Class 8 Science Online NCERT Solutions – Microorganism
Class 8 Science – Chapter 2 – Microorganism : In this article, we will discuss Microorganism for Class 8 Science.
There are a variety of organisms on our planet. The Amoeba is very tiny organism and cannot be seen with our naked eye.
Such extremely tiny organisms can be seen and photographed with the help of an instrument called MICROSCOPE.
MICROSCOPE– A Microscope is an instrument basically used for seeing smaller objects,lenses areused in microscope to make smaller objects to appear larger.
The object to be viewed under the microscope is referred to as the specimen. A microscope has the following parts
- A thin sheet of glass is called a Microscopic Slide.
- A second much thinner sheet of glass is called Coverslip and is placed over the sample.
- The Coverslip protects the microscope’s objective lens by preventing it from coming into contact with the specimen sample.
The basic steps to use a compound microscope are as follows –
- Clean the mirror using a soft and clean cloth, if required.
- Place the slide on the stage.
- Adjust the focus of the eyepiece and the objective lens.
- View the slide through the eyepiece.
Types of Microorganisms
Organisms that are visible only through a microscope are called microorganisms or Microbes.
Microorganisms are found almost everywhere in ice-cold regions, hot springs, deserts, and even inside the bodies of animals and human beings. Some live alone while others grow in groups called colonies. They may be unicellular or multicellular organisms.
Microorganisms can be divided into five major groups:
Bacteria– They are the smallest and oldest organisms on our planet, Bacteria are unicellular organisms. Different bacteria have different shapes: Rod Shaped (Bacilli), Spherical (Cocci), Comma Shaped (Vibrio), and Spiral (Spirilla)
**Lactobacillus and Streptococcus are examples of Bacteria. **
A gram of soil contains about 40 million bacteria.
Protozoa– They are a group of animal-like, unicellular organisms. Amoeba, Paramoecium, and Euglena are examples of Protozoa.
Fungi- They are a group of single-celled or multi-celled organisms. Fungi may be either microscopic and unicellular (Ex. Yeast), or Macroscopic and Multicellular (Ex. Mushrooms and Toadstools).
All Fungi lack chlorophyll and derive their nutrition from decaying matter.
Not all fungi and algae are microscopic. Some are them are quite large like a mushroom.
Algae- They are a group of Simple plant like Organisms that contain chlorophyll. They may be unicellular (EX. Chlamydomonas) or Multicellular (Ex. Seaweeds).
Some unicellular Algae also exists in colonies (Ex. Chlorella and Diatoms).
Viruses- They are so small that they cannot be seen using ordinary compound microscopes. They are usually studied with the help of Powerful Microscopes called Electron Microscopes.
- Viruses are hard to classify as living or non-living as on their own, they show no signs of life.
- They reproduced inside the cells of organisms like Plants, Animals or Bacteria.
Tobacco Mosaic Virus (TMV) and Human Immunodeficiency Virus (HIV) are examples of Viruses.
Flu and Swine Flu are also caused by Viruses.
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