The Science of Biology Chapter 1 Mrs. Meggs Fall 2011

What is Science? The goal of science is to investigate and understand nature, to explain events in nature, and to use those explanations to make useful predictions.

Biology= The Study of Life Bio- (Life) -logy (Study of)

Observation Scientific thinking usually begins with observation– the process of gathering info about events or processes in a careful and orderly way. Scientific thinking usually begins with observation– the process of gathering info about events or processes in a careful and orderly way. –Generally uses the senses.

Data - information gathered from observations. There are 2 types of data: 1. Quantitative- expressed as numbers found by counting or measuring. 2. Qualitative- descriptive and involve characteristics that can’t be counted. 2. Qualitative- descriptive and involve characteristics that can’t be counted.

Scientists use data to make inferences – a logical interpretation of data or evidence collected.

Scientific Method 1. Define the problem 2. Form a hypothesis 3. Test the hypothesis (controlled experiments) 4. Analyze data 5. Draw conclusions and Record results

Defining Scientific Method Hypothesis – possible explanation of a problem Hypothesis – possible explanation of a problem –It must be testable –Stated as “If ……then……” format

Controlled Experiment An experiment in which a single variable is changed in one set up but not in the other. An experiment in which a single variable is changed in one set up but not in the other. Control – the standard in which all conditions are kept the same Control – the standard in which all conditions are kept the same Independent Variable – the condition that is changed. Independent Variable – the condition that is changed. –(Manipulated variable, x-axis) Dependent Variable – the measurable condition that RESULTS from changing the Independent variable. Dependent Variable – the measurable condition that RESULTS from changing the Independent variable. –(Responding variable, y-axis)

Replication Repeating investigations: a key idea in science is that experimental results can be repeated--- if the results change each time, then the experiment is not considered valid. Repeating investigations: a key idea in science is that experimental results can be repeated--- if the results change each time, then the experiment is not considered valid.

Scientific Theories  A theory attempts to explain everything about a phenomenon including it’s cause. Examples: Examples: –The Big Bang Theory –Evolution

Scientific Law A statement that describes some aspect of a phenomenon that is TRUE A statement that describes some aspect of a phenomenon that is TRUE Does not explain how or why Does not explain how or why –Example: The law of gravity

Studying Life- Branches of Biology Botany – study of plants Botany – study of plants Zoology – study of animals Zoology – study of animals Ecology – study of interactions between living things and their environment Ecology – study of interactions between living things and their environment Genetics – study of heredity Genetics – study of heredity Microbiology – study of microorganisms Microbiology – study of microorganisms Evolution – study of living things changing over time Evolution – study of living things changing over time Biochemistry – study of organic molecules Biochemistry – study of organic molecules

Spontaneous Generation Pasteur- tested the hypothesis of spontaneous generation. –He showed that living things come from other living things.

8 Characteristics of Living Things Composed of Cells Have a genetic code Reproduce Respond to their environment Obtain and use materials and energy Grow and develop Change over time- “Evolution” Maintain homeostasis

Made up of Cells Cells – smallest unit of life Cells – smallest unit of life 1. Unicellular organisms- consist of only a single cell 2. Multicellular organisms- contain more than one cell - The human body has over 85 different types of cells.

Reproduce 2 types of reproduction: 1. Sexual Reproduction- cells from two different parents unite to form the first cell of a new organism 2. Asexual Reproduction- new organism has a single parent (ex.- hydra)

Genetic Code Directions for inheritance come from DNA Directions for inheritance come from DNA Grow and Develop Life cycles involve growth and development

Obtain and Use Materials and Energy 1. Metabolism: chemical reactions through which organisms break down materials 2. Photosynthesis: the way plants, most algae, and some bacteria obtain their energy- process of converting light energy into stored energy. 3. Decomposers: obtain materials from remains of dead organisms

Respond to the environment Organisms respond to stimuli from the environment – (ex: light, temperature, food) Organisms respond to stimuli from the environment – (ex: light, temperature, food) Ex- hunger Maintain internal balance Homeostasis-process by which organisms maintain a stable internal balance– to stay the same. Homeostasis-process by which organisms maintain a stable internal balance– to stay the same. Ex. – body temperature

Change over time Evolution- a change in an organism over time Evolution- a change in an organism over time

Levels of Organization in Biology (See graphic on pg. 21) - From smallest to largest and least complex to most complex 1. Molecules 2. Cells 3. Groups of Cells 4. Organism 5. Population 6. Community 7. Ecosystem 8. Biosphere

Measurements Scientists use a universal system of measurement called Systeme International (SI) or the Metric System Scientists use a universal system of measurement called Systeme International (SI) or the Metric System Importance of a common system – allows scientists all over the world to communicate with each other and share data. Importance of a common system – allows scientists all over the world to communicate with each other and share data.

Units of Measurement- SI Units DistanceMeter VolumeLiter Temperature Kelvin– Degree Celsius is commonly used in Science MassGram

Common Prefixes Kilo X (thousand) Hecto 100 X (hundred) Deca 10 X (ten) UNIT Deci 0. 1 X (tenth) Centi 0.01 X (hundredth Milli X (thousandth)

Sample Problems 25.8 g = __________ kg 25.8 g = __________ kg 1000 g = _________ kg 1000 g = _________ kg 45.9 cm = ________ m 45.9 cm = ________ m 100 m = __________ mm 100 m = __________ mm 75.2 mL = ________ L 75.2 mL = ________ L 10 dm = __________ m 10 dm = __________ m 27 L = ____________ kL 27 L = ____________ kL

Sample Problems 25.8 g =.0258 kg 25.8 g =.0258 kg 1000 g = 1 kg 1000 g = 1 kg 45.9 cm =.459 m 45.9 cm =.459 m 100 m = mm 100 m = mm 75.2 mL =.0752 L 75.2 mL =.0752 L 10 dm = 1.0 m 10 dm = 1.0 m 27 L =.027 kL 27 L =.027 kL

Analyzing Data Scientists often use graphs to analzye data: Scientists often use graphs to analzye data: Line graphs, pie charts, bar graphs

Line graphs When graphing the data from an experiment-- The graph should have a title The graph should be drawn to scale Independent variable (manipulated variable)- goes on the X axis Dependent variable (resulting variable) –goes on the Y axis

Tools of the Trade: The Microscope Allows scientists to see objects that would never be seen with the unaided eye Allows scientists to see objects that would never be seen with the unaided eye

Three Types of Microscopes Simple Microscope – Consists of only a single lens Simple Microscope – Consists of only a single lens Light Microscope – consists of two lens. One lens magnifies the object and the other magnifies image. Light Microscope – consists of two lens. One lens magnifies the object and the other magnifies image. Electron Microscope – electron beams are passed through the specimen and the image is projected onto a monitor. Better resolution and magnification. Two types – TEM and SEM Electron Microscope – electron beams are passed through the specimen and the image is projected onto a monitor. Better resolution and magnification. Two types – TEM and SEM

Lab Techniques 1. Cell cultures- single cell in a nutrient solution– then that cell produces many cells 2. Cell fractionation- cell is separated into different cell parts