1.+the+process+of+science,+bio+101+fall+2014

What is Life?
Biology, Science, and How we Study
Things.

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. Organized
2. Uses energy
3. Maintains internal environment
4. Reproduces
5. Responds to the Environment
6. Grows, and develops
7. 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

Properties of Life: Reproduction
Figure 1.5 Asexual and Sexual 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
Producer
Consumer
Decomposer

Simple Food Web
Producers extract
energy
and nutrients from the
nonliving environment
Consumers obtain
energy and nutrients by
eating other organisms.
Decomposers are consumers
that obtain nutrients from dead
organisms and organic wastes.

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: Natural Selection in
Bacteria
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Generation1 Generation2 Multiple generations later
Staphylococcus aureus
a. SEM (false color) 10 μm b.
before mutation
Antibiotic-resistant bacteria
are most successful
Mutation
occurs (red)
Time
Antibiotic present
Time
Reproduction
and
Selection
a (left): © Dennis Kunkel Microscopy, Inc.; a (inset): © Ron Occalea/ The Medical File/Peter Arnold/Photolibrary
Hair
Bacterial
cell

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

1.+the+process+of+science,+bio+101+fall+2014

Tree of Life - Bacteria
DOMAIN BACTERIA
• Cells lack nuclei (prokaryotic)
• Unicellular

Tree of Life Archaea
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
DOMAIN ARCHAEA
• Cells lack nuclei (prokaryotic)
• Unicellular

Tree of Life Eukarya
DOMAIN EUKARYA
• Cells contain nuclei (eukaryotic)
• Unicellular or multicellular
Kingdom Animalia
• Multicellular
• Heterotrophs (by ingestion)
LM 200 μm
Kingdom Fungi Kingdom Plantae
• Most are multicellular
• Multicellular
• Heterotrophs (by external
• Autotrophs
digestion)
Protista (multiple kingdoms)
• Unicellular or multicellular
• Autotrophs or heterotrophs

Scientific Method
• Sir Frances Bacon: the 1st to document the
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 shoreline
Impact 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.

Experimental Design: removed colorful plumage
None trimmed (control) All
trimmed (control)
½ trimmed (experimental)

Data: Measured weight and survival of the chicks
CONCLUSIONS?

Basic vs. Applied Science
• Basic: “pure science,” gain knowledge
• Applied: “technology,” solve real-world
problems

1.+the+process+of+science,+bio+101+fall+2014

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