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Welcome to BILD10: Fundamental Concepts of Modern Biology
Winter 2014
Dr. David Traver Professor of Cell and
Developmental Biology Natural Sciences Building 6107
All information is on website!! http://www.biology.ucsd.edu/classes/bild10.WI14
GOALS:
1. Learn that Biology is an Experimental Science
How do we know what we know?
What new questions raised are still to be tested?
2. Learn the structures and mechanisms of action for the smallest unit of life - the cell
Terminology (what is it?)
Functional Concepts (how does it work? themes?) Hierarchy, Connectivity (how do parts fit together?)
3. Learn how cells come together to form tissues and structures that are the
evolutionary building blocks of life on earth.
4. Inform you that Biology is pretty cool.
BILD10: Fundamental Concepts of Modern Biology
http://www.biology.ucsd.edu/classes/bild10.WI14
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Course Meetings
• Lectures Syllabus posted on website
Tuesday / Thursday, 2:00 - 3:20 pm, WLH 2001 NOTE! No Office Hours or Sections this week
• Midterm Exams Same time, Same place
#1 Tuesday, January 28th, 2:00 - 3:20 pm, WLH 2001 #2 Thursday, February 20nd, 2:00 - 3:20 pm, WLH 2001
• Final Exam New time, place to be determined
Thursday, March 20th, 3:00-6:00 pm
http://www.biology.ucsd.edu/classes/bild10.WI14
• Weekly Sections, starting Monday, January 13th 10 Section options (see website for final schedule) TA-led Discussions Review Problem Sets, Chapter reading, Q&A Not Required, but Highly Recommended! TA input on attendance/participation can affect grades
• Exam Review Sessions
TA-led Reviews and Q&A on the Weekends prior to all Exams.
Course Meetings http://www.biology.ucsd.edu/classes/bild10.WI14
Course TAs
Madie Chakoumakos Gitajali Das
Kishen Godhia Tiffany Guan Nidhi Khullar
Diana Kneiber Isabel Lin
Daniel McLaughlin Victor Shih Valerie Tran
Course Etiquette
• Arrive on Time • Turn off phones • Do not disturb others • Participate! Questions welcome
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• Reading of assigned text, as on syllabus
What is Life?, 2nd Edition, Jay Phelan
www.whfreeman.com/phelan2e
- Recommended to pre-read prior to lecture
NOTE! Students responsible for conversions if using old editions
• Problem Sets, to be posted on website - Not for credit, but Highly Recommended! - Announced in class when posted on the website - Reviewed in Sections the following week NOTE! Some questions will be re-used verbatim on exams
Course Work Exams
• NO MAKE UPS!
Please ensure that you can make all three exam times.
• Only pencil, scantron form and ID allowed, closed book and notes
• Zero tolerance for cheating of any kind
• Grading is not done on a typical curve
� Top 5% of students averaged and normalized to 100%. � Letter grades determined by 12.5% cutoffs, ex. A = 88.5-100%
• Final Grade:
• 10% Debate participation / reports • 20% Midterm Exam 1 • 20% Midterm Exam 2 • 50% Final Exam (Comprehensive)
Borderline grades will be influenced by participation in Sections
Course Grading
• Weekly Professor Office Hours
– Mondays 3:00-4:00 pm, Natural Science Building Room 6107
• Weekly TA Office Hours
- 10 options each week, as posted on website
Resources
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• From Instructor to Student
Students must have functional email account - working account as listed on TritonLink - make sure instructor’s email not seen as spam - make sure inbox is not full
• From Student to Instructor
- Include BILD10 in subject line - Use proper English - Include full name in note - Do not expect instant replies
Email Contact
Biology Student Affairs Undergraduate Office Pacific Hall 1129
Add / Drop Prereqs, Major etc.
Administrative ?
