What does science mean to you? The Science of Biology What does science mean to you? Investigate Explain Make predictions

Thinking Like a Scientist Observations – gathering information and recording data quantitative – involves characteristics that can be measured qualitative - involves characteristics that are not measured Interpret data – inferences may be made Propose a hypothesis – possible explanation for an observed phenomenon or possible answer to a scientific question; must be testable

The experimental design

The experimental design State the problem – statement or question based on an observation Formulate a hypothesis – possible explanation of observed phenomenon Set up a controlled experiment where only one variable is changed independent variable – what you are changing dependent variable – what you are measuring

The experimental design Record and Analyze Results – using notebooks, drawings, computers Drawing a Conclusion – use the evidence from the experiment to support or refute the hypothesis Publish results – allows other scientists to repeat the experiment in order to verify the results http://www.classzone.com/cz/books/bio_09/resources/htmls/animated_biology/unit1/bio_ch01_0029_ab_expdes.html (The Experimental Design)

Does the experimental design work for everything? How would you observe elephant behavior? Field study – observations made without human interference Would it be ethical to observe the effect of LSD on elephants? Lysergic acid diethylamide, a synthetic crystalline compound, that is a potent hallucinogenic drug

Can science answer all questions? Is this painting beautiful?

What is the difference between a hypothesis, a theory, and a scientific law A theory is well tested explanation that unifies a broad range of observations (Fig. 1-13) A scientific law is true and is usually associated with a mathematical equation (Charles’ Law - Assuming that pressure remains constant, the volume and absolute temperature of a certain quantity of a gas are directly proportional. V/T=K)

Characteristics of life Nerve Cell Striated Muscle

Characteristics of life All living things are made up of cells which are the smallest units of life (Fig. 1-15) unicellular – single celled multicellular – many celled All living things reproduce sexual – two parents produce offspring that are genetically unique asexual – one parent, offspring are genetically identical

Characteristics of life

Characteristics of life

Characteristics of life http://www.youtube.com/watch?v=7pR7TNzJ_pA (amoeba – a single celled organism) http://www.youtube.com/watch?v=12OmszObAkM (hydra – a multicellular organism) http://www.arkive.org/brown-hydra/hydra-oligactis/video-09.html (budding in hydra - asexual reproduction)

Characteristics of life

Characteristics of life Based on a universal genetic code DNA – is the molecule that carries this code and determines the inherited traits of all organisms Growth and Development growth is an increase in the size and/or number of cells development is when cells become specialized or differentiate http://www.youtube.com/watch?v=W-FO8tZQGfk&feature=related (seed growth)

Characteristics of life

Characteristics of life Obtain and Use Materials and Energy Metabolism – all the chemical reactions within an organism Respiration – process that releases energy by breaking down food molecules aerobic – oxygen is required anaerobic – oxygen is not required

Characteristics of life Obtain and Use Materials and Energy Plants convert solar energy into chemical energy in the process of photosynthesis Animals obtain their energy by eating plants or other animals.

Characteristics of life

Characteristics of life Respond to changes in the environment seed germinates when watered some animals migrate when temperatures change Maintain a stable internal environment which is known as Homeostasis

Characteristics of life

Characteristics of life

Characteristics of life Groups of living things evolve over time. Changes are the result of characteristics being selected for or selected against.

Levels of Organization (Fig. 1-21)

Tools & Procedures of Scientists International System of Units

Tools & Procedures of Scientists International System of Units

Tools & Procedures of Scientists Analyzing Data (See Fig. 1-24)

Tools & Procedures of Scientists Light microscope

Tools & Procedures of Scientists Light microscope

Tools & Procedures of Scientists Light microscope – any device that uses light to produce an enlarge view of an object magnification – ratio of image size to object size (ocular x objective) resolution – ability of microscope to show two points that are close together separately (sharpness of image) compound microscope – 2 lenses, prepared specimens must be thin enough for light to pass through (see Appendix D) stereomicroscope – study external or surface structure of specimens

Tools & Procedures of Scientists Electron Microscope

Tools & Procedures of Scientists transmission electron – electron beams hit specimen and pass through, are absorbed, or scattered

Tools & Procedures of Scientists scanning electron – electron beam is focused and passed back & forth over a surface; produces 3D images

http://www.classzone.com/cz/books/bio_09/resources/htmls/animated_biology/unit1/bio_ch01_0021_ab_cells.html This site shows how various cells look when viewed through different types of microscopes.

Tools & Procedures of Scientists Laboratory Techniques cell cultures – maintain living cells or tissue in a culture medium outside of the body

Tools & Procedures of Scientists Laboratory Techniques cell fractionation – cells are broken into pieces and the different cell parts are separated at various speeds and durations to isolate components of different sizes, densities and shapes

Tools & Procedures of Scientists Laboratory Techniques centrifugation – liquid separation based on densities

Tools & Procedures of Scientists Laboratory Techniques electrophoresis – uses electric current to separate substances

Tools & Procedures of Scientists Laboratory Techniques computers – collect, store, analyze data, generate images of body tissue