The Three Domains Classification in Biology © J Beauchemin 2006

All living things can be classified as either… 1. Archaea 2. Bacteria 3. Eukarya

This diagram shows the relationships between many different types of organisms. This diagram shows the relationships between many different types of organisms. Where do humans fit in? Are we a major part of the tree of life? Where do humans fit in? Are we a major part of the tree of life?

Archaea Prokaryotes (do not have nuclei) Prokaryotes (do not have nuclei) Unicellular; cell wall present Unicellular; cell wall present The piece “archae-” means… The piece “archae-” means… –Old/ ancient –These are similar to the first living things on Earth! First discovered in the 1970’s First discovered in the 1970’s These organisms look like bacteria but their genes are very different These organisms look like bacteria but their genes are very different

Archaea They are known as They are known asEXTREMOPHILES! Extremo = extreme Extremo = extreme Phile = loving Phile = loving These organisms LOVE EXTREME environments such as… These organisms LOVE EXTREME environments such as… Hot Springs (thermophiles) Deep Sea (halophiles)

Archaea Hot springs Deep sea vents

Bacteria Like Archaea, these are unicellular prokaryotes with cell walls Like Archaea, these are unicellular prokaryotes with cell walls May be aerobic or anaerobic… meaning? May be aerobic or anaerobic… meaning? –Aerobic needs O 2, anaerobic does not Bacteria are named based on their shapes… Bacteria are named based on their shapes…

Bacteria Other Helical, comma- shaped, corkscrew- shaped CocciSphere-shapedBacilliRod-shaped

Eukarya Unicellular or multicellular Unicellular or multicellular –Multicellularity is unique to the Eukarya Eukaryotes: cells have nuclei Eukaryotes: cells have nuclei Inside of cells are highly organized Inside of cells are highly organized Sexual reproduction Sexual reproduction –Genetic variation fuels evolution Broken down into four kingdoms Broken down into four kingdoms

Eukarya: Protists The Kingdom Protista is a mixed group The Kingdom Protista is a mixed group Unicellular or multicellular Unicellular or multicellular Varied cell structure Varied cell structure Examples: Examples: Ameba Algae

Eukarya: Fungi The Kingdom Fungi include mostly multicellular organisms The Kingdom Fungi include mostly multicellular organisms Cells have cell walls Cells have cell walls Includes… Includes… moldsmushrooms

Eukarya: Plants The Kingdom Plantae includes vascular and nonvascular plants The Kingdom Plantae includes vascular and nonvascular plants –Vascular plants have roots, stems and leaves All plant cells have cell walls All plant cells have cell walls Includes: Includes: mosssunflowers

Eukarya: Animals The Kingdom Animalia includes multicellular organisms with no cell walls The Kingdom Animalia includes multicellular organisms with no cell walls Examples: Examples: snail lionfish black bear

Summary!

Ribosomes: little dots/ these make proteins Ribosomes: little dots/ these make proteins DNA: genetic material DNA: genetic material Flagellum: tail that helps it move Flagellum: tail that helps it move Cell wall: protects the cell Cell wall: protects the cell

Plasma membrane: holds the cell together Plasma membrane: holds the cell together Nucleus: holds the DNA/ brain of the cell Nucleus: holds the DNA/ brain of the cell