Organizing Lifes Diversity

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Organizing Lifes Diversity
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History of Classification

• Aristotle (384-322 B.C.)
• Greek philosopher
• Aristotles System
• Animals
• Habitat
• Physical characteristics
• Plants
• Herbs, shrubs, or trees
• Depends on their size and structure

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Shortcomings of system

• Some animals lived on land and in water
• Did not show evolutionary history
• Birds, bats, and flying insects were grouped
  together because they all can fly

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Linnaean System

• Carolus Linnaeus (1707 1778)
• Swedish botanist
• Linnaean system
• Based on physical and structural similarities
• Plants
• Numbers and similarities of their reproductive
  structures

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Binomial nomenclature

• Developed by Linnaus
• Two names
• Genus
• Group of similar species
• Species (specific epithet)
• Descriptive name
• Ex. Genus species or Genus species
• Homo sapiens or Homo sapiens
• Also called the scientific name

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Modern Classification

• Identifies the evolutionary relationships of
  organisms
• Compare internal and external structures
• Compare geographical distribution and genetic
  makeup
• Makes it easier to understand biological diversity

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What does taxonomy do?

• Provides a framework to study relationships among
  living and extinct species
• A tool to identify organisms for medicine,
  forestry, and medicine
• Discovery of new sources of lumber, medicine, and
  energy

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• Taxon (pl. taxa)
• Group of organisms
• Organisms are ranked in taxa from very broad
  characteristics to very specific ones

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Taxonomic rankings
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
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Domain

• Contains one or more kingdoms

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Kingdom

• Taxon of similar phyla or divisions

Animalia
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Phylum/Division

• A taxon of similar classes
• Phylum Animals
• Division Plants

Chordata
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Class

• A taxon of related orders

Mammalia
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Order

• A taxon of related families

Carnivora
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Family

• A group of related genera (sing. genus)

Felidae
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Genus

• Group of similar species

Panthera
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Species

• Specific epithet
• Describes a characteristic of the organism

tigris
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Evolutionary relationships are determined by

• Structural similarities
• Breeding behavior
• Geographical distribution
• Chromosome comparisons
• Biochemistry

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Phylogenetic classificaion

• Phylogeny
• Evolutionary history of a species
• Cladistics
• Based on phylogeny
• Cladogram
• Model of the phylogeny of a species
• Similar to pedigrees or family trees

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Cladogram
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Fan-like models

• Gives the time organisms became extinct or
• Relative number of species in a group
• See page 454-455 of your text

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The Six Kingdoms
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Eubacteria

• Microscopic, unicellular
• Have strong cell walls
• Live in most habitats except extreme ones

Cyanobacteria
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Archaebacteria

• Microscopic, unicellular
• Live in extreme environments, like hydrothermal
  vents

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Protists

• Eukaryote very diverse
• Lack complex organ systems
• Live in moist environments
• Include all microorganisms that are not bacteria
• Ex. Algae and slime molds

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Fungi

• Unicellular or multicellular
• Absorb nutrients from organic materials in the
  environment

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Plants

• Multicellular, photosynthetic eukaryotes
• Contain chloroplasts

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Animals

• Multicellular consumers
• Heterotrophs
• Have cell membranes

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Dichotomous Key

• A device used for easily and quickly identifying
  an unknown organism.
• Couplets
• two statements based on characteristics of the
  organism
• By always taking the correct choice, the name of
  the organism will be revealed.

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Vertebrate Key