Chapter 1 The Science of Biology

1. Chapter 1The Science of Biology

2. How Scientist WorkScientific Method • 1. Asking a question • 2. Forming a hypothesis • 3. Setting –up a controlled experiment • 4. Recording & Analyzing Results • 5. Drawing a conclusion • Evaluate hypothesis – support or reject • 6. Publishing & Repeating Investigations

4. Controlled Experiments • _________________________ • Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or CONTROLLED. • _____________________ • The variable that is deliberately changed • ______________________ • The variable that is observed & that changes in response to the manipulated variable.

5. Spontaneous Generation • Ex. People would write recipes for living things. • Francisco Redi tested this hypothesis w/ the meat & fly experiment

6. Figure 1-8 Redi’s Experiment on Spontaneous Generation Section 1-2 OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

7. Figure 1-10 Spallanzani’s Experiment Section 1-2 Gravy is boiled. Flask is open. Gravy is teeming with microorganisms. Flask is sealed. Gravy is free of microorganisms. Gravy is boiled.

8. Biogenesis • __________________________________________________________________________________ • Early scientists debated Spontaneous generation & Biogenesis • Until Louis Pasteur • Experiment with flasks of straight and curved necks & bacteria entering these flasks demonstrated that life comes from life

9. Figure 1-11 Pasteur’s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

10. Figure 1-11 Pasteur’s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

11. Figure 1-11 Pasteur’s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

12. Figure 1-11 Pasteur’s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

13. When are experiments not possible? • _______________________________________________________________________ • ____________________________________________________________________________________________________________

14. Theory • ____________________________________________________________________________________________________________

15. Video 1 Video 1 It’s Alive!, Part 1

16. Characteristics of Living things • 1. Made up of cells • 2. Reproduce • ________________________ • Two cells from different parents unite to produce the 1st cell of the new organism. • ________________________ • The new organism has a single parent • 3. Universal Genetic code • _________

17. 4. Grow & develop • 5. Obtain & use energy • ________________ • The building up or breaking down of materials • 6. Respond to their environment • __________________ • Signal which an organism to. • Ex. Light or temperature • ___________________ • Maintaining a constant internal condition • 7. Change over time • ________________

18. Video 2 Video 2 It’s Alive!, Part 2

19. Figure 1-21 Levels of Organization continued Section 1-3 Organism Individual living thing Bison Tissues, organs, and organ systems Groups of Cells Nervous system Brain Nervous tissue Smallest functional unit of life Cells Nerve cell Groups of atoms; smallest unit of most chemical compounds Molecules DNA Water

20. Figure 1-21 Levels of Organization Section 1-3 Biosphere The part of Earth that contains all ecosystems Biosphere Ecosystem Community and its nonliving surroundings Hawk, snake, bison, prairie dog, grass, stream, rocks, air Community Populations that live together in a defined area Hawk, snake, bison, prairie dog, grass Population Group of organisms of one type that live in the same area Bison herd

21. Microscopes • Light microscopes 1000x • ______________________________________________________________________________ • Electron microscopes • Produce magnified images by focusing beams of electrons. (can’t use living specimens) • ______________________________________ • ______________________________________

22. Laboratory Techniques • Cell culture • _____________________________________________________________________________________________________________________ • Cell fractionation • _______________________________________