Zoology - Biology 212
Winter Quarter
Lake Tahoe Community College
Instructor: Sue Kloss
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Animal Classification, Organization and Taxonomy
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Animal Classification, Phylogeny and Organization
I. Intro
A. Biologists have named and described approx. 1.75 million species
B. More than .75 of these are animals
C. Many zoologists group organisms by shared characteristics
II. Classification of Organisms
A. Intro
1. A classification system reflects the order and relationships that arise from evolutionary
processes
2. systematics; taxonomy is the naming and classifying of organisms
B. Taxonomic hierarchy
1. Karl von Linne - Carolus Linnaeus 2. grouped different species into broader categories based on shared characteristics
3. taxon - kpcofgs.
C. Nomenclature
1. binomial nomenclature
D. Molecular approaches to systematics
1. molecular bio has provided important info for taxonomy of plants and animals
2. relatedness of particular organisms
3. genes and proteins
4. mutation rate is constant
5. using mitochondria
6. this is called a molecular clock
E. Domains of Life
1. Whittaker - 1969 - described 5 kingdoms based on cellular organization and mode of
nutrition This has been changed to domains – Archaea, Bacteria, Eukarya
2. Ribosomal RNA
3. biologists compare ribosomal RNA of different organisms
4. look at all possible arrangement and figure out which arrangement best explains data
5. Studies of ribosomal RNA indicates that there are 3 main evolutionary lineages - domains
6. domains (Bacteria, Archaea, Eukarya) are broadest taxonomic grouping
F. Animal systematics 1. goal is to arrange animals into groups that reflect evolutionary relationships
2. ancestral species and all descendants - monophyletic group
a. characters -measurable
3. monophyletic group
4. paraphyletic group
5. polyphyletic group
6. 3 different schools have developed
a. evolutionary systematics
b. numerical taxonomy c. phylogenetic systematics - also called cladistics
III. Evolutionary Relationships and tree diagrams
A. tree diagrams misleading bc they depict broader taxa as units of evolution
B. trees also imply that complexity is increasing
IV. Patterns of Organization
A. Intro
B. Symmetry - how an animal body plan is organized around a point or axis
1. asymmetry
2. radial symmetry
3. bilateral symmetry
a. cephalization
C. Other patterns of organization (not exact sequences in animal evolution
1. unicellular organization
2. Diploblastic - tissue level organization - body parts are organized in 2 layers from 2 embryonic tissue
layers - endoderm (gut) and ectoderm (outer layer of organism)
3. Triploblastic organization
a. endo, ecto and mesoderm - mesoderm
4. triploblastic animals divided into several groups
a. organs can be suspended and separated from body wall
b. advantages c. types
1. acoelomate 2. pseudocoelomate 3. coelom
IV. Higher Animal Taxonomy
A. Intro
1. At beginning of Cambrian period, 600mya, explosion in evolution resulting in all modern animal phyla
and many that have gone extinct
2. Disagreement
3. Most taxonomists use branches to help understand major groups in animal kingdom
4. comparative embryology to sort groups out
a. protostomes
b. deuterostomes
5. lots of controversy, our book will use traditional approach till consensus is reached
Homework Questions/Lesson Objectives
1. Define all underlined terms in lecture notes.
2. Know the taxonomic system developed by Linnaeus (DKPCOFGS)
3. Correctly write the binomial nomenclature for your species.
4. What does our current classification system for animals reflect and represent?
5. Why do we use scientific names?
6. What are 2 benefits to using molecular approaches in systematics?
7. What are the 5 kingdoms? Why is ribosomal RNA often used to distinguish between groups at this level?
8. Describe the 2 major types of characters used currently by systematists.
9. Describe the 3 main schools of animal systematics.
10. Why do different schools disagree?
11. What information is given in a phylogenetic tree vs. a cladogram? What are the disadvantages of each?
12. Describe various types of animal symmetry.
13. Describe various types of animal cell and tissue level organization
14. What are the advantages of having a body cavity?
15. Describe various types of animal body cavities
16. describe the main traits of protostomes vs. deuterostomes.
17. describe the main traits that distinguish the Lophotrochozoans .
18. describe the main traits that distinguish the Ecdysozoans.