1.+the+process+of+science,+bio+101+fall+2014
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Biology lecture pptsTRANSCRIPT
What is Life?
Biology, Science, and How we Study Things.
What is Science
What is Life?
• Biology is the scientific study of life
• Define life by listing basic components– Cell is basic unit of life– Every organism is one or
more cells– DNA used to produce
proteins
Figure 1.1 Informational Molecule of Life.
Properties of Life
1. Organized2. Uses energy3. Maintains internal environment4. Reproduces5. Responds to the Environment6. Grows, and develops7. Evolves
Properties of Life
1) Order 2) Reproduction 3) Growth & Development
4) Energy Processing 5) Response to the Environment 6) Regulation
7) Evolutionary Adaptation
Properties of Life: Order
• Life has order and energy is required to maintain this order
1) Order
Properties of Life: Reproduction
• Life Reproduces Itself, Grows, and Develops– Asexual reproduction
• All offspring identical
– Sexual reproduction• Offspring have new combination of traits
– Growth and development
Figure 1.5 Asexual and Sexual Reproduction.
Properties of Life: Reproduction
Properties of Life: Growth and Development
• Grow and Develop – cell division and specialization until maturity
Properties of Life: Energy
• Every living thing needs energy to live– Metabolism – sum of the chemical reactions in an organisms
that produce and use energy• Living things classified by how get energy
– Producers – Autotrophs, make own food from nutrients and non-living sources (sun)
– Consumer – Heterotroph, get energy by consuming other organisms (dead or alive)
– Decomposer – Heterotroph, get energy from dead organisms or wastes
• All types of organisms live together in ecosystem and make a food web
Properties of Life: Energy
ProducerConsumer
Decomposer
Simple Food Web
Producers extract energyand nutrients from thenonliving environment
Consumers obtainenergy and nutrients byeating other organisms.
Decomposers are consumersthat obtain nutrients from deadorganisms and organic wastes.
Properties of Life: Energy
Properties of Life Energy
Properties of Life: Respond to Environment
• Life can sense and react to stimuli• To do this, cells have to be in constant
environment (relatively!)
Properties of Life: Regulation/Homeostasis
• Homeostasis – Process by which cell or organisms maintains a state of internal constancy or EQUILIBRIUM
• Ex. Your internal temperature is 37⁰C or 98.6⁰F
Properties of Life/Adaptation
• How life changes over time to become best suited to its environment– Adaptation – Inherited trait that make organisms
better suited to environment • Better survival• More successful reproduction
– Natural Selection – Through adaptation, a set of traits that make one organism more successful than another
• Enhanced reproductive success leading to more individuals
Properties of Life/Adaptation
Properties of Life: Natural Selection in Bacteria
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a. b.SEM (false color) 10 µm
Staphylococcus aureusbefore mutation
Generation1 Generation2 Multiple generations later
Antibiotic-resistant bacteriaare most successful
Mutationoccurs (red)
Time
Antibiotic present
Time
Reproductionand
Selection
a (left): © Dennis Kunkel Microscopy, Inc.; a (inset): © Ron Occalea/ The Medical File/Peter Arnold/Photolibrary
Hair
Bacterialcell
Properties of Life: Natural Selection in Bacteria
Life is Organized• Atoms• Molecules• Organelles• Cells• Tissues• Organs• Organ Systems• Organisms• Population • Community• Ecosystem• Biosphere
• Emergent Properties– Interacting properties
that give an organisms a complex function
– Change the structure, change the function
– Interrupt the function too much, structure breaks down
ATOM: The smallest chemical unit of a type of pure substance (element).Example: Lithium atom
MOLECULE: A group of joined atoms.Example: DNA
ORGANELLE: A membrane-bounded structure that has a specific function within a cell.Example: Chloroplast
CELL: The fundamental unit of life. Example: Leaf cell
TISSUE: A collection of specialized cells that function in a coordinated fashion.Example: Epidermis of leaf
ORGAN: A structure consisting of tissues organized to interact and carry out specific functions.Example: Leaf
COMMUNITY: All populations that occupy the same region.Example: All populations in a savanna
ECOSYSTEM: The living and nonliving components of an area.Example: The savanna
BIOSPHERE: The global ecosystem; the parts of the planet and its atmosphere where life is possible.
ORGANISM: A single living individual.Example: One tree
ORGAN SYSTEM: Organs connected physically or chemically that function together.Example: Aboveground part of a plant
POPULATION: A group of the same species of organism living in the same place and time.Example: Multiple acacia trees
Organization of Life
Tree of Life - Bacteria
• Cells lack nuclei (prokaryotic)• Unicellular
DOMAIN BACTERIA
Tree of Life ArchaeaCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Cells lack nuclei (prokaryotic)• Unicellular
DOMAIN ARCHAEA
Tree of Life Eukarya
• Cells contain nuclei (eukaryotic)• Unicellular or multicellular
DOMAIN EUKARYA
Kingdom Animalia
• Multicellular• Heterotrophs (by ingestion)
LM 200 µm
Kingdom Fungi Kingdom Plantae
• Most are multicellular• Heterotrophs (by external digestion)
• Multicellular• Autotrophs
Protista (multiple kingdoms)
• Unicellular or multicellular• Autotrophs or heterotrophs
Scientific Method
• Sir Frances Bacon: the 1st to document the scientific method
Scientific Method
Experimental Design
• Used to test hypotheses– Can be controlled (in a lab) or in the natural environment
• What you need to consider– Sample size – How many individuals or observations do you
have to make– Variables – What can change in your experiment
• Independent Variable – The thing you change• Dependent Variable – The response• Standardized Variable – Constant
– Control – Provides basis for comparison– Statistical Analysis – Math using your data to prove or or
disprove your hypotheses
Sample Experiment
Observations – Fish community looks different when you change the shoreline
Hypothesis – A change in shoreline structure will change the fish community
Data Collection – Seine sampling to collect fish at sites
Sample Size – Measure 10 fish per species, total count, total biomass of all fish in each haul
Control –Control Sites – those with no change in shorelineImpact Sites – those with shoreline change
Data Analysis – Metrics (diversity, species richness, biomass), Statistical analysis
Theory – Based on data, the fish community is different at control sites than impact sites
Case Study on the Scientific Method
Question: Why do baby coots have ornamental plumage during the first three weeks of life?
Hypothesis: Bright ornamental plumage makes the chicks more attractive to the parents and increases survival
Prediction: If the hypothesis is supported, then removing the ornamental plumage will decrease survival (and body weight) of the chicks.
Case Study on the Scientific Method
Experimental Design: removed colorful plumage
None trimmed (control) All trimmed (control)
½ trimmed (experimental)
Case Study on the Scientific Method
Data: Measured weight and survival of the chicks
CONCLUSIONS?
Basic vs. Applied Science
• Basic: “pure science,” gain knowledge• Applied: “technology,” solve real-world
problems