CHAPTER 1Biology Introduction

WHY BIOLOGY? Understand your world Make informed decisions

SelfFamilyMedicalDiet

Make informed votes Understand significance of

accomplishments

DEFINITION Bios = life ology = study of

Biology = study of life

LIVING THINGS HAVE…. Organization

Atom

Molecule

Cell

Tissue

Organ

Organ system

LIVING THINGS HAVE…. Organization (cont.)

Multicelled organism

Population

Community

Ecosystem

Biosphere

LIVING THINGS MUST… Acquire energy

AutotrophsHeterorophs

Metabolize

Maintain homeostasis

LIVING THINGS MUST…. Grow

Reproduce

Respond

Adapt

CLASSIFICATION Taxonomy—ID and organize into logical

groups Nomenclature—name organisms

Binomial nomenclature (Genus, species)Homo sapiensCanis lupusFelis concolor

HIERARCHY OF CLASSIFICATION Domain Eukarya Kingdom Animalia Phylum Arthropoda Class Insecta Order Lepidoptera Family Danaidae Genus Danaus Species plexippus

Monarch Butterfly

DOMAINS Eubacteria Archaebacteria Eukarya

Kingdom ProtistaKingdom FungiKingdom PlantaeKingdom Animalia

SCIENTIFIC METHOD Gather information about the world Do it objectively Explain the natural world using rules or

patterns in the natural world Explanations that are testable Can use information for prediction No conclusion drawn in science is final!

However, can say many things with high probability

SCIENTIFIC METHOD Observation Hypothesis Test Analyze & Interpret Repeat Theory

EXPERIMENTAL DESIGN Control Group

Standard of Comparison Identical to testing group other than the

variable being tested Sampling Error

Certain amount of error in any studyTry to minimize by taking large sample sizes

EXPERIMENT… Observation: Some students fall asleep in Dr. Bern’s class Hypothesis: Dr. Bern is the most boring Biology instructor Test: Count number of sleeping students in Dr. Bern’s and

Mr. Harnden’s classes Results: 3/48 Students sleeping in Dr. Bern’s class, 4/48

students sleeping in Mr. Harnden’s class Repeat: Count sleeping students in Dr. Bern’s and Ms.

Henderson’s classes Results: 3/48 students sleeping in Dr. Bern’s class, 2/48

students sleeping in Ms. Henderson’s Analysis: 4% of students sleep in Ms. Henderson’s class, 6%

in Dr. Bern’s, 8% in Mr. Harnden’s. There is a 3% margin of error.

Conclusion: Student’s sleep in Dr. Bern’s class at the same rate as other Biology instructors

Theory: Whether or not students fall asleep in class doesn’t depend on the instructor

BIOLOGICAL THERAPY EXPERIMENTS

Can we use viruses that attack bacteria (bacteriophages) to fight infections?

EXPERIMENT 1 Hypothesis - Bacteriophages can protect

mice against infectious bacteria

Prediction - Mice injected with bacteriophages will not die as a result of bacterial injection

EXPERIMENT 1—TEST

Experimental group Inject with bacteria and bacteriophage

Control group Inject with bacteria and saline

EXPERIMENT 1—RESULTS & CONCLUSION Experimental group

All mice lived Control group

All mice died Conclusion - Bacteriophage injections

protect mice against bacterial infections

EXPERIMENT 2 Prediction - Bacteriophage injections will

be more effective treatment than single dose of the antibiotic streptomycin

Test - Mice injected with bacteria, then with saline, streptomycin, or bacteriophage

EXPERIMENT 2—RESULTS With 2nd injection:

Bacteriophage - 11 of 12 mice lived60 mg/gm streptomycin - 5 of 12 lived100 mg/gm streptomycin - 3 of 12 livedSaline - all mice died

Conclusion - Bacteriophage treatment can be as good or better than antibiotic

LIMITATIONS Limited to our knowledge and

understanding of the natural world Cannot answer philosophical, moral, or

ethical questions Limited by man’s falibility