Chapter 1 The Science of Biology

1. Chapter 1The Science of Biology

2. 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”

3. Scientific thinking Observation- the process of gathering information about events or processes in a careful, orderly way Data- Information collected from observation Quantitative- how much? numbers Qualitative- how?

4. Inference- logical interpretation based on prior knowledge or experience

5. Hypothesis-proposed scientific explanation for a set of observations • Must be testable

6. Science is an ongoing process Constant testing and reevaluation Questions that science can answer and cannot answer “how” vs “why” questions Science focuses on discovering natural laws

7. 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

8. 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

9. 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

10. Mid 1700s John Needham- heated gravy to destroy small organisms and later found they had come back alive • LazzaroSpallanzani- heated gravy longer to thoroughly kill small organisms and then closed the lid of the flask. There were no new organisms.

11. 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

12. 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

13. 1-3 Studying Life Characteristics of Living Things 1. 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 organisms 2. 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

14. 4. Grow and develop 5. 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 balance 8. Taken as a group, living things change over time Evolution- animals can change over time

15. Levels of organization: molecules, cells, groups of cells, organism, population, community, ecosystem, biosphere

16. 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