Showing posts with label Protista. Show all posts
Showing posts with label Protista. Show all posts

Saturday, July 21, 2012

Kingdom Animalia


          With over 2 million species, Kingdom Animalia is the largest of the kingdoms in terms of its species diversity. But when you think of an "animal", what image comes to mind? While mammals, birds, reptiles, amphibians, and fish are the most familiar to us , over half of all the animal species belong to a group of animals known as arthropods. Arthropods include animals such as centipedes, crabs, insects, and spiders.
             Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and independently. All animals are also heterotrophs, meaning they must ingest other organisms or their products for sustenance.


Kingdom Animalia Characteristics
  • All animals are multicellular, eukaryotic heterotrophs —they have multiple cells with mitochondria and they rely on other organisms for their nourishment.
  • Adult animals develop from embryos: small masses of unspecialized cells
  • Simple animals can regenerate or grow back missing parts
  • Most animals ingest their food and then digest it in some kind of internal cavity.
  • Somewhere around 9 or 10 million species of animals inhabit the earth.
  • About 800,000 species have been identified.
  • Animal Phyla- Biologists recognize about 36 separate phyla within the Kingdom Animalia.

Five kingdom classification

Tuesday, July 3, 2012

Kingdom Fungi

            A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and moulds), as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose.There are about 40 000 different kinds of fungi. 

             
            These are organisms without chlorophyll, have heterotrophic mode of nutrition.Fungi have evolved to use a lot of different items for food. Some are decomposers living on dead organic material like leaves. Some fungi cause diseases by using living organisms for food. These fungi infect plants, animals and even other fungi. Athlete’s foot and ringworm are two fungal diseases in humans. The mycorrhizal fungi live as partners with plants. They provide mineral nutrients to the plant in exchange for carbohydrates or other chemicals fungi cannot manufacture.
             
                   They have wide variety of organisms which range from yeasts, fungi to mushrooms. The branch of science which deals with disease causing fungi is known as Fungal Pathology. Saprotrophic organisms are known as decomposer as their organic food comes from dead and decayed matter.Mycology is the branch of biology which deals with the study of fungi.

Example :

  •  Rust
  • Smut
  • Truffles
  • Mushrooms 
  • Yeast

Saturday, June 9, 2012

Kingdom Protista

      Protists are a diverse group of eukaryotic microorganisms. Historically, protists were treated as the kingdom Protista, which includes mostly unicellular organisms that do not fit into the other kingdoms, but this group is contested in modern taxonomy. Instead, it is "better regarded as a loose grouping of 30 or 40 disparate phyla with diverse combinations of trophic modes, mechanisms of motility, cell coverings and life cycles."
       The protists do not have much in common besides a relatively simple organization either they are unicellular, or they are multicellular without specialized tissues. This simple cellular organization distinguishes the protists from other eukaryotes, such as fungi, animals and plants.Some members of Kingdom Protista are unicellular, others are colonial, and yet others are multicellular. Note that in the colonial forms, all the cells are similar with similar, generalized functions, whereas in the truly multicellular species, the “body” of the organism consists of a variety of types of cells, each type with its own specialized function. These organisms are all eukaryotes (they have a true nucleus). They all need some kind of a water-based environment--which can be fresh or marine water, snow, damp soil, polar bear hairs--in which to live. All are aerobic and have mitochondria to do cellular respiration, and some have chloroplasts and can do photosynthesis. Most of them reproduce or grow by mitosis, and some reproduce by meiosis and fertilization. Many can form cysts in adverse conditions. Protists are a major component of plankton.
                Examples
  • Paramecium
  • Amoeba 
  • Giardia
  • Trichonympha

Friday, June 8, 2012

Five kingdom classification

 Five kingdom classification

This is the five kingdom classification given by scientist Whittaker (1969).This scheme was based on -
  • Structure of Cells - {prokaryotic or eukaryotic }
  • Structure of Organism - {unicellular or Multicellular}
  • Mode of nutrition - Photosynthesis in green plants, absorption in fungi and ingestion in animals. 
  1.  Kingdom Monera
  2.  Kingdom Protista
  3.  Kingdom Fungi
  4.  Kingdom Plantae
  5.  Kingdom Animalia