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Ø Objectives of the course Ø Grading Ø Exam policies (ParScores)
Replacing lowest exam grade Ø Attendance: Mandatory Ø Classroom policies
Succeeding In This Class
Ø Take your school work seriously
Ø Come to class prepared
Ø Attend all lectures
Ø Be an active participant
Succeeding In This Class
Ø Allow some “biology” time every day
Ø Read your notes and rewrite them (within 24 hours is best)
Ø Please read the textbook
Ø Prepare a list with the new terms and define them
Ø Prepare flash cards
Ø Form study groups
Ø Discuss any questions with me
Ø Come to office hours
Ø Tutorial Services: you will need to create a To schedule a tutoring appointment, you need to create a “MyWcOnline” account if you don't already have one Phone number: (951) 222-8170 MLK Bldg., Room 232
Succeeding In This Class
Biology
Ø Bios = life (from Greek)
Ø -logy/-ology = scientific study of a subject
Ø Biology = scientific study of life
The word science is derived from a Latin word “scire” meaning to know, to understand
Science: The systematic study of the observable world and how it works
Critical thinking is a big part of science judging information before accepting it
Science is both a body of knowledge and the process to acquire this knowledge
Scientific Method
Ø Is not a rigid procedure
Ø Based on evidence
Process consisting of a series of steps used to make, test and evaluate hypotheses
Hypothesis: testable explanation of a natural phenomenon/educated guess
Prediction: statement about a condition that should occur if the hypothesis is correct
Independent variable: condition or treatment controlled by the experimenter/ treatment
Variable: a characteristic or event that differs among individuals or over time
Experiment: test designed to support or falsify a prediction
Dependent variable: observed result that is influenced by the independent variable
Control group: identical to an experimental group, but without exposure to the independent variable
Experimental group: receive a certain treatment or have certain characteristics
Sample size and replications
Butterflies and Birds
Researchers investigated whether certain peacock butterfly behaviors defend them against predatory birds
Initial observations: When a peacock butterfly rests, it folds its wings, so only the dark underside shows When a butterfly sees a predator approaching, it flicks its wings open, producing a hissing sound and a series of clicks
Ø First hypothesis: wing-flicking exposes brilliant spots that resemble owl eyes
Ø Second hypothesis: hissing and clicking sounds may be an additional defense that deters predatory birds
Experimental design:
u Paint the wing spots of some butterflies black
u Remove sound-making wing part of others
u Apply both treatments Ø Place butterfly into cage
with a hungry blue tit Ø Observe for 30 minutes
Conclusions:
Ø The test results supported the hypotheses Ø Predatory birds are indeed deterred by
peacock butterfly sounds, and even more so by wing spots
Inductive reasoning: drawing a conclusion based on many specific observations
Deductive reasoning: using a general idea to make a conclusion about a specific case
Sampling error
More Terms relating to scientific inquiries
Probability Statistically significant Scientific Theory Law of nature
Science addresses only testable ideas about observable events and processes It does not address anything that is not testable, such as beliefs and opinions
Limitations of Science
Forms of Life Share Common Properties
Ø Order Ø Energy and nutrients Ø Response to stimuli Ø Homeostasis Ø Use of DNA as hereditary material during
reproduction Ø Growth and development Ø Evolutionary adaptation
Order Life has nested levels of organization
Specific organization of components in a biological system and their interaction give rise to emergent properties
New properties that arise in each step upward in the hierarchy of life as a result of interactions between components and proper arrangement of components
Emergent Properties
“An organism is a living whole greater than the sum of its parts”
A Closer Look at Biological Organization
Life organization extends from the microscopic scale of atoms and molecules to the global scale of the biosphere
Ø Atom Ø Molecule/ Biological
Molecules Ø Organelle/Cell*
§ Cells are the fundamental units of life
Ø Tissue Ø Organ
A Hierarchy of Biological Organization
Ø Organ system Ø Organism (Beyond the level of
organisms) Ø Population Ø Community Ø Ecosystem*
§ Producers § Consumers § Decomposers § Physical environment
Ø Biosphere
Nutrients and Energy Processing
How do organisms obtain energy? Ø Producers Ø Consumers
Why do organisms need energy?
Ø Power activities and chemical reactions
Nutrient: substance acquired from the environment and required for growth and survival
producer acquiring energy and nutrients from the environment
consumer acquiring energy and nutrients by eating a producer
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ENERGY IN SUNLIGHT
Producers harvest energy from the environment. Some of that energy flows from producers to consumers.
Nutrients that get incorporated into the cells
of producers and consumers are eventually released back into
the environment (by decomposition, for example). Producers then take up some of the
released nutrients.
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plants and other self-feeding organisms PRODUCERS
animals, most fungi, many protists, bacteria CONSUMERS
5 All of the energy that enters the world of life eventually flows out of it, mainly as heat released back to the environment.
Homeostasis
Living organisms have the ability to maintain a stable internal body environment even in the face of a fluctuating external environment
Living Organisms Use DNA Ø DNA (deoxyribonucleic acid) carries hereditary
information that guides: Ø Development: multistep process by which the
first cell of a new multicelled organism gives rise to an adult
Ø Growth: increase in the number, size, and volume of cells
Ø Reproduction: processes by which individuals produce offspring
Ø Inheritance: transmission of DNA to offspring Ø All organisms inherit their DNA from one or
two parents Ø DNA is the basis of similarities in form and
function among organisms: All forms of life use the same genetic code to translate the information stored in DNA into proteins
Ø Small variations in DNA give rise to differences among individuals and among types of organisms
The Diversity of Life
Taxonomy (Carolus Linnaeus) Science that deals with the identification and the classification of living organisms
The Three Domains The diversity of life can be arranged into three domains:
Ø Archaea
Ø Bacteria
Ø Eukarya