Chapter 1
Life: Biological Principles
& Science of Zoology
I. Science of Zoology
Scientific study of animal life; research guided by
2 Theories:
1. Theory of Evolution
2. Chromosomal Theory of Inheritance
II. General Properties of Life:
1. Chemical Uniqueness
- unique & complex molecular
organization
2. Complexity & Hierarchal Organization
(Table 1.1)
- unique & complex hierarchy (atoms → molecules →
macromolecules → cells → organisms → popuations)
3. Reproduction
- generate others like themselves (sexual or asexual)
4. Possession of Genetic Program
- nucleic acids (DNA) that provide development & fidelity of inheritance
5. Metabolism
- maintain themselves by acquiring nutrients from their
environments
6. Growth & Development
- passing through a life cycle
(characteristic changes from
origin to its final adult form)
7. Environmental Interaction
- interact or respond with environment (ecology)
8. Movement
- precise & controlled movements arising from within the
system
Follow the laws of physics & chemistry
III. Zoology – part of Biology
1. Animals form a distinct branch on the evolutionary
tree of life
2. Large & old branch
(over 600 mya) of eukaryotes
IV. Principles of Science
Nature of Science:
Judge Overton’s 5 characteristics of Science:
1. Science guided by Natural Law
2. Has to be explanatory by reference to
Natural Law
3. Testable against the observable world
4. Conclusions are tentative; not the final word
(flexible)
5. It is falsifiable.
Hypothetico-deductive method:
Make conjectures then test for rejection
Follow the scientific method
Scientific Method Steps:
O – Observations & Questions
H – Hypothesis or potential answers with
general statements
null hypothesis – made to reject
E – Experiment (empirical test)
C – Conclusion
(Publication)
2 Categories tested:
Experimental Science (proximate causes)
Evolutionary Science (ultimate causes)
V. Theories of Evolution & Heredity
Charles Darwin’s five theories:
1. Perpetual Change
2. Common descent
3. Multiplication of
species
(new species by splitting
or transforming others)
4. Gradualism
- large differences accumulation of many small
incremental changes
5. Natural Selection
3 propositions:
a. genetic variation in populations
b. heritable traits
c. differential reproduction
Mendelian Heredity & the Chromosomal Theory
1. Phylogeny –
Evolutionary history of a taxon’s origin & diversification
Based on a variety of information
2. Chromosomal Inheritance –
- Foundation
for current studies of genetics & evolution
in animals
- Theory from consolidation of research done in fields of
genetics & founded by Gregor Mendel’s work:
Mendel’s Particulate Theory
- hereditary factors are discrete entities that
do not blend when transmitted (genes)