Chapter 1: Scientific Thinking
Your best pathway to understanding the world
Learning Goals
q Describe what science is. q Describe the scientific method. q Describe key aspects of well-designed
experiments. q Describe how the scientific method can be
used to help make wise decisions. q Describe the major themes in biology.
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1.1 What is science? What is biology?
Scientists q Are curious q Ask questions about how the world works q Seek answers
• Does the radiation released by cell phones cause brain tumors?
• Are anti-bacterial hand soaps better than regular soap?
• Do large doses of vitamin C reduce the likelihood of getting a cold?
“How do you know that is true?”
The single question that underlies scientific thinking
…the importance of questioning the truth of many “scientific” claims you see on merchandise packages or read in the newspaper or on the Internet.
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Can we trust the packaging claims that companies make?
clinical drug trials and evidence
CEO says: people “are really not scientifically minded enough to be able to understand a clinical study.”
You don’t have to be at the mercy of cranks, charlatans, advertising, or slick packaging.
q Learn exactly what it means to have scientific proof or evidence.
q Learn what it means to think scientifically.
The most important questions in biology:
q What is the chemical and physical basis for life and its maintenance?
q How do organisms use genetic information to build themselves and to reproduce?
The most important questions in biology:
q What are the diverse forms that life on earth takes and how has that diversity arisen?
q How do organisms interact with each other and with their environment?
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Take-home message 1.1
q Through its emphasis on objective observation, description, and experimentation, science is a pathway by which we can come to discover and better understand the world around us.
A brief glance at any newspaper will reveal…
1.2 Biological literacy is essential in the modern world.
q Why are unsaturated fats healthier for you than saturated fats?
q What are allergies? Why do they strike children from clean homes more than children from dirty homes?
q Why do new agricultural pests appear faster than new pesticides?
Take-home message 1.2
q Biological issues permeate all aspects of our lives.
q To make wise decisions, it is essential for individuals and societies to attain biological literacy.
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1.3 The scientific method is a powerful approach to understanding the world.
If science proves some belief of Buddhism wrong, then Buddhism
will have to change —Dalai Lama, 2005
Why and when do people develop superstitions?
Can animals be superstitious?
Understanding How the World Works
q Someone wonders about why something is the way it is and then decides to try to find out the answer.
q This process of examination and discovery is called the scientific method.
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FIGURE 1-5 The scientific method: five basic steps and one flexible process FIGURE 1-5 The scientific method: five basic steps and one flexible process
FIGURE 1-5 The scientific method: five basic steps and one flexible process FIGURE 1-5 The scientific method: five basic steps and one flexible process
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FIGURE 1-5 The scientific method: five basic steps and one flexible process FIGURE 1-5 The scientific method: five basic steps and one flexible process
FIGURE 1-5 The scientific method: five basic steps and one flexible process
What should you do when something you believe in turns out to be wrong?
This may be the most important feature of the scientific method:
it tells us when we should change our minds.
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The scientific method can be used to examine a wide variety of issues.
q Does echinacea reduce the intensity or duration of the common cold?
q Does chemical runoff give rise to hermaphrodite fish?
q Does shaving hair from your face, legs, or anywhere else cause it to grow back coarser or darker?
Does taking echinacea reduce the intensity or duration of the common cold?
To be most useful, a hypothesis must accomplish two things:
1. It must clearly establish mutually exclusive alternative explanations for a phenomenon.
2. It must generate testable predictions.
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Devising Testable Predictions
q We can only evaluate the validity of a hypothesis by putting it to the test.
q Researchers often pose a hypothesis as a negative statement, proposing that there is no relationship between two factors.
The Null Hypothesis q A negative statement that proposes that
there is no relationship between two factors
q These hypotheses are equally valid but are easier to disprove.
q An alternative hypothesis
q It is impossible to prove a hypothesis is absolutely and permanently true.
Null and Alternative Hypotheses
q Echinacea reduces the duration and severity of the symptoms of the common cold. Or, as a null hypothesis:
• Echinacea has no effect on the duration or severity of the symptoms of the common cold.
Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold.
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1.8 Step 4: Conduct a critical experiment.
an experiment that makes it possible to decisively determine whether a particular
hypothesis is correct
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1.9 Step 5: Draw conclusions, make revisions.
Trial and error
The Role of Experiments
q What is important is that we attempt to demonstrate that our initial hypothesis is not supported by the data.
q If it is not, we might then adjust our hypothesis.
Making Revisions q Try to further refine a hypothesis.
q Make new and more specific testable predictions.
Does echinacea help prevent the common cold?
Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold.
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1.10 When do hypotheses become theories?
Two distinct levels of understanding that scientists use in describing our
knowledge about natural phenomena
Take-home message 1.10
q Theories are hypotheses that have been so strongly supported by empirical observation that the scientific community views them as very unlikely to be altered by new evidence.
1.11 Controlling variables makes experiments more powerful.
Elements Common to Most Experiments
1. Treatment • any experimental condition applied to individuals
2. Experimental group • a group of individuals who are exposed to a particular
treatment 3. Control group
• a group of individuals who are treated identically to the experimental group with the one exception: they are not exposed to the treatment
4. Variables • characteristics of your experimental system that are
subject to change
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Controlling Variables
q the most important feature of a good experiment
q the attempt to minimize any differences between a control group and an experimental group other than the treatment itself
FIGURE 1-14 No controls
FIGURE 1-14 No controls FIGURE 1-14 No controls
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FIGURE 1-14 No controls FIGURE 1-14 No controls
FIGURE 1-14 No controls FIGURE 1-14 No controls
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FIGURE 1-14 No controls FIGURE 1-14 No controls
FIGURE 1-14 No controls
The Placebo Effect
q The phenomenon in which people respond favorably to any treatment
q The placebo effect highlights the need for comparison of treatment effects with an appropriate control group.
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Clever Hans Experimental Designs
q Blind experimental design • The experimental subjects do not know
which treatment (if any) they are receiving.
q Double-blind experimental design • Neither the experimental subjects nor the
experimenter know which treatment the subject is receiving.
Hallmarks of an Extremely Well-designed Experiment
q Blind/double-blind strategies
q Randomized • The subjects are randomly assigned into
experimental and control groups.
1.12 Repeatable experiments increase our confidence.
Can science be misleading? How can we know?
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1.15 Statistics can help us in making decisions.
Statistics
A set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather.
q Drawing conclusions based on limited observations is risky.
q Measuring a greater number of people will generally help us draw more accurate conclusions about human height.
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Take-home message 1.15
q Because much variation exists in the world, statistics can help us evaluate whether differences between a treatment and control group can be attributed to the treatment rather than random chance.
1.16 Pseudoscience and misleading anecdotal evidence can obscure the truth.
1. Pseudoscience: individuals make scientific-sounding claims that are not supported by trustworthy, methodical scientific studies.
2. Anecdotal observations: based on only one or a few observations, people conclude that there is or is not a link between two things.
Science is a way to call the bluff of those who only pretend to knowledge. It is a bulwark against mysticism, against superstition, against religion misapplied to where it has no business being. If we’re true to its values, it can tell us when we’re being lied to.
—Carl Sagan
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1.18 A few important themes tie together the diverse topics in biology.
Four Chief Areas of Focus 1. The chemical, cellular, and energetic
foundations of life 2. The genetics, evolution, and behavior of
individuals 3. The staggering diversity of life and the unity
underlying it 4. Ecology, the environment, and the subtle
and important links between organisms and the world they inhabit
Take-home message 1.18
q Although the diversity of life on earth is tremendous, the study of life is unified by the themes of hierarchical organization and the power of evolution.
Today’s Lecture:
• Please check / fix email.
• Read Chapter 1.
• Read Chapter 2.
Thursday’s Lecture:
Reminders:
• No TA Sections or office hours this week.
