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Chapter 1: Biology
Exploring Life
Biology Defined
 Biology


– study of living organisms
Consider the diversity of characteristics
among the many living organisms you know.
Yet all share underlying properties
• Our focus for the semester
Levels of Organization (1.2)
 In
studying nature patterns arise
 Biologists organize nature from the
simplest level to the most inclusive level

page 3
Biosphere
Ecosystem
Community
Population
Organism
Organ System*
Organ*
Tissue*
Cell
Organelle**
Molecule
Atom
*apply to multi-celled organisms only
** eukaryotes only
Levels of Organization
Atom

Smallest particle of an element that has
the properties of the element
Levels of Organization
 Molecule

Group of atoms
joined by chemical
bonds
Levels of Organization
 Organelle

Membrane bound
structure within a
eukaryotic cell that
performs a specific
function
Mitochondria – metabolizes
glucose to make energy for
eukaryotic cells
Levels of Organization
Cell – smallest unit
that can live and
reproduce on its
own
Prokaryotic cells
- No nucleus, smaller
Eukaryotic cell
-Has a nucleus
-Larger, more complex
Levels of Organization
 Tissue

Organized group
of cells and
substances that
interact to serve
a function
• Multi-celled
organism only
Muscle Tissue
Levels of Organization
 Organ

2 or more tissues working together to
serve a function
• Multi-celled
organism only
Heart – pumps blood to
lungs and body
Levels of Organization
 Organ

System
Group of organs
working together
to perform a
function
• Multi-celled
organism only
Cardiovascular System
Levels of Organization
 Organism

An individual
living thing
Single-celled Organisms
bacteria
Multi-celled Organism
Blue shark
Levels of Organization
 Population

All organisms of the same species
inhabiting a given area
Population of sunflowers
Population of cormorants
Levels of Organization
 Community

All populations of living organisms
inhabiting a given area
 Ecosystem

All the living organisms in a given area
and their physical environment
Identify the:
Ecosytem
Community
Population(s)
Red Fish
Levels of Organization
 Biosphere

All regions of the
Earth that support
life
• most inclusive and
complex level
Biosphere
Ecosystem
Community
Population
Organism
Organ System*
Organ*
Tissue*
Cell
Organelle**
Molecule
Atom
*apply to multi-celled organisms only
** eukaryotes only
Organisms and the Ecosystem
(1.4)
 Organisms
interact with the other
organisms and the nonliving in the
environment
 Each organism plays a role in the
ecosystem


Producer
Consumer
• Decomposer
Producers
 Producers
provide food for an
ecosystem
• Plants use the sun’s energy, CO2 and H2O
to make sugars and oxygen in a process
called photosynthesis
• Also interact with the soil - absorbing
nutrients and breaking up particles
Producers
 Producers

are also known as autotrophs
Producers are all capable of photosyntheis
and include:
• Plants
• photosynthetic bacteria and protists
Consumers
 Consumers
obtain their food by
eating plants or other animals
• All take in O2 and release CO2
• Their wastes return substances into the
environment

Consumers are also known as heterotrophs
• Animals and others are consumers
Decomposers
 Decomposers
break down wastes and
remains of other organisms to simpler
substances that plants can use
• Decomposers recycle nutrients.
• Decomposers are heterotrophs
• Examples: Fungus, small animals, and
some bacteria are decomposers.
Sun
Air
Inflow
of
light
energy
O2
CO2
CO2
O2
Chemical
energy
Producers
Cycling of
chemical
nutrients
Consumers
Decomposers
H2O
Soil
Ecosystem
Loss
of
heat
energy
Flow of Energy and Nutrients

In every ecosystem there is a:


Recycling of nutrients
• Plants  consumers  decomposers  plants ….
One way flow of energy
• From sun  producers  consumers  decomposers
heat
heat
heat
• As energy is transferred between living organisms
some of the energy is always “lost” to the
environment in the form of heat

See page 5
Cells (1.3)

The cell is the smallest structure that
exhibits all of the properties associated
with life
Two types of cells
1. Prokaryotic cells
2. Eukaryotic cells
Cells
Prokaryotic Cells
Simpler
-- no nucleus
-- no organelles
Smaller
Examples - Bacteria
Eukaryotic Cells
More complex
--DNA enclosed in a
membrane, called a
nucleus
-- organelles present
Larger
Examples: Animals,
plants, fungus, protists
Cells as Systems
– combination of simpler
components that form a more complex
organization
 System

Cells are a system with emergent properties
• properties that emerge as a result of the
arrangement and organization of the components
Properties Common to all Living
Organisms (1.1 , 1.3)
 All
living organisms share a number of
characteristics.

