Main Biology II Page | Syllabus | Notes | Practice Tests

Biology II Notes

The Six Kingdoms

     The latest research divided all living things into 6 kingdoms.  The newest is Archaebacteria.  These bacteria were considered to be so different from the other bacteria, they deserved their own kingdom.

Archaebacteria - Eubacteria - Protista - Fungi - Plantae - Animalia

     The Archaebacteria are organized into three phyla of bactreria that are found mainly in extreme habitats where little else can survive. All known Archaebacteria live without oxygen(anerobic) and obtain their energy from inorganic molecules or from light. The following is some basic information on the three phylum.
        1. Methanogens: This type of bacteria produces methane. Many such species live in the intestines of animals. They help breakdown food in the intestines and also provide essential nutrients. In return, the bacteria get a source of energy. This is an example of a mutualistic symbiotic relationship, which is when two organisms work together to survive.
        2. Halophiles: This type of bacteria can only live in bodies of concentrated salt water. such as the Great Salt Lake (Utah) and the Dead Sea (Middle East). 
        3. Thermoacidophiles: A third phylum includes bacteria that are found in the hot, acidic waters of sulfur springs. These  species can handle temperatures near 80 degrees Celcius and pH levels as low as 2. 

     Eubacteria, the second group of Monerans, make up their own Kingdom.They live in a wide variety of habitats and obtain their energy needs in a variety of ways. The main phylum are orgainzed by how they obtain energy.
        1. Heterotrophs: This type of bacteria is found just about everywhere. These bacteria need organic molecules as an energy source but are not adapted for trapping the food that contains these molecules. Thus, some live as parasites, absorbing nutrients from living organisms. Others live as saprobes, organisms that feed on dead organisms or organic wastes. Saprobes help recycle the nutrients from decomposing organisms back into the environment, so those nutrients can be used for new or existing life.
        2. Autotrophs: These bacteria are photosynthetic autotrophs. An autotroph is an organism that can make its own food. This is done through photosynthesis, a process that uses the suns energy to make sugar molecules. Most Cyanobacteria are blue-green in color, which is why they are often called blue-green bacteria. They are common in ponds, lakes,streams and moist areas of land. They are composed of chains of bacteria cells, an exception to the rule that Monerans are unicellular. These chains and the existence of chlorophyll (photosynthetic pigment) help provide evidence for bacteria being the ancestors of plants.
        3. Chemotrophs: The third phylum is the chemosynthetic autotrophs. These bacteria obtain their energy from chemosynthetic breakdown of inorganic (nonliving matter - no carbon) substances such as sulfur and nitorgen compounds. Some of these bacteria are important in converting nitrogen in the atmosphere to forms that can be used by plants.

     Protists are single and multicellular organisms that are plant-like, animal-like and fungi-like. They evolved from bacteria and represent the intermediate step in the evolution of the other three kingdoms. There are 12 phyla in this kingdom, most of which live in water. 
     Below is a list of the 12 phyla which are organized into three groups; plant-like, animal-like and fungi-like. The links are the scientific name, while the common name is in parentheses. 

I. Plant-like Protists (Algae) - 6 phyla           
      Euglenophyta (Euglenas) 
      Chrysophyta (Diatoms) 
      Pyrrophyta (Dinoflagellates) 
      Chlorophyta (Green Algae) 
      Rhodophyta (Red Algae) 
      Phaeophyta (Brown Algae)
II. Animal-like Protists (Protozoa) - 4 phyla
      Sarcodina (Sarcodines) 
      Mastigophora (Flagellates) 
      Ciliophora (Ciliates) 
      Sporozoa (Sporozoans)
III. Fungus-like Protists - 2 phyla
      Myxomycota (Slime molds) 
      Oomycota (Water Molds & Mildews)

     Fungi are many-celled organisms that decompose dead matter in our environment. Thus, they are Consumers and a very important one. Fungi and bacteria are responsible for doing the major cleaning role in our environment. In fact, they are in competition with one another for materials to decompose. Fungi are found in soil, dead trees and even on your bread sometimes.
     There are four phylum in the Fungi Kingdom.

     Plants are many-celled organisms that are characterized by their tough cell walls and photosynthetic abilities. That is, they use a pigment called chlorophyll that can take sun light energy and convert it into food energy or sugar. Because plants can make their own food, they are know as Producers. The food chain begins with Producers, who supply food for the Consumers of the world. Nearly 300,000 plants have been identified and their environments range from the deep ocean to mountain tops. Plants most likely evolved from plant-like protists about 420 million years ago. 
     The Nine Divsions Of The Plant Kingdom 
        4 divisions of Seedless Plants: 
          Bryophyta (Mosses and Liverworts) - 20,000 species
          Sphenophyta (Horsetails) - 15 species
          Lycophyta (Club mosses) - 1,000 species
          Pterophyta (Ferns) - 12,000 species 
        5 divisions of Seed Plants
          Angiosperms (flowering Plants) - vascular plants that produce seeds that are enclosed inside a fruit.
               Anthophyta (monocots and dicots) - 250,000 
          Gymnosperms (Naked Seed)mnosperms - vat produce seeds onclcones.
               Coniferophyta - 550 species
               Ginkophyta - 1 species
               Cycadophyta - 100 species
               Gnetophyta - 70 species

     The Animal Kingdom is very diverse and very large, numbering over one million identified species. Some are vertebrates(backbone), while most (97%) are invertebrates(no backbone). All animals share the following characteristics; cannot make own food, digest their food, move from place to place, and have many Eukaryotic cells. Animals are classified into nine major phyla. 
     Sponges : Porifera
     Cnidarians : Cnidaria
     Flatworms : Platyhelminthes
     Roundworms : Nematoda
     Mollusks : Molluska
     Annelids : Annelida
     Arthropods : Arthropoda
     Echinoderms : Echinoderm
     Chordates : Chordata

Main Biology II Page | Syllabus | Notes | Practice Tests