SM

5.7 Classification & Dichotomous

Scientific Classification

Domains

The 3 domains are: Archaea, Eubacteria, and Eukaryote

older systems do not include domain

Binomial Nomenclature

Binomial Nomenclature, meaning how organisms are named, is determined by the Genus and Species. When writung names using Binomial Nomenclature, the names must be underlined or italicized. Genus must be capitalized species.

Mnemonic for Remembering the Order of Scientific Classification

Dumb

King

Phillip

Came

Over

For

Good

Soup

Dichotomous Key

This is a method used by taxonomists to identify unknown organisms based on their characteristics. It is made up of a series of numbered couplets, defining one of two group that the organism could fall into. Couplets begin with general characteristics and become successively more specific, as you get closer to identifying the species.

An example couplet:

a) Has a backbone: go to 2

b) Lacks a backbone: go to 10

Plant Phyla

  • There are 10 plant phyla

Bryophyta (mosses)

  • Includes mosses, hornworts and liverworts

  • No true leaves or roots

  • No cuticle

  • Reproductive structures are called sporangium which are on long stalks with capsules on end

  • Reproduce using spores

Filicinophyta (ferns)

  • A non-woody, vascular plant

  • Have roots and stems

  • Have divided leaves with veins

  • Reproduce using spores

  • Most produce spores on underside of leaves

Coniferophyta (conifers)

  • A woody, vascular plant or shrub

  • Needle-like, waxy leaves

  • Use cones to reproduce

  • Male cones produce pollen

  • Female cones contain embryo

Angiospermophyta (flowering plants)

  • Vascular trees, shrubs and bushes

  • Flower bearing plants

  • Flower produces pollen and ova

Animal Phyla

Porifera (sponges)

Mouth/Anus

Symmetry

Skeleton

no

no

internal spicules

  • filter feeds

  • diverse body shapes

Cnidaria (jellyfish, corals, sea anemones)

Mouth/Anus

Symmetry

Skeleton

1

radial (symmetry for the center of organism)

soft (except corals)

  • tentacles arranged in rings around mouth

  • have cnidocytes that fire little harpoons

Platyhelminthes (flatworms)

Mouth/Anus

Symmetry

Skeleton

yes

bilateral

none

  • have no body cavity

  • have no circulatory or respiratory system

  • flat body

Annelida (ringed worms)

Mouth/Anus

Symmetry

Skeleton

yes

bilateral

fluid under pressure

  • segmented body parts

  • most have closed circulatory system

Mollusca (snails and clams)

Mouth/Anus

Symmetry

Skeleton

yes

bilateral

most have hard shells

  • the mantle is folded to form a cavity

  • open circulatory system

  • shell is secreted by mantle

Arthropoda (insects, spiders, crustaceans)

Mouth/Anus

Symmetry

Skeleton

yes

bilateral

exoskeleton made of chitlin

  • they have a head, thorax and abdomen

  • segmented body

Chordata (fish, amphibians, reptiles, birds, mammals)

Mouth/Anus

Symmetry

Skeleton

yes

bilateral

endoskeleton (vertebrae)

  • a notochord

  • a dorsal hollow nerve cord

  • a post-anal tail

  • pharyngeal slits

Chordata Classes