Classification of Living Things The Domains

Classification the process of grouping things according to similarities.

Living vs. Non-Living Living (Biotic) Non-Living (Abiotic) Contain one or more cells Are able to: Respond to stimuli from its surroundings Grow Reproduce Maintain Homeostasis- stable internal living conditions Non-Living (Abiotic) Not made of cells Unable to grow, reproduce, or respond to stimuli.

Classification of Life Living things are split into many different categories called Domains. A Domain is the largest and broadest group of living things There are 3 Domains of Life Archaea Eubacteria Eukarya

The 3 Domains The domains are split up based upon the presence of a nucleus. All EUKARYOTES (cell with a nucleus) are in Domain Eukarya. PROKARYOTES are split into Domain Archaea and Eubacteria. Eu= yes, Pro= no Eukaryotes, yes to nucleus Prokaryotes, no to nucleus

Domain Archaea Archaea means ancient! Prokaryotic cell structure (no nucleus) No cell parts (organelles) Genetic material free-floats in the cell Found in extreme environments ( named “extremophiles”). For example, some are found in animal digestive systems (methanogens), while others are found in very salty places (halophiles), and others are found in extremely hot or acidic places (thermoacidophiles) such as volcanoes. Summary: Domain Archaea is made up of Prokaryotes who are Extremophiles.

Where to Find Extremophiles… Extremophiles live in extreme (places where most life could not exist) conditions. These locations include: Highly acidic regions Extreme cold/hot temperature Hot springs High salt regions Sulfur vents at the bottom of the oceans

Domain Eubacteria Rod Shaped Bacteria Prokaryotic cell structure (no nucleus) No cell parts (organelles) Genetic material free-floats in the cell Three basic shapes Rods Spheres (Coccus) Spirals Summary: Domain Eubacteria is made up of Prokaryotes who do NOT live in extreme places. Sphere Shaped Bacteria Spiral Shaped Bacteria

What is the difference between Archaea and Eubacteria? Simply, the differences are the chemicals that make up the two. For example, Eubacteria have a substance called Muramic Acid in their cell walls, while Archaea do not. Archaea are extremophiles This means they exist where living things “should not be able to live”

Domain Eukarya Members of this domain have only one thing completely in common: They are all Eukaryotes, which means they all have nuclei in their cells! Eukaryote cells are much larger than prokaryote cells. Platypus Protozoa

Domain Eukarya The nucleus of a cell controls the function of a cell and holds all the genetic material for the cell (similar to what the brain does for a body) Organisms in the Domain Eukarya are more complex than the organisms in the Domain Bacteria and Domain Archaea Organisms in the Domain Eukarya include: plants animals fungi protists