L1: Classification of Living Organisms

• CLASSIFICATION - is the process of arranging organisms

  into groups using similar characteristics.
• TAXONOMY - is the science of describing, naming, and classifying living

  and extinct organisms and viruses.
• Taxonomy derived from the Greek word “taxis” meaning

  arrangement or division and “nomos” means method.
• Taxonomy derived from the Greek word “taxis” meaning arrangement or division and “nomos” means method.
• ARISTOTLE

  • Greek philosopher
  • he classified all the organisms he knew into two groups: plants (bloodless) and animals (with blood).
• Aristotle was the taxonomy's first father;

  sometimes called the “Father of Science."
• TAXONOMIC HIERARCHY - an ordered group of taxonomic rank used to classify organisms from general to specific.
• DOMAIN - is the highest and most general rank of organisms.
• CAROLUS LINNAEUS

  • Swedish naturalist and considered as the 'Father

  of Modern Taxonomy”

  His two most important contributions totaxonomy were:

  • A hierarchical classification system
  • The system of binomial nomenclature
• ARCHAEA - domain contains a single celled organism. They are extreme organisms that live under some of the most extreme environment.
• BACTERIA - single-celled microorganisms that are found in almost every habitat on Earth.
• ARCHAEA BACTERIA (ANCIENT BACTERIA) - are single celled prokaryotes thought to be bacteria, and they are under Archaea domain.
• EUBACTERIA (TRUE BACTERIA) - considered as true bacteria under Bacteria domain.
• PROTISTA - it includes diverse group of organisms, and some have a characteristic of animals(protozoa), others resemble of plants (algae)or fungi.
• PLANTAE - includes all plants important to life that provides oxygen, shelter, clothing and food.
• FUNGI - includes both unicellular (yeast and molds) and multicellular (mushrooms) organisms.
• ANIMALIA - includes animals and they are eukaryotes that depend on plants and other organisms for nutrition.
• PHYLUM / DIVISION - is more specific than kingdom.
• PORIFERA - commonly referred to as sponges.
• CNIDARIA - includes soft-bodied stinging animals such as

  corals, sea anemones, and jellyfish.
• PLATYHELMINTHES - known as flat worms
• NEMATODA - also known as roundworms.
• ANNELIDA - have bodies that are segmented, such as leeches and earthworms.
• ARTHROPODS - they have jointed appendages and a chitinous exoskeleton.
• MOLLUSCA - soft-bodied, non-segmented invertebrates with the body composed of three regions: head, foot and visceral
• ECHINODERMATA - they have a star-like appearance and are spherical or elongated.
• CHORDATA - includes all the vertebrates, i.e., animals with a

  backbone, and several invertebrates, i.e.,

  organisms without a backbone.
• CLASS - is a taxonomic rank above the order and below the phylum.
• ORDER - comprises of families sharing a set of similar nature or character
• FAMILY - is the collection of similar genera.
• GENUS - made up of group of similar species.
• SPECIES - is the lowest and most specific

  level of taxonomic hierarchy.
• EUKARYA - a domain includes eukaryotes or organisms that have membrane–bound nucleus.