Archaea – The beginning Do Now: Read the article “Introduction to the Archaea” Why are they life’s extremists?

The 3 domain system

How Classification Works Each domain is further divided into kingdoms, which are then divided into phyla, etc. etc. The hierarchy of classification is on your notes It can be remembered with a simple mnemonic device: Kinky People Cry Out For Good Sex Kingdom Phylum Class Order Family Genus Species

Big Differences Strangely, eukaryotes have more in common with archaea than with bacteria! Archaea are the organisms alive today that most resemble the first cells that arose on Earth rRNA sequences – since every organism has them – are used to determine evolutionary relationships (more similar sequence = more recent ancestor)

Archaea are the producers of hydrothermal vent communities Where life began? Similar to archaea. Chemoautotrophs

Deep-Sea Hydrothermal Vent

Archaea from the Deep! CHEMOAUTOTROPHS

How Domains are Defined Bacteria and Archaea are prokaryotes; Eukayra is the only domain of Eukaryotes The 3 domains have chemical differences in cell membrane lipids There are numerous other differences between the three, including what antibiotics kill them.

Domain Archaea Most are extremophiles: organisms which survive in extreme environments, including Thermophiles: high temperatures Thermoacidophiles: high temps & low pH Halophiles: high salt Hyperthermophiles: extreme high heat (121oC)

Use the Roots!!! Fill out the word root meanings on your notes! Use them to decode the meanings of the different types of archaea. Where would a halothermophile live? A hyperacidophile?

What you need to Know Name the three domains of life, and identify the two domains of prokaryotes. Identify the domain which is most similar to the common ancestor of all life (archaea) Explain how organisms are classified today (rRNA similarity) Use word roots to determine where groups of archaea live or what they do