Chapter 1 The science of biology

1-1 What is Science? an organized way of using evidence to learn about the natural world. also used to describe the body of knowledge built up over the years Always changing (Pluto, 2006) http://news.nationalgeographic.com/news/2006/08/060824-pluto-planet.html

What are the goals of science? investigate and understand the natural world. Collect data/ observations To explain events in the natural world use those explanations to make useful predictions.

Thinking like a scientist… Observation: the process of gathering information about events or processes in a careful, orderly way.

Thinking like a scientist… Data: the information gathered from observations Quantitative: involve numbers/measurements Qualitative: descriptive/ not easily measured Find patterns/trends

Thinking like a scientist… Inference: a logical interpretation based on prior knowledge or experience (data) Footprints/fossils Scientists may use inferences at first but MUST backup with facts

Explaining and Interpreting Evidence Hypothesis: proposed scientific explanation for a set of observations May be accepted or rejected Must be able to be tested… Using controlled experiments and collecting new data …and re-tested Validity Reliability

Collaboration Scientists and researchers often work in teams Critical analysis/sharing of ideas Review process helps to ensure valid results

Science is always changing A continuous process involving: Asking questions Observing Making inferences Testing hypotheses A good scientist is a skeptic of both new and old ideas Men vs. women

Scientific Thinking Scientists are trained to use a scientific methods as a guide to make intelligent decisions However…

Other factors involved in decision making Society/community Economic considerations Laws Morals/ethics Stem cell research? Abortion?

5 questions a biologist might ask about:

1-2 How Scientists Work Ask questions and test them! Scientific Method State the problem Collect information Form a hypothesis Design and conduct an experiment Record observations and data Check results/retest Draw your conclusions Communicate your results

Designing a Controlled Experiment Variables must be controlled Dependent/responding variable Independent/ manipulated variable Controlled variables Record results/analyze findings Draw a conclusion

Spontaneous Generation as an Example What if we wanted to test it? Francesco Redi’s hypothesis (p.9)

Repeating Investigations Anton van Leeuwenhoek- “animalcules” John Needham challenges Redi “SG just needs the right conditions” Lazzaro Spallanzani adds his two cents Boils gravy longer- seals flask Some argued SG needed air (a “life force”) Pasteur settles it with his curved flask

The Scientific Method: State the problem Collect information Form a hypothesis Design and conduct an experiment Record observations and data Check results/retest Draw your conclusions Communicate your results

When Experiments Are Not Possible… Oscar Pistorius Olympic Debate Field studies Ethical concerns If they are careful, scientists are still able to discover reliable patterns to make inferences about

So what if your hypothesis is accepted? Scientific Theory: a well tested explanation that unifies a broad range of observations a currently acceptable idea- universally accepted to be true NOT a fact Scientific Law = fact (ex: gravity)

1-3 Studying Life bio = “life” logy = “the study of” How do we know what is “living” and what is “nonliving”?

8 Characteristics of Living Things 1. All living things are made up of cells Unicellular Multicellular

2. All living things reproduce Sexual Asexual

3. All living things are based on a universal genetic code DNA determined the traits you receive from your parents

4. All living things grow and develop Increase in size Cell division for specific “parts”

5. All living things obtain and use materials and energy To grow and develop To simply stay alive Metabolism: the breakdown of materials an organism uses to carry out its life processes

6. All living things respond to their environment Stimulus External Internal

7. All living things maintain a stable environment Homeostasis- internal feedback mechanism Shivering and sweating

8. All living things, viewed as a group, change over time. evolution

Studying Biology Different branches: anatomy, botany, microbiology, taxonomy, cytology, etc. Levels of Organization Molecular Cellular Groups of cells Organisms Populations Communities Ecosystems Biosphere

1-4 Tools and Procedures The Metric System- a common decimal system of units based on multiples of 10 KHDUDCM: “King Henry Doesn’t Usually Drink Chocolate Milk” Common Metric Units Length: meter Mass: gram Volume: liter Temperature: Celcius

Analyzing Data Today, computers do the bulk of biological data analysis Tables and Graphs

Microscopes Light microscope Electron microscope Up to 1000x magnification Compound light microscopes Two lenses- light passes through an organism Dyes and stains Electron microscope Can view very small organisms Must be used in a vacuum TEM (thru) and SEM (over surface)

Laboratory Techniques Cell cultures Single cell placed in a nutrient dish- grows into a “culture” of cells Cell fractionation Separates the different cell parts for individual study Uses a blender and centrifuge

Vocabulary Review 1. This is the study of the natural world. It can also mean the body of knowledge we’ve built up based on these studies. A. biology B. anatomy C. science D. observation

2. This occurs when living things come from nonliving things. A. metabolism B. homeostasis C. hypothesis D. spontaneous generation

3. This is the process of gathering information about events/processes in a careful, orderly way. A. data B. inference C. hypothesis D. observation

4. This is a logical interpretation based on prior knowledge and experiences. A. inference B. hypothesis C. theory D. qualitative data

5. This is a well-tested explanation that unifies a broad range of observations. A. theory B. hypothesis C. stimulus D. inference

6. This is a proposed scientific explanation for a set of observations. A. inference B. theory C. hypothesis D. a guess

7. This type of reproduction requires only one parent. A. asexual B. sexual C. unisexual D. mating

8. A collection of living matter enclosed by a barrier that separates it from it’s environment. It is the smallest unit of life. A. atom B. cell C. molecule D. organism

9. A controlled experiment occurs when you change only this in your set-up. A. responding variable B. manipulated variable C. dependent variable D. control variable

10. A signal to which an organism responds A. homeostasis B. stimulus C. metabolism D. trigger

11. This is the branch of science that studies the living world. A. science B. anatomy C. botany D. biology

12.This process requires an internal feedback mechanism in order to maintain internal balance in an organism. A. metabolism B. stimulus C. homeostasis D. thermostat

13.This is a lab technique where cells are broken down into their individual parts. A. cell fractionation B. cell colonies C. cell cultures D. electron microscopy

14. The two types of microscopes are: A. compound and light B. light and proton C. compound and electron D. light and electron

15. The combination of chemical reactions through which an organism builds up and breaks down material as it carries out it’s life processes. A. homeostasis B. stimulus C. metabolism D. evolution

ANSWERS: 1. C 9. B 2. D 10. B 3. D 11. D 4. A 12. C 5. A 13. A 6. C 14. D 7. A 15. C 8. B