Ch 1: The Science of Biology

1. What is Science? Science in Context Ch 1: The Science of Biology Studying Life

2. A. What Science Is and Is Not • The goal of science is toinvestigateand understandthe natural world through explanations. 2. Science– an organizedway of gathering and analyzing evidenceto learn about the naturalworld. a. Science refers to the body of knowledgebuilt up over time. 3. Why is there uncertainty in science?

3. Thinking like a Scientist:Scientific Methodology 1. Observation– the act of noticing and describing events or processes in a careful, orderly way using the five senses 2. Inference– interpretation based on prior knowledge (what scientists already know) or experience “ a logical conclusion”. Statement Observation Inference X Object A is round and orange. • What is object C? X Object A is a basketball. X Object C is round and black and white. • Object C is a soccer ball. X Object C is larger than Object B. X Object B is smooth. X Object B is a table-tennis ball. X X Each object is used in a different sport.

4. Explaining and Interpreting Evidence 1. Hypothesis – proposed scientific explanation for a set of observations to make inferences. 2. A hypothesis can result from prior knowledge, inference, or creative imagination 3. A hypothesis should be testable Science as a Way of Knowing 1. Science is an ongoing process – it is always changing 2. Good scientists are constantly questioning 3. Having an open-mind is critical to discovery

5. How Scientists Work Designing Controlled Experiment 1. Ask a Question • Form a hypothesis– a statement that can be tested Always written has an “if” “then” “because” statement. 3. Setting up a controlledexperiment- investigation in which only a single factor is tested a. Experimental group – contains factor being tested b. Control group– does not contain the factor being tested c. Variables 1. independent variable – also known as the manipulatedvariable – the change 2. dependentvariable – also known as the respondingvariable – what you are measuring

6. 4. Recording and Analyzing data (experimental observations) a. Tables, Graphs, Charts, Etc. b. Qualitative – involves physicaldescription e.g. Blond hair, green eyes c. Quantitative – uses numbersor measurements e.g. 35 mm, 12 tables 5. Drawing a conclusion * Is hypothesis supported or refuted 6. Publishingand Repeating the work a. Experiment is only valid if it can be repeated b. Communication is essential

7. Mystery Worms A teacher collected some beetles from a rotting log and placed them in a container of dry oatmeal in her classroom. She kept the box covered with a light cloth so that the beetles could not escape. She also asked one of her students to add potato and apple pieces once a week to provide food and moisture for the beetles. After several weeks, the student reported that there were some strange-looking, wormlike organisms in the container.

8. Mystery WormsThink- pair-share • Formulate a hypothesis that might explain the presence of the “worms” in the container. • Explain in detail how you could test your hypothesis. • Identify the variables in your proposed experiment. • Identify the control group in your experiment. • What data would you collect during your experiment?

9. 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. Covered jars Uncovered jars PROCEDURE 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 No maggots appear Maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

10. Publishing and Repeating the work 1. Needham’s Test of Redi’s findings a. Possible due to Leeuwenhoek’s discovery of microscopic world. “animalcules” b. Sealed a bottle of gravy and heated it. Uses broth as the medium for life. c. Life was in it so life comes from the gravy. d. Believes he has proven spontaneous generation. 2. Spallanzani’s Test of Redi’s work a. Improves upon Needham’s design, thought he did not heat them enough. b. Concludes spontaneous generation is not possible

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

12. Publishing and Repeating the work 3. Pasteur’s test of Spontaneous generation a. Sets out to finally disprove the idea of spontaneous generation. b. Designs a special flask that allows air to reach the medium. c. Made significant contributions to the scientific community. d. Biogenesis – idea that living things come from other living things. Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

13. Designing an Experiment State the Problem Analyze Results Form a Hypothesis Draw a Conclusion Set Up a Controlled Experiment Publish Results Record Results Theory – a well tested explanation that unifiesa broad range of observations and hypotheses, and enables scientist to make accurate predications about new situations. Bias– a particular preference or point of view that is personal, rather than scientific. Want to avoid this!

14. 1–3 Studying Life BIO = lifelogy = the study of Biology= the science that seeks to understand the living world A. Characteristics of Living Things 1. Made Up of units called cells • cell –a collection of living material enclosed by a barrier that separates the cell from its surroundings. - Smallest unit of an organism. b. unicellular- one celled organism • multicellular – manycelled organism Introduction to cells video

15. 2.Reproduction - to produce new similar organisms a.Sexual-2 cells from different parents unite b. Asexual - new organism has 1 parent. One organism splits to form 2. Organism produces offspring identical to itself. 3. Based on a Universal Genetic Code a. The offspring will resemble the parents e.g. Dogs produce dogs b. DNA = deoxyribonucleic acid

16. 4. Growth and Development a. Growth – an increase in size b. Development – cells divide and change their shape and structure according to their intended function. * Give an example of a rapid and dramatic change in an animal*

17. 5. Need materialsand energy - to grow, develop, reproduce, and to just stay alive! a.anabolism: making complex substances from simple substances b.catabolism: breaking down complex substances into simpler ones. c.metabolism: The building up and breaking down of substances in an organism, as it carries out its life processes.

18. 6. Respond to the environment a. Stimulus: Anything in the environment that can cause an organism to react. 7. Maintaining Internal Balance (stable environment) a.Homeostasis– Steady state b. Organisms maintain constant internal conditions despite the external conditions 8. Evolution – change over time * important for a group’s survival in a changing world.

19. Characteristic Examples Living things are made up of units called cells. Many microorganisms consist of only a single cell. Animals and trees are multicellular. Living things reproduce. Maple trees reproduce sexually. A hydra can reproduce asexually by budding. Living things are based on a universal genetic code. Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees. Living things grow and develop. Flies begin life as eggs, then become maggots, and then become adult flies. Living things obtain and use materials and energy. Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat. Leaves and stems of plants grow toward light. Living things respond to their environment. Despite changes in the temperature of the environment, a robin maintains a constant body temperature. Living things maintain a stable internal environment. Taken as a group, living things change over time. Plants that live in the desert survive because they have become adapted to the conditions of the desert.

20. Branches of Biology 1.Biology is broken down into many fields such as botany, microbiology, ethology, and zoology. 2.Living things can be studied at various levels of organization as well.

21. Organism Individual living thing Biosphere The part of Earth that contains all ecosystems Biosphere Bison Ecosystem Community and its nonliving surroundings Tissues, organs, and organ systems Groups of Cells Hawk, snake, bison, prairie dog, grass, stream, rocks, air Nervous system Brain Nervous tissue Community Populations that live together in a defined area Smallest functional unit of life Cells Hawk, snake, bison, prairie dog, grass Nerve cell Population Group of organisms of one type that live in the same area Groups of atoms; smallest unit of most chemical compounds Molecules Bison herd DNA Water

22. Scientific Measurement 1. Decimal system- based on powers of 10 2. AKA International system of units or SI 3. Common system of measurement for scientists around the world

23. Conversions between large and small quantities K H Dk U d c m • This chart tells you two things: • How many places to move the decimal • In what direction to move the decimal

24. K H Dk U d c m • Examples: • 4.51 kg = ________g • 4587m = _________mm • 1.23 mL = ________L

25. Answers… 4 5 1 0 4.51 kg = 4510 g

26. 4587m = 4,587,000mm 4587 0 0 0

27. 1.23 mL = 0.00123 L