Hello I'm Milo for About.com and today we're talking about the six kingdoms of life, using information from About.com's Biology site.For a couple thousand years thinkers have been working on systems for classifying the different types of living organisms and elements in our world.The more we discover, the more ways of talking about organisms we get. For instance we now have three domains based on the molecular building blocks of life, called RNA. All bacteria fall into one of the first two domains: Archaea and Bacteria, and everything else falls into the third domain: Eukarya.So within these three domains there are 6 kingdoms. Archaebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia. Organisms are placed into these categories based on similarities or common characteristics. Some of the characteristics that are used to determine placement are cell type, metabolism, and reproduction.Archaebacteria have been discovered in some of the most extreme and toxic environments on Earth such as hydrothermal vents. Like many single-cell organisms, they reproduce asexually through binary fission, budding, or fragmentation.Eubacteria, the name means true bacteria. Their nutrition comes from absorption photosynthesis, or chemosynthesis.Protista include amoebae, green algae, brown algae, and slime molds among others. They survive on absorption, photosynthesis, or ingestion.Fungi, this group includes: Mushrooms, yeast, and moldsTheir Nutrition comes through absorption.Plantae, this group also includes trees, herbs, and bushes as well as the organisms listed here. Their main source of food comes from photosynthesis.Animalia include a wide range of organisms such as mammals, amphibians, sponges, insects, and worms.For more information on science and biology, check us out at About.com.