Biology 1A Sept 24, 1998
Lecture 8 - Systematics
Page Contents :
Overview of Lecture:
Nomenclature is the science of naming organisms.
Taxonomy is the science of the classification of organisms.
Systematics is the science of the relationships of organisms.
Phylogenetics is the science of the pattern of evolution.
I. Nomenclature is the science of naming organisms.
A. Evolution has created an enormous diversity, so how do we deal with it?
II. Taxonomy is the science of the classification of organisms.
B. Names allow us to talk about groups of organisms.
1. Scientific names were originally descriptive phrases; not practical
2. Binomial nomenclature
a. Developed by Linnaeus, a Swedish naturalist
3. Thus a species' name is two words.
b. Names are in Latin, formerly the language of science
c. binomials - names consisting of two parts
d. The generic name is a noun.
e. The epithet is a descriptive adjective.
A. Taxonomy deals with the naming and ordering of taxa.
III. Systematics is the science of the relationships of organisms.
B. The Linnaean hierarchy:
C. The nature of a hierarchy
D. The difference between classification and identification.
A. Systematics is the science of how organisms are related and the evidence for those relationships.
IV. Phylogenetics is the science of the pattern of evolution.
B. Systematics is divided primarily into phylogenetics and taxonomy.
C. Speciation -- the origin of new species from previously existing ones.
1. anagenesis - one species changes into another over time
2. cladogenesis - one species splits to make two
A. Evolutionary biology is the study of the processes that generate diversity, while phylogenetics is the study of the pattern of diversity produced by those processes.
B. The central problem of phylogenetics:
1. How do we determine the relationships between species?
C. Cladistics is phylogenetics based on synapomorphies.
2. Use evidence from shared characteristics, not differences
3. Use homologies, not analogies.
4. Use derived condition, not ancestral
a. synapomorphy - shared derived characteristic
b. plesiomorphy - ancestral characteristic
1. Cladistic classification creates and names taxa based only on synapomorphies.
2. This is the principle of monophyly.
3. monophyletic, paraphyletic, polyphyletic
4. Cladistics is now the preferred approach to phylogeny.
|anagenesis|| || ||
||family|| || ||
|analogy|| || ||
||genus (genera)|| || ||
|binomial|| || ||
||hierarchy|| || ||
|cladistics|| || ||
||homology|| || ||
|cladogenesis|| || ||
||identification|| || ||
|class|| || ||
||kingdom|| || ||
|classification|| || ||
||monophyletic|| || ||
|convergent evolution|| || ||
||nomenclature|| || ||
|division|| || ||
||order|| || ||
|epithet|| || ||
||paraphyletic|| || ||
- Why is nomenclature important?
- Why was the development of binomial nomenclature so important?
- What is taxonomy, and how does it differ from nomenclature?
- What is a hierarchy? What are some examples of hierarchy?
- If an order of plants has twelve families and 400 species, what is the minimum number of genera possible in the order? What is the maximum number possible?
- To which level of the hierarchy would the group Liliales belong? Liliopsida? Liliaceae? Lilium michiganensis?
- Explain the difference between classification and identification. Which are you doing if you use a field guide to locate the name for a plant in your yard?
- How are cladogenesis and anagenesis different? How are they similar? Can cladogenesis occur by gradualism? by punctuation?
- What is the central problem of phylogenetics? What principles are used to solve this problem?
- Are the wings of insects and birds an example of convergence or homology?
- Which of the following characteristics are synapomophies for fungi? Which are plesiomorphies?
chitin in cell wall
- Diagram and explain the difference between monophyly, paraphyly, and polyphyly.
- Are the algae monophyletic, paraphyletic, or polyphyletic? What about fungi? What about eukaryotes?
© 1998 Brian R. Speer. These pages for the personal use of students and teachers; any commercial use or publication is strictly prohibited.