We will consider 7 of these.
• First property slightly modified from text.
• Order the properties are presented in lecture
differs from that in the text.
All living organisms:
1). are made up of one or more cells.
•
All cells are made of the same
substances arranged in the same
basic ways.
• Cells structure is an example of the high
level of order observed in living organisms
All living organisms:
2) Grow and develop as directed by
their DNA
•
Molecular code in DNA gives
directions for building proteins
• The proteins an organism makes
determines the characteristics of the
organism
All living organisms:
Grow and develop as directed by their
DNA,continued…..


Flow of information in the cell is from
• DNA  RNA  Protein
An organism’s DNA determines which RNAs
are made and thus which proteins are made
at any given time
All living organisms
3). Reproduce their own kind

Living organisms pass their DNA on to
their offspring
Only living organisms:
4). Take in energy and transform it to
perform life’s activities

Require an input of energy to grow, maintain
themselves, and reproduce.
• called metabolism.
All living organisms:
5) Regulate their internal environment
in an effort to maintain homeostasis.

Homeostasis – ability to maintain the
internal environment within ranges
tolerable for life
• Insulin and blood sugar example
All living organisms
6). Respond to their environment

Living organisms sense and make
controlled responses to changes in the
environment.
• Temperature and sweating example
All living organisms
7). Have the capacity to evolve over
time

Organisms with characteristics that
improve their odds of survival or
reproduction pass their DNA on more
often  results in evolution
All living organisms:
1.
Made up of one or more cells (order)
2.
Grow and develop based on instructions in
DNA
3.
Reproduce their own kind
4.
Engage in metabolism – energy processing
5.
Regulate their internal environment
6.
Respond to the environment
7.
Have the capacity to evolve.
Classifying the Diversity (1.6)
 Each
living organism can classified by a
two part name: Genus species

Taxonomy – field in biology that identifies and
classifies organisms
Examples:


Homo sapiens (humans)
Lamna nasus (porbeagle shark)
Classification Scheme
Domain – most inclusive (3)
Kingdom – related phlya (6 ?)
Phylum – related classes
Class – related orders
Order – related families
Family – related genera
Genus species - defines the organism
(also called species)
Classification of a Mako Shark
Domain - Eukarya
Kingdom – Animalia
Phylum – Chordates (spinal cord)
Class – Chondrichthyes (cartilaginous fish)
Order – Lamniformes (5 gill slits….)
Family – Lamnidae
Genus – Isurus
Species – oxyrinchus
FYI slide – not for test
H. sapiens & Isurus oxyrinchus !
Classifying the Diversity
Classify organisms into one of 3 Domains:
1.
Bacteria
2.
Archae(bacteria)
3.
Eukarya
•
•
•
•
Protists
Fungus
Plants
Animals
Protista
Plants
Fungi
Animals
Eukaryotes
Archaebacteria
Eubacteria
Prokaryotes
Origin of life
Domains?
Kingdoms?
Cell Types?
Domain (Kingdom) Bacteria
Cell type: prokaryote

Lack a nucleus and
organelles
Cell Size: small

~1-10 microns
Single celled organisms
Ubiquitous
Domain (Kingdom) Archae
Cell type: prokaryote
Cell Size: small
Single celled
Many are extremophiles live in extreme
environments
Domain - Eukarya
 All
organisms with eukaryotic cells are
placed in the domain Eukarya

Eukaryotic cells have:
1.
2.
 Within
this domain are 4 major Kingdoms.
Kingdom - Protista
Cell type: Eukaryote


More complex cell with a
nucleus and organelles
Cells are larger than
bacterial cells
Primarily single celled,
some multi-celled
Autotroph or heterotroph
Examples: Euglena,
paramecium, ameoba
Kingdom - Fungi
Cell type: Eukaryote
Single or multicelled
Heterotrophs
decomposers with
external stomachs
Examples: yeast,
mushrooms, molds
Kingdom - Plantae
Cell type: Eukaryotic
cells with cell walls
Multicelled organisms
Producers

