OrganizingLife'sDiversity

Section 1: Organizing Life’s Diversity Section

__ What You’ll Learn: __ The history, purpose, and methods of taxonomy The meaning of a scientific name The organization of taxa in a biological classification system

__ Review Vocabulary: __ species- Group of organisms that can interbreed and produce fertile offspring in nature.

__ New Vocabulary: __ Classification- Grouping of objects or information based on similarities taxonomyTaxonomy- Branch of biology that groups and names organisms based on studies of their shared characteristics; biologists who study taxonomy are called taxonomists. binomial nomenclature - Two-word system developed by Carolus Linnaeus to name species; first word identifies the genus of the organism, the second word is often a descriptive word that describes a characteristic of the organism. Genus- First word of a two-part scientific name used to identify a group of similar species. Specific Name- The second word of a species name. Order- Taxonomic grouping of similar families. Class- Taxonomic grouping of similar orders. Phylum- Taxonomic grouping of similar classes. Division- Taxonomic grouping of similar classes; term used instead of phyla by plant taxonomists. Kingdom- Taxonomic grouping of similar phyla or divisions. Classification

Biologists organize organisms in order to better understand them. They use **classification**, which is the grouping of objects or information based on similarities. The branch of biology that groups and names organisms based on the studies of their different characteristics is called **Taxonomy**. (Click to download model of levels)

Aristotle, the Greek philosopher, was the first to develop a widely accepted system of biological classification. Carolus Linnaeus, a Swedish botanist, developed a method of grouping organisms that is still used today. This system is based on physical characteristics and structures of the organism. Modern Classification systems use a two-word naming system called binomial nomenclature. The first word is the **genus** and it consists of a group of similar species. The second word is the **specific epithet**, which sometimes describes a characteristic of the organism. So, the scientific name for a species is a combination of the genus name and specific epithet. Latin is the language used in scientifically naming organisms and taxonomists are required to use Latin because it doesn’t change. Taxonomists now also try to identify evolutionary relationships based on the classification of organisms.

Classifying organisms provides a framework in which to study the relationships among living and extinct species. Classification can also be useful for scientists working in agriculture, forestry, and medicine. Taxonomy is helpful to the economy because it sometimes leads to the discovery of new sources of lumber, medicine, and energy. Living things are classified by taxonomic rankings. Organisms are ranked in taxa that range from having very broad characteristics to very specific ones. Following species and genus, is **family**, the next larger taxon in the biological classification system, and it consists of a group with similar genera. The next is an **order**, a taxon of similar families. A **class** is a taxon of similar orders. A **phylum** is a taxon of similar classes. Plant taxonomists use the taxon division instead of phylum. A **kingdom** is the taxon of similar phyla or divisions.

Lab

Classifying: Using a dichotomous key to identify a tree. How could you identify a tree growing near your home? You can identify trees by using a dichotomous key and leaves from the trees. A key is made of sets of numbered statements. Each statement deals with a single characteristic of an organism, such as leaf shape. The more you use the key, the more specific the characteristics become. Follow the numbered sets until the name of the organism is revealed.

Procedure: 1. Collect a few leaves from local trees. 2. Using a dichotomous key for each leaf, identify the tree from which each leaf came from.

Section 2: The Six Kingdoms

__ What You’ll Learn: __ How evolutionary relationships are determined How cladistics reveal phylogenetic relationships The six kingdoms of organisms

__ Review Vocabulary: __ Archaebacteria- chemosynthetic prokaryotes that live in harsh environments

__ New Vocabulary: __ Phylogeny- the evolutionary history of a species Cladistics - one biological system of classification that is based on phylogeny Cladogram- a branching diagram that biologists use and make by identifying a group’s derived traits Eubacteria- a kingdom in which organisms have very strong cell walls and a less complex genetic makeup than found in archaebacteria or eukaryotes Protist- a eukaryote that lacks complex organ systems and lives in moist environments Fungus- either a unicellular or multicellular eukaryotes that absorbs nutrients from organic materials in the environment

Evolutionary relationships are based on structural similarities, breeding behavior, geographical distribution, chromosomes, and biochemistry. There are six kingdoms of organisms. The first are prokaryotes**es**, which are microscopic, unicellular organisms that lack distinct nuclei bounded by a membrane. They are classified in the Kingdom **Eubacteria.**
 * Phylogeny ** is the evolutionary history of a species. **Cladistics** is a biological system of classification that is based on phylogeny. Biologists identify a group’s derived traits and use them to make a branching diagram called a **Cladogram**.

Second is a **protist**, which is a eukaryote that lacks complex organ systems and lives in moist environments.

Next, is **fungus**, which is either a unicellular or a multicellular eukaryote that absorbs nutrients from organic materials in the environment.

Next are plants. There are many kinds of plants, including flowering plants, mosses, ferns, and evergreens.

Last are **animals**. Animals are multicellular heterotrophs and nearly all are able to move from place to place.

Clips: [|Classification of Life] [|Kingdom Classification] [|Classification/Evolution] [|Classification Examples]

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