Biol. 106 Lecture Topic # 15: Organization and Intro. to Diversity

Principles of Classification

I. Phylogeny

A. Objective

1. organize biological diversity

2. reflecting evolutionary history

3. descent with modification

B. Systematics

The study of relationships among organisms ~ reconstruction of phylogenies

2. Taxonomic hierarchy

a. 5 m - 30 m species of organisms

b. phylogeny- treelike diagram depicting evolutionary history

Kingdom - Animalia (worms & mammals), Phylum - Chordata (fish & mammals)

Class - Mammalia (mice and dogs), Order - Carnivora (bears and dog)

Family - Canidae (foxes & dogs), Genus - Canus (coyote & dogs)

Species - familiaris (dogs) DESCENT WITH MODIFICATION

Only derived similarities identify branches of the evolutionary tree.

II. 5 Kingdoms System

A. Monera (= Prokaryote): -only Prokaryotic Kingdom, -includes bacteria

B. Protista: -Diverse, -mostly unicellular Eukaryotes, -all other multicellular forms not included in 3 other kingdoms

C. Fungi: -primarily absorb all nutrients, -secrete extracellular enzymes, -nonmotile

D. Plantae: -autotrophs, 2nd absorb, -primarily stationary, w/ cell wall

E. Animalia: -heterotrophs- ingest food, -highly motile

III. Most Basic Distinction:

A. Prokaryotes

1. lack membrane bound organelles & microtubules

2. possess simple flagella

3. DNA circular double helix w/little protein

4. reproduce w/o nuclear divisions of meiosis and mitosis

5. "Masters of Metabolism" more diverse than eukaryotes

B. Eukaryotes

1. possess membrane bound organelles & microtubules

2. nucleus bound by double membrane

3. chromosomes complexed w/ protein

4. exhibit true sexuality

5. more complex flagella and cilia (9+2) structure of microtubules

6. more uniform metabolically