BIOLOGY O LEVEL(FORM ONE) NOTES – CLASSIFICATION OF LIVING THINGS

CLASSIFICATION OF LIVING THINGS

1. There are millions of livings things in the world, grouping them make it easy to study and identify them.
2. Scientific names enable scientist to identify organisms easily, no matter which part of the world they are in.
3. It easier to study organisms in a group, because the members of a group have many things in common.
4. Classification enables scien
   tists to make predictions.
5. It provides an organized system in which newly identified similar organism can be fitted in future
6. It helps man arrange the information about living organisms in an orderly manner to avoid confusion.

1. Artificial classification
2. Natural classification

• It straight forward and easy to use
• It can be done very fast
• Artificial classification is less costly than natural.

1. It gives a lot of information of living things
2. It is most accurate
3. It is universal
4. It avoids confusion

1. It requires a lot of time
2. It needs high skills
3. It is difficult to classify
4. It is expensive
5. It is not stable.

1. Artificial is not accurate and natural is most accurate
2. Artificial is cheap while natural is expensive
3. Artificial classify living organism according to the external features while natural classification classify living organism according to the internal features.

1. Kingdom animalia eg. Cow, cockroach
2. Kingdom plantae eg. Maize tree, peas
3. Kingdom monera eg. Bacteria
4. Kingdom protoctista eg. Amoeba
5. Kingdom Fungi eg. yeast

1. Kingdom
2. Phylum or Division
3. Class
4. Order
5. Family
6. Genus

1. The generic name is written before the specific name
2. The generic name must start with capital letter.
3. The specific name is written in small letter
4. In publisher document such as books scientific name is written in italics eg, Zea mays and Homo sapiens when hand written or typed the names should be underlined.

• Viruses do not grow, feed, excrete or respire. Viruses exist in a dormant state when outside a host cell.

• A virus particle outside a host cell is called a virion. The virion attacks and cause diseases.
• Viruses are host specific, this means that a certain type of virus only attacks a certain host for example. The viruses affect only certain type of white blood cell in human being.

1. Viruses are pathogens, they cause disease and infections such as rabies, muscles, chickenpox and polio also they destroy living cell.
2. They can reproduce very fast, leading to large scale epidemics.
3. Viruses can attach themselves often and this become difficult to destroy for example there are many different types of viruses that cause the common cold and influenza. This makes it difficult to develop vaccines or cures for these infections.

1. They are prokaryotic.
2. They are unicellular, some bacteria stick together to form chain or clusters called colonies.
3. Some are free – living while others are parasites or saprophytes. Free living bacteria are those which exist on their own for example in sewage or soil. Parasitic bacteria are those which live on other organism and get their food from them for example in human beings and animals.

4. Free living bacteria have flagella for movement.
5. Bacteria have a slimy outer layer. This layer helps to protect the bacteria
6. They produce either asexually by binary fission or through spores or sexually through conjugation.
7. Bacteria occur in various shapes.

A bacterium consists of nucleic materials suspended in the cytoplasm. (no nucleus)

The cytoplasm is enclosed by fold cell membrane; a cell wall and slim layer enclose the cell membrane.

These are hair like structure found on the surface of the bacteria. The hairs attach themselves to the host to that they cannot be removed easily for example. Escherichia coli produce fimbria that attaches themselves the living of the urinary track or the intestines.

1. Some non – pathogenic bacteria feed on substance that are harmfully to the environment and in the process neutralize them, for example, they neutralize petroleum waste from petroleum industries, disease and pesticide there by making the environment safe.
2. Bacteria such as rhizobium that are formed in the root nodules of leguminous plants, clostridium and Azotobacter help to convert atmospheric nitrogen to nitrates, plant need nitrate for their growth.
3. Bacteria in the stomach of ruminant animals such as goats and cows secret enzyme that help in the digestion of cellulose which forms a large part of the body of ruminant.
4. Bacteria in the animal gut manufacture vitamins K and B
5. Lactic acid bacteria produce lactic acid as a result of fermentation of carbohydrates. This is important in the production of fermented food and alcoholic drinks.
6. Autotrophic bacteria carry out photosynthesis.

1. Bacteria that neutralize harmfully substance help clean the environment.
2. Bacteria found in the gut help animals to digest food and break it down into a form that can be absorbed into the body.
3. Vitamins produced by bacteria are important for the health of animals include man.
4. Fermentation is used in the production of yoghurt,vinegar and alcohol.
5. Controlled fermentation is used in the curing tea and tobacco and retting of flax, help to treat and preserve these products

6. Some bacteria are used to produce antibiotics which are used to treat bacterial infections.
7. During photosynthesis autotrophic bacteria release oxygen into the atmosphere, oxygen in vital for the respiration in all living things.

1. Bacteria cause infection and disease in animal some of these are fatal.
2. A bacteria disease in crop cause decrease production and losses to farmers.
3. Bacteria cause food to decay and spoil
4. Due to Denitrifying bacteria in the soil convert nitrates to nitrogen. This reduces the nutrients available of plants.

1. They are eukaryotic.
2. Most are unicellular organisms. Only a few are multicellular.
3. Most live in or near water or in moist places.
4. Some are autotrophic (produce their own food) while others are heterotrophic (obtain nutrients from other organisms)
5. Some are mobile while others are stationery.
6. Some reproduce sexually and other asexually.
7. Many of them have locomotory structures such as cilia and flagella.

1. Amoeba has two layers of cytoplasm the outer layer called ectoplasm and the inner layer is called endoplasm.

2. Amoeba is aquatic. They can be found in fresh water.
3. They use pseudopodia (cell extensions) for locomotion and to engulf food particles.
4. Contractile vacuoles regulate the amount of water in the fresh water amoeba.
5. A temporally food vacuole is formed to hold and digest food particles.
6. Waste products such as urea and ammonia are excreted by simple diffusion.
7. Oxygen and carbon dioxide are exchanged by simple diffusion.
8. Amoeba reproduce by binary fission

1. They are unicellular.
2. They are parasitic, with very complex life cycles involving the host and the vector
3. They produce sexually in the vector and asexually when a plasmodium enters the human body. It attacks the red blood cells and the liver.

Euglena are characterized by the green scum that appears on stagnant water

1. They are unicellular.
2. They are found on both fresh water and salt water
3. Euglena move using flagella.
4. Some have chloroplasts for photosynthesis while others are heterotrophs.
5. They reproduce asexually
6. Some euglena have pellicle, the pellicle is flexible layer within the cell membrane. The pellicle helps euglena to change shape.

1. They are unicellular and shipper – shaped.
2. Paramecia are heterotrophic.
3. They live in water
4. They use cilia to move
5. Their bodies are covered with a pellicle
6. Food enters the organism through an open called the oval groove.
7. Paramecia feed on bacteria and microorganisms.
8. They reproduce either sexually or asexually
9. Contractile vacuoles regulated the amount of water in the cytoplasm.