Microbial Ecology Do Now: Make a list (on your notes handout) of the things EVERY organism needs to survive. Just 3 things Water Energy Carbon Different organisms get these materials in very different ways but we all get them! The First Organisms The very first organisms that arose on Earth were very simple in structure. We call these simple cells prokaryotes. There are millions of species of prokaryotes alive today, and science has described only % of them! Theyre everywhere!!! This is from a soil sample about 2,000x magnification notice how many different kinds are in such a small space. Some famous prokaryotes Escherichia coli Staphylococcus aureus Helicobacter pylori Cyanobacter sp. Bacillus subtilis Microbes Are Everywhere! Prokaryote: A unicellular organism that lacks a nucleus and all other membrane-bound organelles. Microbe: An organism too small to be seen by the naked eye. Ways they Survive Prokaryotes may be heterotrophs or autotrophs. Heterotroph: an organism that gets carbon from organic molecules produced by other organisms. Heterotrophs are consumers. Autotroph: an organism that uses an energy source (such as light) directly to build organic molecules from inorganic carbon source (usually CO 2 ) Hetero vs. Auto Hetero means different, and auto means self does this make sense, since troph means eat? Hetrotroph and Autotroph refer to how an organism gets carbon. Mycobacterium tuberculosis causes tuberculosis. The cells feed on the lung cells of their hosts. Heterotroph or autotroph? Thyobacilus ferroxidans gets its energy from turning iron (II) oxide into iron (III) oxide. They use the energy they get to take CO 2 from the environment and build sugars and other compounds. Heterotroph or autotroph? How do you get ENERGY? Energy is another critical thing all organisms need access to. The prefix photo indicates an organism gets energy from light. The prefix chemo indicates an organism gets energy from a chemical. Phototroph and chemotroph describe how an organism gets energy: from light, or from chemicals. Burger or Nails? Chemotrophs, which get their energy from chemicals come in two flavors: Organotrophs (like you & I) who break down organic chemicals they take in. Lithotrophs (litho = rock) who break down inorganic substances Only 4 ways to Survive on Earth! Get carbon from food to build molecules Use inorganic carbon (CO 2 ) to build molecules Get energy directly (light) PhotoheterotrophPhotoautotroph Get energy from chemicals ChemoheterotrophChemoautotroph Diatoms are unicellular algae that get carbon from CO 2 in water, and energy from light. What are they? Heres another one Some more varieties What about the Mud? All 4 categories of organisms we just described exist within our sample of sediment. We will learn about, and identify a few of these with our Winogradsky columns. Review Make sure you know the following definitions! Prokaryote Microbe / Microorganism Autotroph Heterotroph Phototroph Chemotroph