Exploring the Significance of Biology in Everyday Life

1. TWIRTEENTH EDITION Enger • Ross • Bailey CHAPTER 1

2. Chapter opener 01

3. 1.1 The Significance of Biology in Your Life

4. Consider how your future will be influenced by how the following questions are ultimately answered： • How can we reduce the probability that new strains of disease-causing bacterial will evolve? • Is DNA testing reliable enough to be admitted as evidence in court cases ? • Why is there an epidemic of obesity in the United States? Can physicians and scientists manipulate our genes in order to control certain disease conditions we have inherited ? • Will the thinning of the ozone layer of the upper atmosphere result in increased incidence of skin cancer ? • Will a vaccine for AIDS be developed in the next 10 years ? • Will new, inexpensive, socially acceptable methods of birth control be developed that can slow world population growth ? • Are human activities really causing the world to get warmer ? • How dose extinction of a species change the ecological situation where it once lived ?

5. Why study biology? • To be an informed citizen. • An understanding of biology is important to address a number of social issues today. • DNA testing • Birth control • Global warming • AIDS

6. Example 1： Human population should be slowed. Killing infants and forced sterilization. • Example 2： Mad Cow Disease. It is important to recognize that science has a role to play but that is does not have the answers to all our problems. (Social and Philosophical Questions)

7. 1.2 Science and Scientific Method • The science that deals with life. • What is science? • A process used to solve problems and understand natural events. • Involves the scientific method.

8. Basic assumptions in science • Scientists approach their work with some basic assumptions • Natural events have specific causes. • Those causes can be identified. • Natural events follow general rules and patterns. • A recurrent natural event has a common cause. • Different people can observe the same natural events. • Natural laws hold true regardless of time and place. • Example: Lightning

9. Scientists look for cause and effect relationships • Events that happen simultaneously are correlated, but • may or may not have a cause and effect relationship. • Example: Autumn and falling leaves • Events have a cause and effect relationship • when one event happens as a direct result of a preceding event. • Example: Lightning causes thunder.

10. The scientific method • A way of gaining information about the world that involves • forming possible solutions to questions. • rigorous testing to determine if the solutions are supported. • continual checking and rechecking to make sure that previous conclusions are still supported. • modification of unsupported conclusions.

11. Components of the scientific method • Observation • Questioning and exploration • Forming and testing hypotheses • Evaluation of new information • Review by peers

12. The scientific method in action

13. Observation, questioning and exploration • An observation is a thoughtful and careful recognition of an event or a fact (see next slide). • The careful observation of a phenomenon leads to a question (see next slide). • How does this happen? • What causes it to occur? • The question must be testable. • Scientists then explore scientific publications to find any information that has been gathered about the question.

14. Figure 1_03

16. Figure 1_04a

17. Figure1_04b

18. Constructing hypotheses • Once the question is asked, scientists propose answers. • These answers are hypothesis. • Hypotheses must: • Be logical • Account for all current information • Be testable • Make the least possible assumptions

19. Testing hypotheses • Hypotheses need to be tested to see if they are supported or disproved. • Disproved hypotheses are rejected. • Hypotheses can be supported but not proven. • There are several ways to test a hypothesis: • Gathering relevant historical information. • Make additional observations from the natural world. • Experimentation

20. Experimentation • An experiment is a re-creation of an occurrence. • It tests whether or not the hypothesis can be supported or rejected. • Experiments must be controlled. • This means that all aspects except for one variable must be kept constant. • They usually include any two groups. • Experimental group: variable is altered • Control group: variable is not altered

21. Experimental design • The variable that is altered is called the independent variable. • Experiments should have only one independent variable. • The variables that change in response to the independent variable are called dependent variables. • Changes in the dependent variables are documented as data. • Data from the experiment is analyzed and hypotheses are rejected and revised or supported.

22. A sample experiment • Hypothesis: Male sex hormones produced by the testes stimulate male birds to sing. • Experimental group: Male birds with testes removed at birth. • Control group: Male birds subjected to a similar surgery that were allowed to develop normally with testes. • Independent variable: presence or absence of testes. • Dependent variable: presence of singing behavior • Data: Male songbirds without testes do not exhibit singing behavior. • Conclusion: Hypothesis is supported.

23. Figure 1_05

24. Experimental data • Experiments must: • Use large numbers of subjects or must be repeated several times (replication) • Be independently reproducible. • The validity of experimental results must: • Be tested statistically. • Be scrutinized by other scientists. • If the hypothesis is supported by large experimental data, it leads to a theory.