Photosynthetic
Examples:
Kingdom - Animalia
Cell type: eukaryote

(no cell walls)
Multicelled organisms
Consumer/heterotroph
Most are mobile at
some time in life
Theory of Evolution (1.7)
 Evolutionary
Theory was proposed by
Charles Darwin in 1859. He proposed:
• Species present today descended with
modifications from ancestral species
(evolution)
• Proposed that evolution occurs as a result
of natural selection
1831 HMS Beagle: Darwin visits the Galapagos
Noticed different traits among similar species
Great
Britain
Europe
Asia
North
America
PACIFIC
OCEAN
The
Galápagos
Islands
PACIFIC
OCEAN
Pinta
Marchena
Pinzón
Isabela
0
0
40 km
Equator
Daphne
Islands
Santa Santa
Cruz Fe
Florenza
40 miles
Africa
San
Cristobal
Española
PACIFIC
OCEAN
Equator
South
America
Genovesa
Santiago
Fernandina
ATLANTIC
OCEAN
Australia
Cape of
Good Hope
Cape Horn
Tierra del Fuego
Tasmania
New
Zealand
On dry islands,
long neck for
taller plants
On wet islands,
short neck for
lower vegetation
Darwin observed
1.
Individuals within a population vary in traits
•
2.
Many of those traits are heritable
The population has the potential to produce
more offspring than will survive to reproduce
 Darwin


proposed:
Variation leads to unequal reproductive
success
• Some variations in traits impact survival
and reproduction rates
• Those with heritable traits best suited to the
environment produce more offspring
Over time the favorable traits become more
common in the population = evolution by
natural selection
Put simply…Darwin proposed…..


Those individuals with heritable traits that
increase their odds of surviving and
reproducing produce the greatest number of
viable offspring
• Called Natural Selection
The favorable traits become more common
over time => results in evolution
Natural Selection
Key Terms
Evolution
 genetically based change in a line of descent
• Occurs as a result of natural selection
Natural Selection
 outcome of differences in survival and
reproduction among individuals that vary in
traits
Key Terms
Adaptive Trait
 any form of a trait that gives an individual an
advantage in surviving and reproducing under
a given set of conditions
What’s the source of the variation?
1.
Sexual reproduction – creates new
combinations of DNA
– New DNA combinations may give an
organism a reproductive/survival
advantage
2.
Mutations – create new versions of
DNA  new proteins  new traits

Mutations may be harmless, harmful, or
beneficial
Skin color impacts the
survival/reproduction of
snakes in the wild.
Which snake is more likely to
survive and reproduce in the wild?
Which will be naturally selected for?
UMA’s resident mutant
The variation in feather color
does not appear to impact this
crow’s ability to survive.
You tell me….
 The
antelope on the next slide have a 2
month gestation period.
 Newborn antelope can walk/run at birth.
 Their population is growing in spite of an
abundance of predators in the area.
 Relate these facts to evolutionary theory.
Herd of Impala
Methods of Science - Lab
How do scientists learn about the natural
world?


Discovery science – attempts to describe
nature
•
•

Darwin’s work as a naturalist
Human genome project
Hypothesis-based science – attempts to
explain nature
•
Experiment based
Hypothesis-based Science
 The
scientific method describes a
framework by which hypothesis-based
science is conducted.


Scientific method has been described as
organized common sense.
Methodical approach to problem-solving.
Scientific Inquiry
Observations
Questions
Develop hypotheses to explain observations or
answer questions
Make predictions
1.
2.
3.
4.

Make predictions, if hypothesis is true then….
Test hypotheses
5.


Test accuracy of the prediction for each
hypothesis…
Analyze results and share findings and conclusions
Observations & Hypothesis
 Observations
must be recordable and
repeatable
– tentative explanation of
observations
 Hypothesis

Supported by limited data
From Hypothesis to Experiments
 Use
deductive reasoning to make a
prediction based on the hypothesis

If the hypothesis is true what else will be true?
 Test
that prediction under controlled
conditions
Testing the Prediction/Hypothesis
 Set
up a control group as a standard for
comparison

Identical to experimental group except for the
variable being studied
• Easier said than done with human research!
Interpreting Results
 Outcome
of the experiment(s) will either
support or disprove the hypothesis



Never prove a hypothesis is 100% correct!
Always alternate hypotheses.
A hypothesis gains credibility when many
experiments fail to disprove it.
Scientific Theory
A
hypothesis is elevated to a scientific
theory when it is supported by a significant
amount of data and it explains a broad
range of observations


Theories are subject to rigorous testing and revision
when needed
Darwin’s theory of evolution by natural selection
is an example of a theory
Limits of Science
 Scientific
approach cannot address moral,
aesthetic, or philosophical issues
 Limited
by the technologies and methods
of the day

By what can be observed/recorded