BIOLOGY: EXPLORING LIFEChapter 1

Why Biology?• Inquiry stems from natural curiosity about

the world around us– Limited by what we can observe and measure

• Biology is the study of life– Understand your world– Make informed decisions– Understand significance of accomplishments

Duck-billed platypus

Mimicry

Swine flu virus

Global warming

The Case of the Missing Socks:A Case Study of the Scientific Process

• Observation(s)– Natural phenomena detected by senses– Must be testable, reproducible, and falsifiable

• Hypothesis– Educated guess to explain observation(s)– If … then statements

• Testing/experimentation– Doesn’t prove correct, but not wrong– Requires: control and experimental groups, independent and dependent variables

• Analysis/interpretation– Partial support– No support– Does support

• Repetition– Larger samples– Change variables– Other scientists repeat results

• Theory– Tested many times, but not yet disproved

Limits to the Scientific Process

• No absolute truths

• Can’t address supernatural phenomena

• Limited by current knowledge and understanding

• Can’t answer moral or ethical questions

• Limited by our fallibility

Life Emerges As A Hierarchy

• Emergent properties– Novel properties with

each progression in the hierarchy

• Reductionism– Reducing complex systems

into simpler parts– Limited because life is an

emergent property

Organelles

Life Interacts in the Environment

• Multiple roles– Producers– Consumers– Decomposers

• 2 major processes– Transfer of nutrients– Transfer of energy

• Some lost as heat

Cells are the Basic Units of LifeProkaryotic Cell

• Smaller, less complex• No nucleus or membrane bound

organelles• Bacteria

Eukaryotic Cell

• Larger, more complex• Nucleus and membrane bound

organelles• Plants, animals, and fungi

Basics of All Cells

• All cells have DNA (deoxyribonucleic acid)– Inherited from parents– Directs proteins, the building blocks of life

• Arrangement determines function– Similar to alphabet– Contributes to the diversity of life

• All life forms use the same basic code– Can artificially create instructions when necessary

Characteristics that Define Life

• All living things …– Have organization– Regulate themselves– Metabolize– Grow– Reproduce– Respond– Adapt

• Limitations exist

Classifying Living Things

• Life can have multiple types– Cats, fish, birds, trees, and bacteria

• Taxonomy sorts and classifies– Nomenclature to identifiy specific organisms– Developed by Carolus Linnaeus

• Binomial system- two parts to organisms name (Genus species)– Panthera pardus– Panthera leo– Panthera tigris– Homo sapiens– Canis familiaris– Canis lupus

Taxonomic Hierarchy

DifferentKillerPenguinsCrawlOverFrozenGlacialShores

Subheadings exist for all taxons

Domains

• Bacteria– Prokaryotes– Most diverse and wide

spread– Most are singled-celled

• Archaea– Prokaryotes– Live in extreme

environments (extremophiles)

• Eukarya– Eukaryotes

• Multiple kingdoms– Have a nucleus and

membrane bound organelles

The Theory of Evolution

• On the Origin of the Species by Means of Natural Selection, 1859

• “Descent with Modification”– Evolution of ancestors into current

species

• Occurs through natural selection– Unequal reproductive fitness, not

“survival of the fittest”– Facilitates evolutionary adaptation

Examples of Selection

• Natural selection– Peppered moth

• Pre- and post-industrial England• Populations of light and dark moths changed

– Antibiotic resistance• Importance of taking as prescribed and when necessary• Beta-lactams (penicillin and amoxicillin) are common

examples

• Artificial selection– Hybrid dogs

• Humans are agents• Chosen for specific traits

Labradoodle

Types of Selection

Natural Selection• Peppered moth• Antibiotic resistance

– Kill some bacteria, but not all• Resistant survive &

reproduce• Proportion of antibiotic-

resistant bacteria increase– Importance of taking

antibiotics as perscribed– Importance of only taking

when necessary– E.g. Penicillin, amoxicillin, etc.

Artificial Selection• Vegetables• Hybrid dogs

– Humans are agents

• Dog breeds• Human mating

Science and Technology• Goals

– Science = understand natural phenomenas; create discoveries

– Technology = apply science for a purpose; create inventions• Mutualistic relationship

– Scientific discoveries lead to new technology development while technology helps scientists in research

• Pros vs Cons– Advances in technology vs environmental effects– How much information is too much?

• Need for everyone to have a level of scientific knowledge so they can make informed decisions