Classification of Living Organisms

Taxonomy

The science of describing, naming, and classifying organisms

Classification

Arranging organisms into groups based on their similarities

Systematics

The scientific study of the diversity of organisms and their natural (evolutionary) relationships

Taxonomy hierarchical grouping of classification

• Domain

• Kingdom

• Phylum (or Division)

• Class

• Order

• Family

• Genus

• Species - is the basic unit of classification (but not the smallest taxonomic group)

  • subspecies

  • varieties

  • cultivar

Reasons to classify

1. To ensure that the right plants are named correctly for ease of identification and grouping

2. It helps identify new species

3. Helps to remember the diversity of plants when they’re better organized

4. Help us identify relationships between different plants and other organisms

Six kingdoms of life

1. Bacteria

2. Archaea

3. Protista

4. Fungi (Myceteae)

5. Animalia

6. Plantae

(BAPFAP)

Bacteria

• Domain: Bacteria

• E.g.: Nitrogen-fixing bacteria, cynobacteria, lactic acid bacteria, enterobacteria (in intestines of humans and other animals)

• Characteristics: prokaryotic (lack distinct nuclei and other membranous organelles), singled celled, microscopic, cell walls composed of peptidoglycon

Archaea

• Domain: Archaea

• E.g. Halophiles (live in salt ponds), thermoacidophiles (live in hot sulfur springs), methanogens (live in swamps, digestive tracts of humans and other animals)

• Characteristics: prokaryotic (lack distinct nuclei and other membranous organelles), singled celled, microscopic, cell walls without peptidoglycon, different from bacteria chemically, adapted to extreme environments such as hot springs and undersea thermal vents

Protista

• Domain: Eukarya

• E.g. Euglenoids, Dinoflagellates,Diatoms, Golden brown algae Yellow-green algae Green algae, Brown algae, Red algaelgae, slime molds, water molds, prolozoa

• Characteristics: Eukaryotic (posses distinct nuclei and other membranous organelles), single celled or simple multicellular, varied modes of nutrition (some photosynthetic, some consume food, some absorb nutrients)

Fungi

• Domain: Eukarya

• E.g.: Mushroom, puffball, mildews, yeast, disease causing fungi, mycorrhizae

• Charcteristics: Eukaryotic, multicellular, photosynthetic, multicellular reproductive organs, cell walls of cellulose

3 Main Types:

• Biotrophs: obtain nutrients from other organisms without killing them

• Necrotrophs: Attack attack living hosts virulently, killing the hosts and then absorb released nutrients

• Saprotrophs: obtain nutrients from dead organisms

• • Some important fungi:

  1. yeast

  2. disease causing fungi, e.g. rot, rust, damping-off, powdery mildew, downy mildew, in plants.

  3, edible fungi, e.g mushrooms (class: basidiomycetes)

  4. mycorrhizae

Plantae

• Domain: Eukarya

• E.g. Mosses, ferns, pines, flowering plants

• Characteristics: Eukaryotic, multicellular, no cell walls, nonphotosynthetic, consume other organisms, move about by muscular contraction, specialized nervous tissue to coordinate responses

Vascular plants:

(A) seedless plants

• phylum Lycopodiophyta (club mosses)

• Phylum Pteridophyta (ferns, whisk ferns, horsetails)

(B) seed plants

1. plants with naked seeds (gymnosperms)-

• phylum coniferophyta (conifers)

• phylum cycadophyta (cycads)

• phylum ginkgophyta (ginkgoes)

• phylum gnetophyta (gnetophytes)

1. plants with seeds enclosed within a fruit

   • Phylum Anthophyta (angiosperms or flowering plants)

   • Class is eudiocotyledones (eudicots) OR DICOTS

   • Class Monocotyledones (monocots)

Plantae: Non-vascular plants

• Phylum Brophyta (mosses) - dominant generation

• Phylum Hepatophyta (liverworts)

• Phylim Anthocerophyta (hornworts)

Gymnosperms

• cone-bearing,

• vascular non-flowering (naked seeded)

• E.g. pines, have male cones and female cones, no flowers

Angiosperms

• flowering plants, dicots and monocots

Monocotyledon

• Commonly referred to as Monocots

• One of the two main classes of flowering plants

• Monocot seeds contain a single cotyledon (one seed leaf)

• Usually have parallel leaf venation

• The parts of monocot flowers usually occur in multiples of threes, e.g. three sepals, three petals, six stamens, e.g. their sepals, petals, stamens, etc. usually occur in multiples of three

• Includes grasses, orchids, onions, lilies and palms

Dicotyledon

• Commonly knows as Dicots (Eudicots)

• One of two main classes of flowering plants.

• Dicot seeds contain two cotyledons (have two seed leaves)

• net leaf venation

• Flower parts e.g. and their sepals, etc. usually occur in multiples of 4 or 5