TOPIC 4: CLASSIFICATION OF LIVING THINGS
Concept of Classification
Major Groups of Living Things
Viruses were discovered by a Russian botanist D. I. Ivanovsky and a Dutchman Beijerink. In 1852 Ivanovsky prepared an infectious extract from tobacco plants that were suffering from mosaic disease. When the extract was passed through a filter able to prevent the passage of bacteria, the filtered fluid was still infectious. 1898 Beijerink gave the name “virus” (in latin means, “poison”) to describe the infectious nature of certain filtered plant fluids.
Phyla of the Kingdom Protoctista
Mention phyla of the kingdom protoctista
The phyla of kingdom protoctists include the following:
- Euglenophyta e.g. Euglena
- Rhizopodia e.g. Amoeba
- Zoomastigma e.g. Trypanosoma
- Apicomplexa e.g. Plasmodium
- Oomycota e.g. White root
- Chlorophyta e.g. Spyrogyra
- Cilliaphora e.g. Paramecium
- Rhodophyta e.g. Red algae
Structure of Amoeba and Paramecium
Describe structure of amoeba and paramecium
Amoeba belong to phylum Rhizopoda, organisms with the following extra features:
- They are eukaryotes
- They move using pseudopodia
Pseudopodia are projection of the cytoplasm that extend and pull the amoeba forward or engulf food particles.
The Advantages and Disadvantages of Amoeba, Euglena Paramecium and Plasmodiu
Explain the advantages and disadvantages of amoeba, euglena paramecium and plasmodium
Advantages of Paramecium: Are eaten by small water animals
Disadvantages of Paramecium: Causes diseases of bulanterdium eoli destroying the lining of intestines
Osmoregulation:Paramecium has two contractile vacuoles and each is associated with permanent system of collecting channels, which empty, into the main vacuole.
Feeding: Paramecium feed on bacteria. These are obtained from the surrounding water by the beating of the cilia-lining o the oral grove.
Reproduction:Paramecium reproduces both asexually and sexually. The asexual method is more common and it is binary fission. Sexual method is called conjugation.
Movement in paramecium is caused by cilia beating. This movement is called cilliary movement.