Taxonomy (8 levels)

Taxonomy

Overview of Taxonomy

  • Taxonomy is the science of classification of living organisms into structured categories known as taxons.

Discussion #2: 8 Levels of Taxons

  • Taxonomic hierarchy consists of 8 distinct levels, which are essential for categorizing life forms.

Key Figures in Taxonomy

Carl Linnaeus

  • Known as the "Father of Modern Taxonomy" (1707-1778).

    • Established a systematic approach to classify organisms based on structural similarities and differences.

    • Created the binomial nomenclature system, involving two names to identify organisms.

    • Classifications divided mainly into plants and animals.

    • Noteworthy for his detailed sketches and illustrations of various species.

Types of Cells

Cell Classification

  • Two primary cell types exist:

    • Prokaryotic Cells:

    • Characteristics:

      • Smaller size.

      • Lack organelles.

      • Nucleus is not membrane-bound (loose nucleus).

      • Typically unicellular organisms.

    • Eukaryotic Cells:

    • Characteristics:

      • Larger size.

      • Contain membrane-bound organelles (e.g., mitochondria, endoplasmic reticulum, chloroplasts).

      • Possess a true nucleus.

      • Can be multicellular organisms.

  • Comparison consists of understanding the fundamental differences between prokaryotic and eukaryotic cells, e.g., bacteria vs. animal cells.

Taxonomic Hierarchy

8 Levels of Taxons

  1. Domain (3 total):

    • Highest taxonomic rank; introduced in 1990 by microbiologist Carl Woese.

    • 3 domains encompass all life forms:

    1. Archaea (Examples: Halophiles, Hyperthermophiles)

    2. Bacteria (Examples: Cyanobacteria, Mycoplasmas)

    3. Eukarya (Includes all complex life forms)

    • Facts:

      • Each domain contains unique ribosomal RNA (rRNA) for protein synthesis.

  2. Kingdom (5 total):

    • Each domain is further divided into kingdoms.

      • Domain Archaea = Kingdom Archaea

      • Domain Bacteria = Kingdom Bacteria

      • Domain Eukarya = 3 kingdoms:

      • Kingdom Protista (Examples: Amoeba, slime molds)

      • Kingdom Fungi (Examples: Mushrooms, yeast)

      • Kingdom Plantae (Examples: Roses, Cherry trees)

      • Kingdom Animalia (Examples: Kinkajou, Flying Gurnard, Leaf Slug)

  3. Phylum (108 known phyla):

  4. Class (Not Applicable):

  5. Order (Not Applicable):

  6. Family (7,500 known families):

  7. Genus (174,000 known genera):

  8. Species (1.2 million identified species and an approximate total of 8.7 million):

    • Taxon: Defined as any taxonomic group of any rank or level.

Examples of Taxonomic Classification

Example 1: Grizzly Bear

  • Kingdom: Animalia

  • Phylum: Chordata

  • Class: Mammalia

  • Order: Carnivora

  • Family: Ursidae

  • Genus: Ursus

  • Species: horribilis

Example 2: Canada Goose

  • Domain: Eukarya

  • Kingdom: Animalia

  • Phylum: Chordata

  • Class: Aves (birds)

  • Order: Anseriformes

  • Family: Anatidae (ducks, geese, swans)

  • Genus: Branta (true geese)

  • Species: canadensis (Canada)

Scientific Naming Conventions

Binomial Nomenclature

  • Scientific names consist of two parts: a genus name and a specific epithet (species).

    • Represents the most specific level in taxonomy.

    • Developed by Carl Linnaeus.

    • Formatting: Scientific names are italicized with the genus name capitalized and the species name in lowercase.

Examples of Scientific Names:

  • Red Maple: Acer rubrum

    • Acer (maple)

    • rubrum (red)

  • Jaguar: Panthera onca

    • Panthera (all beast)

    • onca (lynx)

  • Bat star: Patiria miniata

    • Patiria (suffer)

    • miniata (red)

Challenges with Common Names

  • Common names can lead to confusion as they are not universal and often non-descriptive.

    • Examples include:

    • Jellyfish

    • Starfish

    • Prairie dog

    • Horseshoe crab

    • Cowbird

  • A species can have multiple common names, e.g., the osprey known as Pandion haliaetus has various common names including fish hawk, river hawk, and sea hawk.

Importance of Taxonomy

  • The necessity of using 8 taxons stems from the complexity of categorizing the vast diversity of life on Earth.

  • The binomial system allows for a standardized method of naming organisms, ensuring specificity and clarity across different languages and regions.