Why classification?

1. study a large number of organisms in a systematic way
2. identify an organism more easily by matching it with the characteristics of one of the groups
3. understand the evolutionary histroy of organisms
4. make predictions

Classifying

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Binomial nonmenclature

Classification system

• versions

  • 2 kingdoms: animalia, plant
  • 3 kingdoms: + protista
  • 4 kingdoms: + prokaryota
  • 5 kingdoms: + fungi
  • 6 kingdoms: prokaryota --> archaebacteria, eubacteria
  • 3 domains: bacteria, archaea, eukarya
    
    

• based on evolutionary history

• study of the genetic material: more similar the genetic material between two groups, the closer their phylogenetic relationship

• classification system keeps changing over time

• new system is established when new evidence arises/ different classification criteria are used by different scientists.

• Organisms with closer phylogenetic relationship are put closer together

Six kingdoms

• Eubacteria
• Archaebacteria
• Protista
• Fungi
• Plantae
• Animalia

Eubacteria

• aka, bacteria
• very small, 1-5µm, only seen under high-power
• unicellular prokaryotes
• cell wall made of peptidoglycan
• some have hair-like flagellum for locomotion
• some enclosed by capsule
• rod-shaped, spherical, spiral
• some cause diseases, while some are important in the cycling of materials in the ecosystem

Archaebacteria

• unicellular prokaryotes, even smaller
• more closely related to eukaryotes than to bacteria
• cell walls, unique composition
• lipid in cell membrane is different
• live in extreme environments

Protista

• aka, protists
• eukaryotes, unicellular
• live in water
• groups:
  • protozoans: animal-like (movement)
  • algae: plant-like (photosynthesis)
  • slime mould: fungus-like

Fungi

• multicellular
• made of hyphae --> interweave to for mycelium
• cell wall: not cellulose
• no chlorophyll
• spores for reproduction
• saprophytic;
• parasitic

Plantae

• aka, plants
• Autotrophs
• cell walls, cellulose
• Types
  • Non-vascular
  • Vascular

Non-vascular

• no vascular tissues
• small, grow in shady and damp places
• simple stems and leaves, no true roots
• rhizoids for anchorage, abs. of water and minterals
• chlorophyll
• spores
• e.g. mosses

Vascular

• true roots, stems and leaves
• can live in dry places
• types
  • Ferns
  • Conifers
  • Flowering plants

i. Ferns

• large and feathery leaves, young are curled
• spores under side of the leaves for reproduction

ii. Conifers

• trees with needle-shaped leaves
• naked seeds for reproduction: not enclosed in fruits, found in cones

iii. Flowering plants

• flowers for reproduction, seeds formed inside fruits
• Two types
  • monocotyledonous plants(monocots),
  • dicotyledonous plants(dicots)

	no. of seed leaves	Leaf venation	no. of petals
Monocots	1	Parallel venation	3n
Dicots	2	Net venation	4n/5n

Animalia

• Animals
• Heterotrophs
• no cell wall
• move freely from place to place
• types
  • vertebrates
  • invertebrates

Invertebrates

• No backbones
• e.g.
  • Jellyfish:
    • tentacles with sting cells
    • 1 body opening = anus = mouth
  • Earthworm:
    • tube-like soft body with segments
    • chaetae on ventral side --> mvt
  • Snail:
    • soft body, shell
    • flattened musclar foor
  • Sea Urchin:
    • spines, tube feet
  • Ant:
    • insect: head, thorax, abdomen
    • exoskeleton
    • 3 pairs of joined legs, compound eyes, antennae
  • Crab:
    • hard exoskeleton
    • gills

  Vertebrates

  • Fish
    • Wet, slimy scales
    • gills, fins
    • external fertilization, in water
    • poikilotherms
  • Amphibians
    • Lungs, skin surface
    • moist naked skin
    • 4 limbs
    • external fertilization, in water
    • poikilotherms
  • Reptiles
    • lungs
    • dry, hard scales
    • 4 limbs
    • internal fertilization
    • eggs with leathery/hard shells
    • poikilotherms
  • Birds
    • lungs
    • wings, feathers, beak
    • dry scales on legs
    • internal fertilization
    • eggs with hard shells
    • homiotherms
  • Mammals
    • lungs
    • hair
    • pinnae
    • mammary glands: females produce milk to feed their young
    • internal fertilization
    • homiotherms