1. Introduction to Biology Lecture 1 Fall 2008

2. What is Biology? Biology – The scientific study of life What is science? What is life? 1

3. Life What is life?? Fig. 1.3 2

4. Themes in Biology 1. Cells are an organism’s basic units of structure and function The lowest level of structure that can perform all activities required for life 3 Fig. 1.8

5. Themes in Biology 2. Continuity of life is based on heritable information in the form of DNA 4 Fig. 1.10

6. Themes in Biology 3. Structure and Function are correlated at all levels of biological organization 5 See Fig. 1.4

7. Themes in Biology 4. Emergent properties The whole is greater than the sum of its parts New properties emerge with each step upward in the hierarchy of life 6

8. Themes in Biology Reductionism & Systems Biology Fig. 1.12 Fig. 1.10 7

9. Themes in Biology 5. Organisms interact with their environments, exchanging matter and energy Fig. 1.5 8

10. Themes in Biology 6.Feedback mechanisms regulate biological systems Negative & Positive feedback Fig. 40.8 Fig. 40.16 9

11. Themes in Biology 6. Evolution is the theme that unifies all biology “Nothing in biology makes sense except in the light of evolution” - Theodosius Dobzhansky 10 See Fig. 1.22

12. Themes in Biology Diversity and Unity – the dual nature of life All life unified by basic properties Vast diversity of biological forms Globally - ~1.8 million species ~10,000 birds ~ 4629 mammals ~ 8240 reptiles ~ 900,000 insects (named) ~ 300,000 vascular plants ~ 20,000 fish Washington State ~ 466 birds ~ 139 mammals ~ 25 reptiles ~ 3200 plants ~ 211 fish (Puget sound) 11

13. Fig. 1.14 Themes in Biology Diversity and Unity See Fig. 1.15 12

14. The Theory of Evolution by Natural Selection Evolution: - a genetically based change in the characteristics of a population over time. Explains the diversity and similarity of organisms; how organisms have come to be adapted to a wide range of environments. Process = Natural selection 13

15. The Theory of Evolution by Natural Selection 1.Individuals within a population vary in traits. 2.At least some of the variation must be heritable so it can be passed onto offspring (DNA). 3.In every generation, more offspring are produced than can survive (overproduction and competition). 4.Unequal reproductive success - Survival and reproduction of individuals is not random. Outcome of process: Population’s characteristics will change over time = Evolution will occur. 14

16. The Theory of Evolution by Natural Selection Fig. 1.20 15

17. Artificial Selection 16

18. Why study biology?? 17

19. What is Science? A way of knowing, based on inquiry A search for an understanding of the natural world Attempts to discover order in nature and to use that knowledge to make predictions about what should happen in nature Exploring and explaining the world 18

20. What is Science? Science seeks natural causes for natural phenomena Discovery Science Descriptive science Based on observations & measurements Inductive reasoning – generalization that summarizes a large number of observations “bottom-up 19

21. What is Science? Science seeks natural causes for natural phenomena Hypothesis-driven Science Asking questions and seeking explanations Scientific Method Deductive reasoning – moves from general to more specific “top-down” 20

22. The Scientific Method Make observations Formulate a hypothesis Test hypothesis: Experimental design and data collection Draw conclusions Analyze & interpret data Prompts questions Makes a testable prediction New observations or controlled experiments Supports or refutes hypothesis? Publish results Scientific hypothesis: A proposed explanation; An educated guess that attempts to explain an observed pattern. Prediction: A statement of what you should be able to measure or observe in nature if the hypothesis is correct. 21

23. The Scientific Method Skepticism Peer Review Reproducibility 22

24. Scientific Theory Common usage – Theory: (2) Abstract reasoning, speculation. (4) An assumption based on limited information or knowledge, a conjecture. The American Heritage Dictionary, 3rd Ed. 1992 Scientific Theory: Well-tested and widely accepted scientific hypothesis 23

25. Scientific Uncertainty Quantitative Data Precise and easily compared Good benchmark for measuring change Statistics Important in both planning and evaluating scientific studies Sample size, number of replications important Probability Measure of how likely something is High degree of scientific certain, 95% probability 24

26. Dry Falls & the Missoula Floods J. Harlen Bretz 1923 - Geology of channeled scablands in eastern WA due to flooding on a massive sale J.K.Barndt, 2004 1940 – evidence of a huge lake in Montana that had emptied rapidly 1950 - Aerial photography – Bretz’s work finally accepted 25

27. Regrowth of insulin producing beta cells Scientific American, Dec 2006 2001 Dr. Denise Foustman published work on regrowth of insulin producing beta cells to help cure diabetes “Consensus” science believed this was not possible 2006 – 3 groups reported in Science that Dr. Foustman’s work had been reproduced

28. The scientific method – a case study Observations: Two snakes look alike Predators rarely attack eastern coral snake Eastern coral snake is poisonous, scarlet king snake is not Fig. 1.25 26

29. The scientific method – a case study Question: Does the mimicry protect the Scarlet king snake? 27 Fig. 1.25

30. The scientific method – a case study Hypothesis: The king snake mimicry of the coral snake helps protect it from predators in areas where the two species ranges overlaps Prediction: Predators will attack snakes with rings of bright red, yellow and black less frequently than plain snakes 28 Fig. 1.25

31. The scientific method – a case study Experiment: Create two types of artificial snakes –Colored –Plain Record how many attacks occur on each type Results: Support hypothesis Conclusion: Mimicry reduces the amount of predation on the Scarlet king snake where the two ranges overlap 29 Fig. 1.27