Chapter 1The Science of Biology

1-1 What is Science?

The goal of science- is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions.

• “Science”- from Latin verb “to know”

Scientific thinking

Observation- the process of gathering information about events or processes in a careful, orderly way

Data- Information collected from observationQuantitative- how much? numbersQualitative- how?

• Inference- logical interpretation based on prior knowledge or experience

• Hypothesis-proposed scientific explanation for a set of observations

• Must be testable

Science is an ongoing process

Constant testing and reevaluationQuestions that science can answer and cannot answer

“how” vs “why” questions

Science focuses on discovering natural laws

Correlation does not imply causation

• Late 19th cent- craniologists- measured women’s heads, determined they were smaller than the heads of men, and therefore they must be less intelligent

• The more ice cream is sold, the higher the number of people that drown

• Fewer pirates cause global warming• More bald people wear hats- therefore hats must

cause baldness

1-2 How Scientists Work

• Spontaneous generation- Belief that animals come from non-living things

• Maggots found on meat• Mice were found on grain• Beetles found on cow dung

1668 Francesco Redi- disproved Spontaneous Generation

proposed that small fly eggs were being laid on meat

• Laid gauze over meat to prevent flies from accessing it, also had meat without gauze which produced flies

• Mid 1700s John Needham- heated gravy to destroy small organisms and later found they had come back alive

• Lazzaro Spallanzani- heated gravy longer to thoroughly kill small organisms and then closed the lid of the flask. There were no new organisms.

• 1864 Louis Pasteur- had an open flask with a long curved neck. No animals grew- disproved that air was a necessary “life force” for spontaneous generation.

• Pasteur- also developed the first vaccine against anthrax

• Theory- well tested explanation that unifies a broad range of observations (write out definition)

• Theories are revised and changed over time as new information is discovered

1-3 Studying LifeCharacteristics of Living Things1. Living things are made up of units called cells• Cell Theory- cells come from other cells, cells is the smallest unit of life• Cells compose uni-cellular and multi-cellular organisms2. Reproduce• Sexual reproduction- two cells from different parents unite to produce

the first cells of the new organism• Asexual reproduction- new organism is derived from one parent. Ex:

single celled organism splits into two, or a multicellular organisms splits off a bud- like a hydra

3. Based on a universal genetic code• DNA- deoxyribonucleic acid

4. Grow and develop5. Obtain and use materials and energy

– Metabolism- combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes

6. Respond to their environment– Stimulus- a signal to which an organism responds

7. Maintain a stable internal environment– Homeostasis- maintain a balance. Ex: body temperature, blood

oxygenation, water balance8. Taken as a group, living things change over time

Evolution- animals can change over time

• Levels of organization:molecules, cells, groups of cells, organism,

population, community, ecosystem, biosphere

1-4 Tools and procedures

• Metric system, adopted by France in 1791• SI = Le Système International d’Unités• International System• Length= meters• Mass= grams• Volume= liter , 1L= 1000cm3 • Temperature= 0°C freezing point, 100°C boiling point

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