Asking a Question

1. Asking a Question • For years….. • ____________________! • Maggots on meat • Mold on bread • Fruit Flies on bananas • How do new living things come into being?

2. Forming a Hypothesis • ______________________– life could arise from non-living matter. • Beetles from dung • Mice from grain • All created by _________________________

3. Forming a Hypothesis • Spontaneous Generation is a hypothesis! • 1668 Francesco Redi • Italian physician • Proposed a hypothesis for appearance of maggots • Observed organisms (maggots) appeared on meat a few days after flies. • Thought….. “_______________?”

4. Forming a Hypothesis • Proposed a new _________________: • Flies produce maggots, not meat • Next step: • TEST _____________________!

5. Setting up a Controlled Experiment • The factors in an experiment that can change are the ______________________. • ________________________________________ __________________________________________. • 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 _____________. • _____________________________________

6. Setting up a Controlled Experiment • Variable that is deliberately changed = _____________________(manipulated variable) • Variable that is observed and that changes in response to the manipulated variable is called the = __________________(responding variable) • MILK LAB • What is the independent variable? • ________________________________ • What was dependent variable? • __________________________

7. Setting up a Controlled Experiment • Testing for maggots • How would you use meat to see if maggots are spontaneously generated from meat? • ______________________________________ • Work with your lab partner to create an experiment. • ____________________________________

8. Setting up a Controlled Experiment • What are you going to control (___________variables)? • ___________________ • ___________________ • ___________________ • ___________________ • ___________________

9. Setting up a Controlled Experiment • What is your independent variable (manipulated variable)? • ___________________________ • PAGE 9 EXPERIMENT

10. Recording and Analyzing Results Archimedes 287 BC to 211 BC • Notebooks • Journals Leonardo da Vinci1452 to 1519

11. Galileo Galilei   1564-1642 Historical Use As long as people have been investigating natural phenomena, they have been keeping records of what they do. Why? It would appear that keeping records allows the investigator to go back and review original thoughts or to modify their thoughts. The science notebook is an integral part of the investigative process.

12. Drawing a Conclusion • Use data from an experiment to evaluate the hypothesis and draw a valid _____________. • Use evidence to determine if hypothesis was _____________or ___________________. • Redi’s results supported or refuted his hypothesis? • _______________________ • HUGE ISSUE! • _______________________________________!

13. 1862 Pasteur & Spontaneous Generation • Curved neck flask & broth • Air was ___________to the source of life • Redi’s experiment did not allow air in • Pasteur believed __________________ were responsible for growth -Curved flask let air in, but micro- organisms could not enter. *________________________! Broke neck = full of microorganisms! *FINALLY DISPROVED _________________________ ______________________________!

14. How a Theory Develops • As evidence from numerous investigations builds up, a particular _______________may become so well supported, scientists consider it a theory. • In science, the word ___________applies to a well tested explanation that unifies a broad range of explanations.

15. Studying Life – 1.3 • Objectives • Describe some characteristics of living things • Explain how life can be studied at different levels

16. Studying Life • The word biology means the study of life • http://www.youtube.com/watch?v=vX07j9SDFcc • _______________is the science that seeks to understand the living world • A biologist is someone who uses ______________ methods to study living things

17. 8 Characteristics of Living Things • Living things share these characteristics: • _______________________ • Reproduce • Based on a genetic code • ______________________ • Obtain and use materials & energy • Respond to their ________________ • Maintain a stable internal environment • _______________________________

18. Made Up of Cells • Living things are made up of small, self-contained units called, __________. • _____________– collection of living _________ enclosed by a barrier that separates the cell from its surroundings. • ______________are the __________units of an organism considered to be alive. • Very complex and highly ____________!

19. Made Up of Cells • _____________organisms – single celled • _______________– many celled • Human body has at least 85 different types of cells!

20. Reproduction • All organisms produce new organisms through a process called ______________. • ______________Reproduction– the cells from two different parents ________to produce the first cell of the new organism. • Maple trees • Birds • Humans

21. Reproduction 2. _______________Reproduction – new organism has a single parent. ______-_________organism divides in half to form two new organisms.

22. Based on a Genetic Code • Offspring usually resemble their parents • ______________Reproduction – offspring __________from their parents

23. Based on a Genetic Code • _______Reproduction – offspring and parents have the _________traits

24. Based on a Genetic Code • Directions for inherit traits is one of the greatest achievements of modern biology. • ________ • Deoxyribonucleic acid • Determines directions for _____________

25. Growth and Development • All living things grow and develop • From ________fertilized egg cell  ____ death • Need for materials and energy • __________________ • The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out life processes.

26. Response to the Environment • A stimulus is a signal to which an organism responds. • If you are hungry, your stomach growls • Plant roots grown in the direction of gravity • _________of light & temperature are examples of factors that alter living things _______________.

27. Maintaining an Internal Balance • _______________– involves internal feedback mechanisms • Hot = sweat to cool you off • Increased heart rate, increase need for oxygen, increase breathing rate

28. Figure 1-21 • PAGE 21

29. Tools & Procedures 1.4 • Objectives • Describe the measurement system most scientists use • Explain how light microscopes and electron microscopes are similar and different • Describe two common laboratory techniques • Explain why it is important to work safely in biology

30. A Common Measurement System • Most scientists use the metric system when collecting data and performing experiments. • SI system; International System of Units • FIGURE 1-23 page 24

31. At what time of day is the rate of water released by leaves equal to the rate of water absorbed by roots? • FIGURE 1-24 page 25

32. Microscopes • Microscopes that produce magnified images of structures that are too small to see with the unaided eye. • ______________microscopes – magnify images by focusing visible light rays. • ______________microscopes – magnify by focusing beams of electrons.

33. ______Microscope • Compound light microscopes allow light to pass through the specimen and uses 2 lenses to form an image. • ___________________ • ___________________ • ___________________ • ___________________

34. _________________Microscope • More detailed than _______microscopes • Transmission Electron Microscopes (TEM’s) • Shine beam of electrons through a thin specimen • Scanning Electron Microscopes (SEM’s) • _____________________ • All specimens are dead

35. Page 27 Analyzing Data • Work with your partner to complete the 5 questions. • Turn them in with your name, date, and class period on all papers.