1. Chapter 1 Phylogenetic Diagram of Living Organisms Section 2 Themes in Biology

2. Chapter 1 Diversity and Unity of Life, continued Three Domains of Life –The three domains of life are Bacteria, Archaea, and Eukarya. –The six kingdoms include Archaea, Bacteria, Protista, Fungi, Plantae, and Animalia.

3. Section 3 The Study of Biology Chapter 1 Objectives Outline the main steps in the scientific method. Summarize how observations are used to form hypotheses. List the elements of a controlled experiment. Describe how scientists use data to draw conclusions. Compare a scientific hypothesis and a scientific theory. State how communication in science helps prevent dishonesty and bias.

4. Section 3 The Study of Biology Chapter 1 Scientific Processes

5. Section 3 The Study of Biology Chapter 1 Observing and Asking Questions The process of science begins with an observation. An observation is the act of perceiving a natural occurrence that causes someone to pose a question. Observation: Flies were observed around the carcasses at the butcher shops. Question: Where do the flies at the butcher shop really come from? Does rotting meat turn into or produce the flies?

6. Section 3 The Study of Biology Chapter 1 Forming a Hypothesis A hypothesis is a proposed explanation for the way a particular aspect of the natural world functions. Hypothesis: Rotten meat does not turn into flies. Only flies can make more flies.

7. Section 3 The Study of Biology Chapter 1 Forming a Hypothesis, continued Predicting –To test a hypothesis, scientists make a prediction that logically follows from the hypothesis. Prediction: If meat cannot turn into flies, rotting meat in a sealed (fly-proof) container should not produce flies or maggots.

8. Section 3 The Study of Biology Chapter 1 Designing an Experiment Performing the Experiment –A controlled experiment compares an experimental group and a control group and only has one variable.

9. Section 3 The Study of Biology Chapter 1 Designing an Experiment, continued Performing the Experiment –The control group provides a normal standard against which the biologist can compare results of the experimental group. –The experimental group is identical to the control group except for one factor.

10. Section 3 The Study of Biology Chapter 1 Designing an Experiment, continued Performing the Experiment –The experimenter manipulates the independent variable. –The experimenter measures the dependent variable because it is is affected by the independent variable.

11. Section 3 The Study of Biology Chapter 1 Designing an Experiment, continued Testing the Experiment –Experiments should be conducted without bias and they should be repeated.

12. Testing: Wide-mouth jars each containing a piece of meat were subjected to several variations of “openness” while all other variables were kept the same. control group — These jars of meat were set out without lids so the meat would be exposed to whatever it might be in the butcher shop. experimental group(s) — One group of jars were sealed with lids, and another group of jars had gauze placed over them. replication — Several jars were included in each group.

13. Section 3 The Study of Biology Chapter 1 Collecting and Analyzing Data Analyzing and Comparing Data –Scientists analyze data to draw conclusions about the experiment performed. Data: Presence or absence of flies and maggots seen in each jar was recorded. In the control group of jars, flies were seen entering the jars. Later, maggots, then more flies were seen on the meat. In the gauze- covered jars, no flies were seen in the jars, but were observed around and on the gauze, and later a few maggots were seen on the meat. In the sealed jars, no maggots or flies were ever seen on the meat.

14. Section 3 The Study of Biology Chapter 1 Drawing Conclusions Making Inferences –An inference is a conclusion made on the basis of facts and previous knowledge rather than on direct observations.

16. Conclusion(s): Only flies can make more flies. In the uncovered jars, flies entered and laid eggs on the meat. Maggots hatched from these eggs and grew into more adult flies. Adult flies laid eggs on the gauze on the gauze- covered jars. These eggs or the maggots from them dropped through the gauze onto the meat. In the sealed jars, no flies, maggots, nor eggs could enter, thus none were seen in those jars. Maggots arose only where flies were able to lay eggs. This experiment disproved the idea of spontaneous generation for larger organisms.

17. Section 3 The Study of Biology Chapter 1 Drawing Conclusions, continued Applying Results and Building Models –Scientists often apply their findings about the natural world to solve practical problems.

18. Section 3 The Study of Biology Chapter 1 Constructing a Theory A theory is a set of related hypotheses confirmed to be true many times, and it can explain a great amount of data.

19. Section 3 The Study of Biology Chapter 1 Communicating Ideas Publishing a Paper –Scientists submit research papers to scientific journals for publication. –In peer review, the editors of a journal will send submitted papers out to experts in the field who anonymously read and critique the paper.

20. Section 3 The Study of Biology Chapter 1 Honesty and Bias Communication between scientists about their methods and results helps prevent dishonesty and bias in science.

21. Section 3 The Study of Biology Chapter 1 Honesty and Bias Conflict of Interest –The threat of a potential scandal based on misleading data or conclusions is a powerful force in science that helps keep scientists honest and fair.