Biology
101 Chapter 1
The Scientific Study of Life
Biology
= the study of living things and their interactions.
Bio – life
logy – study of
1.1
Life’s Levels of Organization
Molecular
Cellular
Tissues
Organs
Organ Systems
Organism
Population
Community
Ecosystem
*This
order represent life’s hierarchy of complexity
1.2
The Scientific Method
-
Investigative process of studying the natural world
Steps:
1)
Observations:
objective, quantitative, many forms
2)
Questions
3)
Hypotheses:
tentative explanations that attempt to answer the questions
4)
Predictions:
deductive reasoning to predict the results if hypothesis is correct,
“If…..then” logic
5)
Tests:
experimentation
6)
Revision:
either accept present hypothesis or revise it.
Re-test
The
scientific process also is:
·
a
cyclic process
·
involves
critical thinking at every step
·
is
cumulative
·
can
support or falsify a hypothesis
A
word on “Hypothesis”!
·
Must
be testable
·
Must
be falsifiable
·
And
is never proven absolutely true
What
is a Theory?
A hypothesis that has survived rigorous
testing, is widely accepted, has a broad scope, and is supported by a large
body of evidence.
Ex.
Theory of Evolution
What
is a Law?
A widely accepted principle that makes
predictions but has no explanatory power.
Ex.
Laws of Thermodynamics
1.4
Evolution, Unity and Diversity
Some features of living
organisms are determined by ENVIRONMENT.
Others are determined by HEREDITY.
Life is very diverse = >2
million species
Ex.
plasmodium slime mold – grizzly bear
How many students in this
class have heard of the French Impressionist painter Monet? Art students who are familiar with Monet’s
work can probably pick out a Monet painting from a gallery of different
paintings, because of the unity of
theme and style in his work. Each Monet
painting is unique in its subject and effect, in other words, there is a
tremendous diversity in his paintings.
Yet there is also a stylistic unity.
In Monet’s work, there is unity in the midst of diversity.
Life
is unified in a hierarchical classification
Domain
Kingdom
Phylum/Division
Class
Order
Family
Genus
Species
3
Domains:
1) Archaea
2) Bacteria
3) Eukarya
5
Major Kingdoms
1) Monera
= bacteria
2) Protista = algae and protozoans
3) Fungi
= molds, yeast, mushrooms
4) Plantae = plants
5) Animalia = animals
What
is life? What distinguishes life from
non-life? What unifies life?
1.5
Characteristics of Life
1.
Order
2.
Regulation
3.
Growth
and Development
4.
Energy
Utilization
5.
Responsiveness
6.
Reproduction
1.6
Evolution as a Unifying Theme of Life
-
evolution
explains the unity of life
-
Evolution
= genetic (heritable) changes in a population or species over generations. All life is evolving.
-
Charles
Darwin:
·
born
in 1809
·
in
1831 began a round-the-world voyage at age 22 on board the H.M.S. Beagle as a naturalist
·
1859
published “On the Origin of Species”
·
proposed
a mechanism for evolution
-
Evolution
vs. Spontaneous Generation
MACROEVOLUTION = big changes,
accumulated from small changes over long periods of time
MICROEVOLUTION = small
changes in the relative frequencies of traits (color) in a population
1)
Natural
Selection = differential, or unequal, success in reproduction. (compare to artificial)
2)
Adaptation
= share a common ancestor, that is species arise as the result of descent
with modification.
·
Assumptions
it is based upon:
1. variation within a
population
2. heritable traits
3. overproduction of offspring
4. selection pressures (limited
natural resources)
5. struggle to survive
6. preferential reproduction
7. small changes over geologic
time
What
is a species?
Biological Species
Definition!!!
A population or group of populations
whose members have the potential to interbreed and produce fertile offspring.
Evolutionary
Species Concept:
A species represents a cluster of
organisms that share a geneology, or lineage of descent.