1. 18-1 Finding Order in Diversity
Photo credit: ©Gary Randall/Visuals Unlimited
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2. 18-1 Finding Order in Diversity
Natural selection and other processes have led to a staggering diversity of organisms.
Biologists have identified and named about _______ million species so far.
They estimate that anywhere between_______million additional species have yet to be discovered.
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Why Classify?
Why Classify?
To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner.
In the discipline of______________, scientists classify organisms and assign each organism a universally accepted name.
When taxonomists classify organisms, they organize them into groups that have___________significance.
To avoid the confusion caused by regional names, biologists use a classification system to group organisms in a logical manner and to assign names.
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4. Assigning Scientific Names
Common names of organisms vary, so scientists assign one name for each species.
Because 18th century scientists understood_____and __________, they used those languages for scientific names.
This practice is still followed in naming new species.
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5. Assigning Scientific Names
Early Efforts at Naming Organisms
The first attempts at standard scientific names described the_______characteristics of a species in great detail.
These names were not standardized because different scientists described different characteristics.
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6. Assigning Scientific Names
Binomial Nomenclature
Carolus_______, a Swedish botanist who lived in the 18th century, developed a naming system called ____________________________________.
In binomial nomenclature, each species is assigned a two-part scientific name.
The scientific name is __________, the first word is capitalized, and the second word is lowercased.
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7. Assigning Scientific Names
The first part of the name is the genus to which the organism belongs.
A_________is a group of closely related species. The genus name is____________.
The second part of the name is unique to each ____________within the genus.
This part of the name often describes an important trait or where the organism lives. The species name is _________________.
For example, a grizzly bear is known as ________________________.
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8. Linnaeus's System of Classification
Linnaeus not only named species, he also grouped them into categories.
Linnaeus's_________levels of classification are—from smallest to largest—
species
genus
family
order
class
phylum
kingdom
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9. Linnaeus's System of Classification
 Each level is called a______, or taxonomic category.
Species and genus are the two smallest categories.
Grizzly bear
Black bear
Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level.
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10. Linnaeus's System of Classification
Genera that share many characteristics are grouped in a larger category, the___________.
Grizzly bear
Black bear
Giant panda
Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level.
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11. Linnaeus's System of Classification
An ________is a broad category composed of similar families.
Grizzly bear
Black bear
Giant panda
Red fox
Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level.
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12. Linnaeus's System of Classification
The next larger category, the______, is composed of similar orders.
Grizzly bear
Black bear
Giant panda
Red fox
Abert squirrel
Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level.
Class Mammalia
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13. Linnaeus's System of Classification
Several different classes make up a ____________.
Grizzly bear
Black bear
Giant panda
Red fox
Abert squirrel
Coral snake
PHYLUM Chordata
Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level.
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14. Linnaeus's System of Classification
The ___________ is the largest and most inclusive of Linnaeus's taxonomic categories.
Grizzly bear
Black bear
Giant panda
Red fox
Abert squirrel
Coral snake
Sea star
KINGDOM Animalia
Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level.
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15. Linnaeus's System of Classification
Grizzly bear
Black bear
Giant panda
Red fox
Abert squirrel
Coral snake
Sea star
Linnaeus’s hierarchical system of classification uses seven taxonomic categories. This illustration shows how a grizzly bear, Ursus arctos, is grouped within each taxonomic category. Only some representative species are illustrated for each category above the species level.
Copyright Pearson Prentice Hall