1. Biology

2. Chapter 13 Classification
I. Classification – grouping of objects or information based on similarities
A. Taxonomy – branch of biology that identifies and classifies organisms.
1. Linnaeus – also known as Carl von Linne
a. Swedish botanist that developed the system of modern taxonomy.
b. Based his classifications on structural similarities.
c. Had a two kingdom system.

3. B. Levels of Classification
1. Kingdom – most general category
2. Phylum
3. Class
4. Order
5. Family
6. Genus
7. Species – similar in appearance and structure and have the
same number of chromosomes.
- plant kingdom has divisions instead of phyla

4. C. Five Kingdoms – most commonly used system
1. Monera – unicellular, prokaryotic organisms.
a. Include all bacteria
b. Live almost anywhere
2. Protista – unicellular and multicellular eukaryotes
a. Plant-like, Animal-like, and fungus-like.
b. Algae, paramecium, amoeba
3. Fungi – heterotrophic, eukaryotic organsisms
a. Live on other organisms
b. Molds, mushrooms, and yeasts
4. Plants – multicellular eukaryotes
a. Most are autotrophs
b. Include mosses, ferns, cone-bearing, and flowering plants.

5. 5. Animal – multicellular, eukaryotic, and heterotrophic
a. Most are capable of movement
b. Includes sponges, insects, amphibians, reptiles, fish, birds, etc.

6. D. Naming Organisms
1. Binomial Nomenclature – naming system in which each individual
receives a two part name.
a. Names are in Latin
b. Genus is first name, species is the second
c. First word is capitalized, second is lower case
d. Name is italicized, or underlined
ex – Rana pipens or Rana pipiens
Canis lupus
Turdis migratorious
Panthera leo
2. Used to avoid confusion of common names.

7. II. Basis for Classification
A. By evolutionary history
1. Phylogenetic Tree – shows the evolutionary relationship among
organisms.
a. Based on fossil records and structural & molecular comparisons.
b. Branch points of a tree represent common ancestors.
c. The closer organisms are on the tree, the more closely they are
related.
B. By Biochemistry
1. Proteins and DNA are compared
a. The more similar the DNA sequences are, the closer they are related.

8. C. Structural Similarities
1. Observation of physical features is used to classify organisms.
2. Some structures can be misleading.
ex – fins, wings, teeth, etc.
D. Problems in Classification
1. Taxonomy is constantly changing as new information is discovered.
2. Not everyone uses the same methods to classify organisms and some
use different kingdom systems.

9. III. Identifying Organisms
A. Dichotomous Key – a guide designed to identify organisms.
1. List specific observable traits, and for each trait lists contrasting options.
2. Choice of contrasting options eventually lead to identification of the
organism.

10. Skeletal Muscle Fiber Each Skeletal Muscle Fiber
is a cylindrical muscle cell. An individual skeletal muscle fiber may be composed of hundreds, or even thousands of muscle fibers bundled together and wrapped in a connective tissue covering.

11. Myofibrils
Myofibrils are found in the sarcoplasm and are seperated into compartments called sacromeres that contain thick filaments and thin filaments.
The thick filaments of myofibrils are made up of the protein myosin where as the thin filaments are made up of the protein actin.
The organization of these filaments produce the image of striations.