Domains and Kingdoms of Life Notes

Domains and Kingdoms of Life

• All living things are sorted into one of the 3 DOMAINS of life: Bacteria, Archaea, and Eukarya.
• These domains encompass 6 KINGDOMS: Bacteria, Archaea, Protists, Plants, Fungi, and Animals.

Taxonomy

• The taxonomy of living things is hierarchical and includes:
  • Domain (e.g., Eukarya)
  • Kingdom (e.g., Animalia)
  • Phylum (e.g., Chordata)
  • Class (e.g., Mammalia)
  • Order (e.g., Primates)
  • Family (e.g., Hominidae)
  • Genus (e.g., Homo)
  • Species (e.g., Sapiens)
• Example: Humans are classified as Homo sapiens.

Domain Bacteria

• Contains all bacteria.

Domain Archaea

• Contains all archaea.

Domain Eukarya

• Contains all living things that are not bacteria or archaea.

1. Kingdom Archaea

• Considered the first life forms.
• Cell walls are present but do not contain peptidoglycan.
• Can be autotrophic, heterotrophic, and decomposers.
• Prokaryotes: lack a nucleus.
• Unicellular: single-celled organisms.
• Some possess flagella and cilia for movement.
• Reproduce asexually via binary fission.
• Live in harsh environments:
  • Thermophiles: thrive in extreme temperatures.
  • Methanogens: live in methane-gas rich areas.
  • Halophiles: live in salty areas.

2. Kingdom Eubacteria

• Prokaryotes: lack a nucleus.
• Unicellular.
• Newer forms of bacteria compared to Archaea.
• Cell walls contain peptidoglycan.
• Most are heterotrophs, but some are autotrophs (cyanobacteria).
• Reproduce asexually through binary fission.
• Examples:
  • Cyanobacteria (blue-green algae): an autotroph.
  • E. coli, Streptococcus, and other common bacteria.

3. Kingdom Protista

• Eukaryotes: have a nucleus and membrane-bound organelles.
• Mostly unicellular, but a few are multicellular.
• Some reproduce sexually, but most reproduce asexually.
• Obtain nutrition in various ways: can be heterotrophs or autotrophs.
• Referred to as the “junk drawer” kingdom because it includes organisms that don't fit neatly elsewhere.
• Move using cilia, flagella, or pseudopodia.
• Types:
  • Plant-like: have cell walls and are autotrophs.
  • Animal-like: are heterotrophs.
  • Fungi-like: are heterotrophs.
• Examples: Amoeba, Paramecium, Kelp (brown algae), Slime Mold.

4. Kingdom Fungi

• Eukaryotes: cells with a nucleus and membrane-bound organelles.
• Mostly multicellular; some are unicellular (e.g., yeast).
• Cell wall made of chitin (not a typical cell wall).
• Heterotrophs and decomposers.
• Cannot move.
• Have both sexual and asexual reproductive cycles.
• Examples: molds, yeast.

5. Kingdom Plantae

• Eukaryotes.
• All are multicellular.
• Cell wall made of cellulose.
• Autotrophs: producers with chloroplasts.
• Reproduce sexually and asexually.
• Two main groups:
  • Monocots:
    • One cotyledon.
    • Parallel leaf venation.
    • Fibrous root system.
    • Vascular bundles usually complexly arranged.
    • Floral parts usually in multiples of 3.
  • Dicots:
    • Two cotyledons.
    • Netlike leaf venation.
    • Taproot usually present.
    • Vascular bundles usually arranged in a ring.
    • Floral parts usually in multiples of 4 or 5.
• Examples: mosses.

6. Kingdom Animalia

• Eukaryotes.
• All are multicellular.
• No cell wall.
• Heterotrophs (consumers).
• Reproduce sexually.
• Examples: sponges, sea anemones, jellyfish, worms, mussels, squid, octopus, shrimp, starfish, sea urchins, reptiles, birds, mammals, amphibians, fish.

Viruses

• Not categorized into any kingdom because they are not considered alive.
• Not dead either, because they were never alive.
• Considered non-living.
• Contain either DNA or RNA.
• Capsid is made from protein.
• Envelope is made from phospholipids (obtained from the host).
• Viruses Do:
  • Have DNA or RNA
  • Have Organization
  • Adapt and Evolve
• Viruses Don’t:
  • Grow
  • Have Cells
  • Reproduce without a host
  • Respond to their environment (perform homeostasis)
  • Make energy