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
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