Associated Lab(s)  Quiz

Unit II - Populations

Refer to Chapter 37
Biology: The Study of Life. 5th ed. Schraer and Stoltze © 1993

Define taxonomy.

Taxonomy is the branch of biology that deals with the identification and naming of living things.

Explain the function of classification system.

The main function of a classification system is to allow biologists to group organisms according to similar characteristics. This organization helps biologists study living organisms and to make predictions about their relationships, including structural information, biochemical information, cytological information, embryological information, behavioural information and fossil information.

Explain how classification today is based on increasingly narrower categories, using the species as the basic identifying level.

The modern classification system is based on increasingly narrower (more specific) categories. The broadest category is the kingdom and the most specific category is the species. The categories from most general to most specific are kingdom. phylum, class, order, family, genus, and species.

Define nomenclature.

Nomenclature is a term that refers to a system for naming organisms. In biology the system is "binomial" meaning that two names are used to specifically identify every organism - genus and species.

Describe the binomial system of nomenclature used in modern biology.

The binomial system uses a two word latin name to identify a specific type of organism. This is similar to the use of a first name and a last name to identify a person. The genus name and species name are the two words used. For example the binomial name for the fragrant water lily is Nymphaea ordorata. Notice that the genus name is always capitalized and the species name is never capitalized.

Name the five kingdoms used in modern biology and describe the main characteristics of each.

The five kingdoms used in modern biology are kingdom Monera, kigndom Protista, kingdom Fungi, kingdom Plantae, and kingdom Animalia.

Monera:
Monera include all the prokaryotic organisms or bacteria. This group of living organisms do not have any internal membranous organelles such as a nucleus, golgi apparatus, endoplasmic reticulum, ect. They do have a nucleoid region containing a chromosome organized into a circle, and they also have ribosomes for protein synthesis. Some forms are responsible for causing disease in humans. Most are important decomposers, and are also important in the recycling of nutrients.

Protista:
Members of the Protista are generally unicellular, eukaryotic organisms, although some multicellular forms are also included. Some forms are responsible for causing disease in humans.

Fungi:
Fungi include molds, yeasts, mushrooms, rusts, and smuts. This group of organisms are eukaryotic, heterotrophic organisms that mainly serve as decomposers important to the recycling of materials. Some forms are responsible for causing disease in humans.

Plantae:
Plantae include mosses, liverworts, ferns, confers and flowering plants. Plants are multicellular. eukaryotic, photosynthetic organisms that form the basis of the food web in terrestrial ecosystems.

Animalia:
Animalia include the animals of this world and represent the largest of the five kingdosm (more species than any other kingdom). Animals are multicellular, eukaryotic, heterotrophs. Animals generally have the greatest degree of system development since they generally have senses for detecting food and mobility to capture it. Animals form all of the consumer levels of the food web in any ecosystem. Their wastes and dead bodies however are consumed by fungi and bacteria.

Explain the advantages of the five kingdom system of classification.

The advantage of a five kingdom classification system is that there is far less overlap and confussion as compared to the original two kingdom classification system as proposed originally by Linneaus. There are still some problems with the five kingdom system and taxonomists are still working on improvements. One suggested improvement is to adopt a Domain system or a six kingdom system of classification.

Show how taxonomic keys, often dichotomous in nature, can be used to help classify certain organisms.

The dichotomous system consists of a series of two point (paired) choices that deal generally with the presence or absence of characteristics that are easily identifyable in the organism. Each pair of statements in the dichotomous key gets more specific until the species is finally identified.

 Visit the section on Classification at the Online Biology Book