Chapter 1 The Science of Biology CP Biology

Chapter 1: The Science of Biology • 1. 1: What is Science? • 1. 2: Science in Context • 1. 3: Studying Life – Measurement – Safety

1. 1 The Science of Biology

What is Science? • An organized way of studying things and finding answers

The Scientific Method • 1. ) State the Problem • 2. ) Gather Data • 3. ) Form a Hypothesis – Hypothesis: Educated Guess • 4. ) Perform an Experiment – Control – Variable • 5. ) Analyze the Data – Sources of error • 6. ) Draw Conclusions

The Scientific Method

Parts of an Experiment • Control: the standard to which the outcome of a test is compared • Variable: something in the experiment that you are testing that can change – Independent variable: (manipulated) deliberately changed – Dependent variable: (responding variable) changes in response to the independent variable

1. 2: Science in Context

What scientific attitudes help generate new ideas? • • • Curiosity Skepticism Open-mindedness Creativity Arise from practical problems Technology – discovery in one field of science may lead to new technologies • Peer review –sharing knowledge and ideas

Scientific Theory • An explanation of things or events based on scientific knowledge that is a result of many observations and experiments • Well tested explanation • DOES NOT change unless new evidence becomes available

Scientific Law • A statement about how things work in nature that seems to be true all the time • Less likely to change than scientific theories

Science and Society • Science, ethics, and morality – Pure science does NOT include ethical or moral viewpoints • Avoiding Bias – Bias: a particular preference or point of view that is personal rather than scientific

1. 3 Studying Life

Characteristics of Living Things • 1. ) are made up of cells • 2. ) based on the universal genetic code (DNA) • 3. ) maintain a stable environment (homeostasis) • 4. ) Respond to their environment • 5. ) Use energy (metabolism) • 6. ) Grow and develop • 7. ) Reproduce • 8. ) Evolve

1. ) Living things are made up of cells • Any living thing is called an Organism. • Cells are the smallest unit of an organism that carries on the functions of life. – 2 Types of Organisms • Single cell: made of just one • Multicellular: made of many

2. ) Living things are based on the universal genetic code (DNA) • DNA: deoxyribonucleic acid – Located in the nucleus of cells – Contains genetic information – Passed on to offspring

3. ) Living things maintain a stable environment • All organisms need to keep their internal environment relatively stable, even when external conditions change – homeostasis

4. )Living things respond to their environment • Stimulus: – Anything that causes a change in an organism – Examples: • Light • Temperature • Sounds • Response: – A reaction to a stimulus

Example of Stimulus/Response A cat hears a can of food being opened (assumes it’s for him) and usually runs to the kitchen

5. ) Living things use energy

6. ) Living things grow and develop

7. ) Living things reproduce • Sexual Reproduction: – Cells from 2 parents unite to form the first cell of a new organism – The offspring is genetically DIFFERENT • Asexual Reproduction: – A single organism produces offspring identical to itself • Example: bacteria

Sexual vs. Asexual Reproduction Paramecium dividing (Asexual Reproduction)

8. ) Living things evolve • Over generations, groups of organisms evolve, or change over time. • Evolutionary change links all forms of life to a common origin more than 3. 5 billion years ago. • Evidence is found in all aspects of living things, fossil organisms, physical freatures to DNA.

What do living things need? • A place to live • Raw materials – Examples: • Water • Food

Central Themes of Biology • Cellular basis of life • Information and heredity • Matter and energy • Growth, development, and reproduction • Homeostasis • • Evolution Structure and function Unity and diversity Interdependence in nature • Science as a way of knowing

Field of Biology • Global ecology – An ecologist studies the environment • Biotechnology – Ex: plant biologist analyzes genetically modified rice plants • Building tree of life – Ex: a paleontologist studies signs of ancient life • Ecology & evolution of infectious diseases – Ex: a wildlife biologist studies a group of wild gelada baboons • Genomics and molecular biology – a molecular biologist analyzes a DNA sequence

Scientific Measurements

SI Units of Measurement • • • Length – meter ruler (m) Mass – scale (g) Volume – solids: • regular shaped objects – • irregular shaped objects – – length x width x height (cm 3) water displacement liquids – graduated cylinder (m. L)

Metric Prefixes King Henry Died Drinking Chocolate Milk kilo (k) hecto deka UNIT * (h) (dk/da) deci (d) centi (c) milli (m) 1/1000 100 10 1 1/10 km hm dkm m dm cm mm kg hg dkg g dg cg mg kl hl dkl L dl cl ml

Practice Problems Prefix Conversions • 45. 3 g = • 0. 345 m. L= 0. 00000345 h. L • 89 m = 89000 mm • 45000 dl = 4. 5 kl • 2. 5 kg = 250000 cg • 7 dkm = 700 dm 45300 mg

Density • Formula: D = m v • Units: – solids: g/cm 3 – liquids: g/m. L • Density of water: 1 g/m. L – if an object/liquid has a density less than that of water, it will float; – if it has a density greater than that of water, it will sink • 1 m. L = 1 cm 3

Practice Problems Density • Example 1: A solution has a mass of 2. 5 g and a volume of 37 m. L. What is the density? m = 2. 5 g D = m/v v = 37 ml D=x D = 2. 5 37 = 0. 068 g/m. L • Example 2: A solid object has a mass of 79. 35 g and a volume of 12. 4 m. L. What is the density of the object? m = 79. 35 D = m/v x = 79. 35 v = 12. 4 m. L 12. 4 = 6. 4 g/cm 3 D=x

Lab Safety

Lab Safety RULES • DO NOT joke around while doing labs. • Stay at your lab table during the entire lab. • Follow all directions and precautions CAREFULLY!!! • Tie long hair back. • Roll up loose or hanging sleeves. • Wear gloves (when applicable). • Wear goggles (when applicable). • Clean up your table and all materials. • Wash your hands before leaving the lab.

Lab Safety Symbols