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Chapter 1
Exploring Life
1. Define biology
2.
3.
4.
5.
Define living
Scientific Inquiry
Biological Hierarchy
Biological Themes
What is Biology?
Definition
Scientific study of LIFE
What is Living?

To be classified as living, these
criteria must be met:
1. Highly ordered structure
2. Evolutionary adaptation
3. Respond to environment
What is living?
4. Regulation of internal functions
* Homeostasis
5. Process energy
6. Grow & Development
7. Reproduce
* Hereditary Material
Is a virus living?

Why or Why not?
How is Biology Studied?
Science (“to know”)
Includes
1. Body of knowledge
2. Scientific Inquiry process
Search for information & explanation
focus on specific questions
Scientific Inquiry

Two types
1. Discovery science
Describe natural processes
Observation
Inductive Reasoning (generalizations from
specific observations)
“All organisms are made of cells”
Scientific Inquiry
2. Hypothesis-based science
Focus on explanations
*Hypothesis
Deductive Reasoning
general to specific
if ---> then
“if all organisms are made of cells,
then humans are composed of cells”
Observations
Questions
Hypothesis # 1:
Dead batteries
Prediction:
Replacing batteries
will fix problem
Test prediction
Figure 1.25
Test falsifies hypothesis
Hypothesis # 2:
Burnt-out bulb
Prediction:
Replacing bulb
will fix problem
Test prediction
Test does not falsify hypothesis
Hypothesis-Based Science
Idealized Scientific Method
1.
2.
3.
4.
5.
Observation
Question
Hypothesis
Experiment
Conclusion
Scientific Method
1.
2.
3.
4.
5.
Must be testable
Must be falsifiable
Experiments must be repeatable
Control effects of unwanted variables
Supernatural phenomena is not
addressed
Data
Two types of recorded observations
1. Quantitative
2. Qualitative
Figure 1.24
Hierarchy of Biology

Levels of Organization
1. Molecules
2. Organelles
subcellular, specific functions
3. Cells
Hierarchy of Biology
4. Tissues
5. Organs
6. Organ System
Hierarchy of Biology
7.
8.
9.
Organism
Population
Community
Hierarchy of Biology


10. Ecosystem
11. Biosphere
1 The biosphere

From the biosphere to organisms
Figure 1.3
9 Organelles
1 µm
Cell
8 Cells
Atoms
10 µm
7 Tissues
50 µm
6 Organs and organ systems
Figure 1.3
10 Molecules
Themes
of
Biology
Table 1.1
Themes of Biology
1.
Cell
Basic unit of life
smallest unit that can perform all
activities of life
Figure 1.5
25 µm
Two Cell Types
1. Prokaryotic
no membrane bound nucleus
no membrane bound organelles
primarily bacteria
Two cell types
2. Eukaryotic
membrane bound nucleus
several membrane bound organelles
ex. Protists, fungi, plants, animals
re 1.8
EUKARYOTIC CELL
PROKARYOTIC CELL
DNA
(no nucleus)
Membrane
Membrane
Cytoplasm
Organelles
Nucleus (contains DNA)
1 µm
Themes of Biology
2.
DNA is heritable information
allows for continuity of
life by transmitting
biological information
Nucleus
DNA
Cell
Nucleotide
(a) DNA double helix. This model shows
each atom in a segment of DNA.Made
up of two long chains of building
A
C
T
A
T
A
C
C
G
T
A
G
T
A
(b) Single strand of DNA.
letters are simple symbo
small section of one chai
Themes of Biology
3.
Emergent properties
refers to unique, new property of each hierarchy
level not present at the simpler level
Themes of Biology
4.
Feedback Regulation
kind of supply and demand economy
regulate production of enzymes, proteins
Two types:
1. Negative feedback (product turns it off)
2. Positive feedback (product speeds it up)
Negative Feedback
A
Negative
feedback
Enzyme 1
B
A
Enzyme 1
B
Enzyme 2
C
C
Enzyme 3
D
D
Figure 1.11
D
D
D
D
D
D
D
D
D
Positive Feedback
W
W
Enzyme 4
Enzyme 4
Positive
feedback
X
X
Enzyme 5
Enzyme 5
Y
Y
Enzyme 6
Z
Z
Z
Z
Z
Z
Z
Z
Figure 1.12
Enzyme 6
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Themes of Biology
5.
Interaction with environment
interactions
abiotic factors
biotic factors
6.
Energy and life
Organisms must perform work
Energy flow
Themes of Biology
7.
Unity in the
Diversity
of Life
15 µm
1.0 µm
Cilia of Paramecium.
The cilia of Paramecium
propel the cell through
pond water.
5 µm
Figure 1.16
Cross section of cilium, as viewed
with an electron microscope
Cilia of windpipe cells. The cells that line the human windpipe
are equipped with cilia that help keep the lungs clean by moving
a film of debris-trapping mucus upward.
Paradox of Unity &
Diversity
Unity
1. DNA is the genetic, heritable
material, universal genetic code
2. Universal processes
Replication, Transcription,
Translation
Paradox of Unity &
Diversity
Diversity
vast collection of living organisms on
Earth
categorized into levels based on similarities
Classifying Life

Taxonomy – branch of bio that names and
classifies species
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Classifying Life

3 Domains
1. Bacteria - prokaryotes
2. Archaea - prokaryotes
3. Eukarya - eukaryotes
Bacteria are the most diverse
4 µm
and widespread prokaryotes
and are now divided among multiple
kingdoms. Each of the rod-shaped
structures in this photo is a bacterial cell.
DOMAIN ARCHAEA
Figure 1.15
Many of the prokaryotes known
0.5 µm
as archaea live in Earth‘s
extreme environments, such as salty lakes
and boiling hot springs. Domain Archaea
includes multiple kingdoms. The photo
shows a colony composed of many cells.
Protists (multiple kingdoms)
100 µm
are unicellular eukaryotes and
their relatively simple multicellular
relatives.Pictured here is an assortment of
protists inhabiting pond water. Scientists are
currently debating how to split the protists
into several kingdoms that better represent
evolution and diversity.
Kingdom Plantae consists of
multicellula eukaryotes that carry
out photosynthesis, the conversion
of light energy to food.
Kindom Fungi is defined in part by the
nutritional mode of its members, such
as this mushroom, which absorb
nutrientsafter decomposing organic
material.
Kindom Animalia consists of
multicellular eukaryotes that
ingest other organisms.
Themes of Biology
8.
Evolution
accounts for diversity based on life’s unity
Charles
Darwin
Figure 1.18
Evolution

Charles Darwin in The Origin of
Species articulated two main points:
1. Descent with modification
2. Natural selection
Themes of Biology
9.
Structure & Function –
everything has
purpose at all biological levels
10.
Scientific Inquiry
11.
Science, Technology, & Society –
applications of science & production of
technologies to benefit society