25. 1953年Waston & Crick解讀 DNA double helix的結構; 並於1962年獲得諾貝爾獎

27. Theory • A theory may be defined as a widely accepted, plausible general statement about a fundamental concept in science. • The germ theory states that infectious diseases are caused by microorganisms. • Many diseases are not caused by microorganisms, so we must be careful not to generalize theories too broadly. • Theories continue to be tested. • Exceptions identified • Modifications made

28. A scientific law • A scientific law is a uniform and constant fact of nature that describes what happens in nature. • An example: All living things come from pre-existing living things. • Scientific laws promote the process of generalization. • Inductive reasoning • Since every bird that has been studied lays eggs, we can generalize that all birds lay eggs. • Once a theory becomes established, it can be used to predict specific facts. • Deductive reasoning • We can predict that a newly discovered bird species will lay eggs.

29. Scientific communication • Data is shared with the scientific community through research articles published in scientific journals. • These articles are usually scrutinized by other scientists before they are published. • Scientists present preliminary data at conferences. • Scientists collaborate directly by phone, e-mail, and skype.

30. 1.3 Fundamental attitudes in science • Scientists must distinguish between opinions and scientific facts. • Scientists’ opinions may become facts if supported by data. • A good scientist must • be skeptical. • not be biased. • be honest in analyzing and reporting data. • The critical difference between science and non-science is that in science, one can test the principle. In non-science, one may not be able to.

31. Theoretical vs. Applied Science • Initially, some scientific data seems to be purely informational and not very practical. • Practical applications usually follow the discoveries of basic science. • The discovery of the structure of DNA has led to new drug treatments for many diseases. (antibiotics, hormones, enzymes) • The discovery of microorganisms has led to a dramatic decrease in infectious disease and food preservation. (vaccination against rabies, pasteurization for the preservation of food)

32. Science vs. Nonscience • Scientists continually challenge and test principles to determine cause-and-effect relationships. • Biology, Physics, Chemistry, Astronomy • Nonscientists cannot test their hypotheses directly and often cannot establish cause-and-effect relationships. • History, Literature, Philosophy, Art, Sociology, etc.

33. Pseudoscience • A deceptive practice that uses the language of science to convince people into thinking that a claim has scientific validity. • Marketing claims of nutritional supplements. • Marketing claims of organic foods. Fig. 1.11 Pseudoscience- “Nine out of 10 Doctors Surveyed Recommend Brand X”

34. Limitations of science • The scientific method can only be applied to questions that have a factual base. • Questions of morality, values, social issues and attitudes cannot be tested scientifically. • Science is limited by scientists. • People are fallible. • The sun orbits the earth. • But, science is self-correcting. • New data shapes new hypotheses. • The earth rotates on its axis, so maybe the earth orbits the sun.

35. 1.4 The science of biology • The study of living things. • Theoretical biology • Evolutionary biology, animal behavior, biochemistry • Applied biology • Medicine, crop science, plant breeding, wildlife management

36. What makes something alive? • Living things can manipulate energy and matter.

37. Characteristics of living things (I) • Metabolic processes • Organisms gain and store energy in the chemical bonds in the nutrients they take in. • Generative processes • Organisms grow by increasing the number of cells. • Organisms reproduce either sexually or asexually.

38. Characteristics of living things (II) • Responsive processes • Organisms respond to changes in their environment. • Irritability: the ability to recognize a stimulus and respond to it quickly. • Individual adaptation: a longer term response to an environmental change. • Evolution: changes in a population over time.

39. Characteristics of living things (III) • Control processes • Enable organisms to carry out metabolic processes in the right order. • Coordination: Enzymes coordinate metabolic reactions. (e.g., handling nutrients) • Regulation: Enzymes are regulated in order to maintain homeostasis. (e.g., exercise) • Unique structural organization • Organisms are made of cells. • Each kind of organism has specific structural characteristics

40. Levels of biological organization (I) • Biosphere—the worldwide ecosystem. • Ecosystem—communities that interact with one another in a particular place. • Communities—populations of different organisms interacting with each other in a particular place. • Population—a group of individual organisms in a particular place. • Organism—an independent living unit.

41. Levels of biological organization (II) • Organ system—many organs that perform a particular function. • Organ—many tissues that perform a particular function. • Tissue—many cells that perform a particular function. • Cell—simplest unit that shows characteristics of life. • Molecules—specific arrangements of atoms. • Atoms—the fundamental units of matter.

42. Significance of biology • Biology has significantly contributed to our high standard of living. • For example: • Advanced food production • Significant progress in health • Advances in disease control • Advances in plant and animal breeding • Advances in biotechnology • Progress in genome studies

43. Biological research improves food production

44. Edward Jenner and the Control of Smallpox

45. The Consequences of Not Understanding Biological Principles • Lack of Understanding … Ecological Systems • The damage Caused by Exotic Species • Ethical Concerns • Major advances in health care • Many people lack even the most basic health care, while the rich nations of the world spend millions of dollars to have cosmetic surgery …

46. Figure 1_20a

47. Figure 1_20b

48. Future Directions in Biology • Control of the human population • Curing hereditary disease • Between genetic info. and such diseases • Alzheimer’s disease • Stroke • Arthritis • Cancer • AIDS Ecology: Climate change, pollution, human population