natural phenomenon supported by many observations and experiments over time Cell theory & theory of evolution Scientific law = describes relationships under certain conditions in nature Laws do not become theories and theories do not become laws

Nature of Science Makes observations and draws conclusions Expand knowledge Challenges accepted theories Questions results Tests claims Undergoes peer review = a process by which procedures and results of an experiment are evaluated by other scientists who are in the same field or who are conducting similar searches

Science in Everyday Life Not limited to laboratory Each of us must be scientifically literate to evaluate all of the information available in media Issues: disease, drugs, global warming, pollution, genetic engineering, cloning, euthanasia, cryonics Involve ethics = a set of moral principles or values

Methods of Science

The Way Things Are… Writing & Reporting Scientific Method Steps in order States findings & describes experiments Conducting Science Scientific Method Steps not always in order Not all steps used/completed Use creativity & curiosity Fix missteps Revise hypotheses Reach dead ends

Ask a Question Observations Hypothesis Collect Data Collect and Analyze Results Report Conclusions Test Again

Ask a Question Scientific inquiry begins with observation = a direct method of gathering information in an orderly way –Using 5 senses Asking questions and processing information from a variety of reliable sources Scientific methods = ways scientists often gather information

Hypothesis A testable explanation of a situation NOT A GUESS!! When supported by data from additional investigations, usually considered valid and accepted by the scientific community If data does not support, hypothesis revised and more investigations are conducted

Collect the Data Experiment = a method of testing a hypothesis in a controlled setting Controlled setting –Control group = used for comparison and to validate data –Experimental group = the group exposed to the factor being tested

Experimental Design –During an experiment, only 1 factor can change at a time –Independent variable (IV) = the tested factor; affects the outcome of the experiment; changed by experimenter Manipulated variable –Dependent variable (DV) = results of experiment; results from or depends on the independent variable Responding variable –Constant = a factor that remains the same during an experiment while the IV & DV changes

Data Gathering –Data = information gathered from observations as scientists test hypotheses Quantitative – numerical data –Time, temperature, length, mass, area, volume, or density Qualitative – descriptions of what our senses detect Investigations –Laboratory (involves manipulating variables) –Field (involves making observations)

Metric System –Units that are powers of 10 –Commonly known as SI = International System of Units developed in 1960 Meter (m) – length Gram (g) – mass Liter (L) – volume Second (s) - time

Step Diagram

Analyze the Data Has my hypothesis been supported? Are more data needed? Are different procedures needed? Often experiments are repeated many times to obtain consistent data Patterns in data are often found that explain the data Table or graph Results could lead to further hypotheses Results are still valued even if hypothesis not supported

Graphing and Organizing Data

Why? Graphing is a way of organizing data to see patterns or trends and to interpret data

Types of Graphs Line Graph –Shows relationships between 2 or more variables Bar Graph –Shows comparisons and frequency distributions Pie Chart –Shows parts of a whole

Graph Set-Up DV (responding variable) IV (manipulated variable)

Steps 1.Determine which variable is IV and DV 2.Determine scale of x and y axis –Make graphs as large as possible, within limits of paper and still include highest data points –Too big – cannot make out graph details –Too small – won’t convey all information on graph 3.Plot data

Reading a Graph Describe graph –Title –X-axis –Y-axis –Units Describe data –Numerical range of data –Kinds of patterns in data Interpret Data –How do patterns in data relate to other things you know?

Report Conclusions Scientific journals Before publication, work is reviewed by peers

Minilab: Manipulate Variables P. 19 in textbook Complete in composition book