The Science of Biology

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Adela Hopkins
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1 The Science of Biology

2 Warm Up: Vocabulary l Work in groups at your table to come up with basic scientific method vocabulary. Discuss and define these words in your groups.

3 Defining Key Terms l Science- an organized way of using evidence to learn about the natural world. l Biology- the study of life. l Observation- the process of gathering information

4 Defining Key Terms l Data- the information gathered from observation. l Quantitative- expressed as numbers l Qualitative- descriptive, involves characteristics or qualities (no numbers)

5 Defining Key Terms (continued) l Inference- a logical interpretation based on prior knowledge or experiences. l Hypothesis- a proposed scientific explanation for a set of observations. l Hypotheses must be testable!! l Must be falsifiable! l Typically written in an If.then format. (If independent variable, then dependent variable)

6 Think About It l You see a plant that is starting to wilt. It does not appear dead, but clearly needs some love. Is this an observation or an inference? l In your table groups, come up with as many inferences as you can.

7 Scientific Process l Asking a Question l Forming a Hypothesis l Setting Up a Controlled Experiment l Collecting Data l Analyzing Results l Drawing Conclusions

8 Science As A Way Of Understanding l Truths About Science l It is an ongoing process l Scientific understanding is always changing. l Science explores the universe and way many systems and processes interact. l Qualities of a Good Scientist l Skeptical l Open-Minded l Come up with one on your own!

9 Exit Slip l In KY, all individuals are required to wear seatbelts in moving vehicles. How could scientific research have had an impact on this decision?

10 Warm-Up Exercise l Is a scientific hypothesis acceptable if there is no way to demonstrate that the hypothesis is wrong? Explain.

11 Experimental Design l Controlled Experiment- an experiment that is designed to compare and experimental group to a control group. l Independent Variable- what is changed. l Dependent Variable- what is measured. l Controlled Variables- factors that remain the same between experimental groups. *Observations and experimental results must be repeatable in order for an experiment to be considered valid.

12 Theories l Theory- a well tested explanation that unifies a broad range of observations. l To be valid a theory must pass several tests: l It must explain observa2ons clearly and consistently. l Experiments that illustrate the theory must be repeatable. l You must be able to predict results from the theory.

13 Modeling l Models- a representa2on of an object or event that can be studied to understand the real object or event. l Types of Models l Drawings on paper l Real objects used to help us picture things we cannot see l A mental picture l A set of rules or mathema2cal rela2onships that describe how something works

14 Warm Up Calvin is conducting a study on the effects of exercise on personal happiness. He plans on having one group run/walk 6 miles per week and lift weights 3 times a week. He plans to have the other group maintain their normal daily routines, which does not include any exercise whatsoever. l Come up with a hypothesis, independent and dependent variables, identify the experimental group and the control group. l Evaluate this study. What are some of the problems, and how could it be better?

15 Where Do Living Things Come From? l Spontaneous Generation- living things can arise spontaneously from non-living things. l While this was the common belief for many years, we now know that it is not true and scientists all over the world prescribe to the idea of biogenesis. l Biogenesis- all living things come from other living things.

16 Redi s Experiment on Spontaneous Generation

17 Repeating Investigations l John Needham l Claimed that spontaneous generation could occur under the right conditions. l Heated sealed flask of gravy and found microorganisms (thought heat would kill any living things in gravy) l Found gravy swarming with activity.

18 Repeating Investigations l Lazzaro Spallanzani l Boiled 2 flasks of gravy, sealed 1 immediately and left the other open (thought boiling would definitely kill microorganisms). l Open jar was full of life. Sealed jar was uncontaminated.

19 Spallanzani s Test of Redi s Findings

20 Pasteur s Test of Spontaneous Generation Pasteur showed that all living things come from other living things. (biogenesis)

21 Exit Slip l What does the term spontaneous generation mean? l How does a scientific theory compare with a scientific hypothesis?

22 Warm-Up l There are several things that are similar between my fish and the second hand of a clock. Name some of the similarities as well as some of the differences and think about what makes the fish living but the clock not.

23 Characteristics of Living Things l Living things are made up of units called cells. l A cell is the smallest unit of an organism that can be considered alive. l Eukaryotes- contains nucleus (that houses DNA) and membrane-bound organelles; includes many forms of life (plants, animals, fungi). l Prokaryotes- does not have a nucleus (still has DNAfree floating in the cytoplasm); does not have organelles; smaller and less complex; includes bacteria l Living things reproduce. l Sexual Reproduction- 2 parents are united to form a genetically unique offspring. l Asexual Reproduction- a single parent produces offspring that are identical to itself.

24 Characteristics of Living Things l Living things are based on a universal genetic code. l This information is needed to live, grow, and reproduce. l Chromosomes contain genes (which are passed from parent to offspring) that are made up of DNA. l Living things grow and develop. l Cells undergo differentiation to perform different functions.

