1. Identifying, Naming, and Classifying Species

2. Taxonomy
the branch of biology that identifies, names, and classifies species (alive and extinct)
Callicebus caquetensis, a species of titi monkey, was discovered in the Colombian Amazon. (AP, 2010)

3. How do we identify and name a species?
Species: a group of organisms that can interbreed in nature and produce fertile offspring
This is the most recognized def’n of a species
Does this definition fit all organisms?
Callicebus caquetensis, a species of titi monkey, was discovered in the Colombian Amazon. (AP, 2010)

4. Species Concepts
No one def’n fits everything, so we identify species based on three different species concepts (or definitions for a species)
Biological species concept
Morphological species concept focuses on morphology – compares body shape, size, and other structural features
Morphology = branch of biology that deals with structure or form of organisms
Juvenile/Adult Koran Semicircule Angle fish (Pomacanthus semicirculatus)
Males can differ from females
juvenile change appearance as they grow or age
pop’n of same species can vary in different locations and exhibit striking differences

5. Species Concepts
3. Phylogenetic species concept examines the phylogeny, or evolutionary history, of organisms
Phylogeny = the evolutionary history of a species
- need to obtain genetic material from specimens and use DNA sequencing techniques
- this is a powerful tool, but not always practical or possible to obtain a sample
Juvenile/Adult Koran Semicircule Angle fish (Pomacanthus semicirculatus)
Males can differ from females
juvenile change appearance as they grow or age
pop’n of same species can vary in different locations and exhibit striking differences

6. The ‘father’ of taxonomy
Carl Linnaeus (1707 – 1778) – a Swedish naturalist and botanist
Developed the first consistent classification system
Established a latin naming system which gave each species a unique two part name

7. Binomial Nomenclature (two part naming system)
The first name is the genus name
Genus = taxonomic level consisting of a group of closely related species
Genus is Capitalized and in italics
The second name is the species name (specific name)
Species name identifies the particular species
Species is lower case and in italics
E.g. Homo sapiens

8. Binomial Nomenclature
Ursus americanus
Ursus maritimus
Phascolarctos cinereus

9. Classification in Biology
Biological classification = the systematic grouping of organisms into categories on the basis of defined criteria e.g. Grouping of organisms into trophic levels

10. Linneaus’ Classification System
Based on a hierarchical classification that has seven main levels or taxa
Kingdom
Phylum
Class
Order
Family
Genus
Species
general
Taxa = category used to classify organisms
specific

11. Taxon (taxa plural) = a named group of organisms such as phylum Chordata or order Rodentia
Rank = a level in a classification scheme, such as phylum or order

12. A Closer Look at the Kingdoms
one of the disputes among taxonomists involve the number of Kingdoms
In this course we will use the six Kingdom system:
Bacteria
Archaebacteria
Protista
Fungi
Plants
Animals

13. Dichotomous Keys
a series of branching “either / or” choices designed to classify specimens

14. A sample Dichotomous Key