25 Characteristics of Living Things l Living things obtain and use materials and energy. l All organisms must take in materials and energy to grow, develop, and reproduce. l Metabolism- the sum of all chemical reactions in the body. l Anabolism- reactions that require energy. l Catabolism- reactions that release energy. l Producers (autotrophs)- make their own energy. l Consumers (heterotrophs)- feed on producers (and other consumers) for their energy. l Living things respond to their environment. l Organisms detect and respond to stimuli from their environment.

26 Characteristics of Living Things l Living things maintain a stable environment. l Although conditions outside an organism may change dramatically, most organisms need to keep conditions inside their bodies constant. (Homeostasis) l Negative Feedback- reduces the stimulus. l Brings the body back to normal and restores homeostasis. l Positive Feedback- amplifies the stimulus. l Not typically involved in homeostasis. l Taken as a group, living things change over time. l Individuals do not change, but groups of organisms tend to evolve over time.

27 l FIGURE 1.14

28 Branches of Biology l l l l l l l l l Biosphere- all living things Biome- group of similar ecosystems Ecosystem- living things and their nonliving surroundings Community- populations that live together in a defined area Population- group of organisms of one type that live in the same area Organism- individual living thing Groups of cells- tissues, organs, and organ systems Cells- smallest functional unit of life Molecules- groups of atoms; smallest unit of most compounds

29 Microscopes l Microscopes- produce magnified images of structures that are too small to see with the unaided eye.

30 Light Microscopes l Produce magnified images by focusing visible light rays. l Uses 2 lenses to form an image. l The only microscope that can be used to study living things.

31 Electron Microscope l Use beams of electrons to produce images. l Can produce images up to 1,000x more detailed than light microscopes. l Cannot view living cells. l 2 Types: l Transmission Electron Microscopes (TEMs)- Has the most magnification. Used to view the fine structures inside a cell. (organelles) l Scanning Electron Microscopes (SEMs)- used to view the detailed surface of a specimen.

32 Early Microbiologists l Anton Van Leeuwenhoek l Viewed animalcules or microorganisms, in pond water, rain water, and dust. l Credited for advances in the microscope. l Robert Hooke l First to describe and coin the word cell.

33 Exit Slip l What is homeostasis? Give an example of how it is maintained. l What biological processes includes chemical reactions that break down materials? l List some observations that could be made to determine whether an object that is not moving is living or nonliving.

34 Warm Up l List at least two differences between sexual and asexual reproduction. l What does it mean/why is is necessary for cells to differentiate?

35 Making Measurements l Length- a measure of the straight- line distance between two points. l Mass- a measure of the amount of mafer in an object. l Weight- a measure of the gravita2onal force exerted on an object. (weight = mass x gravity) l Volume- a measure of the size of the body or region in three- dimensional space.

36 Units of Measurement l SI System- the standard units of measurements used by scientists. Quantity Unit Abbreviation Length Meter m Mass Gram g Time Second s Temperature Celsius C Volume Liter L

37 SI Prefixes l SI prefixes are used for very large and small measurements. l SI prefixes are all based in mul2ples of 10. l Ex: 5,000 kilometers = 500,000,000 cen2meters Kentucky Has Dark base unit Deep Coal Mines K kilo De deci H hecta C cen2 Da deca M milli

38 Class Practice l Convert 486 milliliters to cen2liters. l Convert 312 kilometers to meters. l Convert 0.32 hectagrams to decigrams.

39 You Try It! l Convert 1.85 meters to cen2meters. l Write 55 decimeters as meters. l Change 1.6 kilograms to grams.

40 Warm Up Exercise l How many milliliters are on 0.45 liters? l How many grams are in 500,000 kilograms?

41 Scientific Notation l Scien2fic Nota2on- a method of expressing a quan2ty as a number mul2plied by 10 to the appropriate power. (10 x ) l When you mul2ply in scien2fic nota2on, you ADD the exponents. l When you divide in scien2fic nota2on, you SUBTRACT the exponents.

42 Class Practice ü Write the following measurements in scien2fic nota2on. 800,000,000 meters kg 67,453 L

43 You Try It! ü Write the following measurements in scien2fic nota2on ml 42,000,000,000 km 89,265 g

44 Class Practice ü Write these measurements in long form. 4.5 x 10 3 g 1.99 x 10-8 cm x 10 4 m

45 You Try It! ü Write these measurements in long form x 10 5 dm x 10 3 cg 6.04 x 10-4 ml

46 Class Practice ü Perform the following calcula2ons (5.5 x 10 4 cm) x (1.4 x 10 4 cm) ü Perform the following calcula2ons 5.2 x 10 8 cm x 10 2 cm 3

47 You Try It! ü Perform the following calcula2ons (4.34 g/ml) x (8.22 x 10 6 g/ml) (3.8 x 10-2 cm) x (4.4 x 10-2 cm) x (7.5 x 10-2 cm) ü Perform the following calcula2ons 6.05 x 10 7 g 8.8 x 10 6 cm 3

48 Graphing Scientific Data l Line Graphs- show con2nuous changes l Bar Graphs- compare the values of items l Pie Graphs- show the parts of a whole

The Science of Biology

The Science of Biology Warm Up: Vocabulary Work in groups at your table to come up with basic scientific method vocabulary. Discuss and define these words in your groups. Defining Key Terms Science- an