Living World and Classification of Microbes - Chapter 1 | Class 8 - Science Solutions

Living World and Classification of Microbes – Chapter 1 | Class 8 Science Solutions – Maharashtra State Board

Q.1: Use Whittaker method to classify bacteria, protozoa, fungi, algae, prokaryotic, eukaryotic, microbes.

Answer:

Bacteria: Kingdom Monera
Protozoa: Kingdom Protista
Fungi: Kingdom Fungi
Algae: If unicellular, Kingdom Protista. If multicellular, Kingdom Plantae
Prokaryotic: Kingdom Monera
Eukaryotic: Any kingdom other than Monera.
Microbes: Kingdom Monera or Protista.

Q.2: Complete Complete the five kingdom method of classification using- living organism, prokaryotes, eukaryotes, multicellular, unicellular, protista, animals, plants, fungi.

Answer:

Q.3: Find out my partner

A	B
Fungi	Chlorella
Protozoa	Bacteriophage
Virus	Candida
Algae	Amoeba
Bacteria	Prokaryotic.

Answers:

A	B
Fungi	Candida
Protozoa	Amoeba
Virus	Bacteriophage
Algae	Chlorella
Bacteria	Prokaryotic.

Q.4. : State whether the following statements are True or False. Explain your statement:

Q. a. : Lactobacilli are harmful bacteria.
Answer: False.
Explanation: Lactobacilli are useful bacteria. They are used for curdling the milk. They are also used for preparing variety of milk products.

Q. b.: Cell wall of fungi is made up of chitin.
Answer: True.
Explanation: The cell wall of the plants is made up of cellulose while the cell wall of fungi is made up of complex sugar called chitin. Inside the fungal cell wall there is cytoplasm which contains many nuclei.

Q. d.: Organ of locomotion in amoeba is pseudopodia.
Answer: True.
Explanation: Amoeba is a protozoan, primitive organism which possesses pseudopodia as the organ for locomotion.

Q. e.: Tomato wilt is a viral disease.
Answer: True.
Explanation: Tomato wilt is a viral disease. These viruses are able to infect only plant cells.

Q.5: Give answers

Q.a. : State the merits of Whittaker’s method of classification.
Answer:
1) Clear Organization: It groups organisms into five kingdoms (Monera, Protista, Fungi, Plantae, Animalia) based on their cell structure, mode of nutrition, and body organization, making it easier to study and understand them.

2) Evolutionary Relationships: It shows the evolutionary relationships between different groups of organisms, helping us understand how life has evolved.

3) Distinct Groups: It clearly separates simple, single-celled organisms from complex, multicellular ones, providing a clear distinction between different forms of life.

4) Broad Acceptance: It is widely accepted and used by scientists around the world, making it a standard method for classifying living organisms.

Q. b. Write the characteristics of viruses.
Answer:

Viruses are extremely minute of the size range of 10 nm to 100 nm and are visible only through the electron microscope. They are on the borderline of living and non-living.
Though they are not considered as living, they can make replica of their own.
They are long molecules of DNA or RNA which are covered by a protein coat.
Their survival is possible only inside the living plant or animal cells. When they infect the host cells, they produce their own proteins with the machinery of the host cell. These proteins form many replicas of the infecting virus and so on they spread in the body.
Most of the viruses are pathogenic, they cause diseases in plants and animals.

Q. c. Explain the nutrition in fungi.
Answer: Most of the fungi are saprophytic in their nutrition. They absorb the nourishment from dead and decaying matter. By taking the organic matter from dead bodies of plants and animals, fungi survive. In this process they degrade the organic matter completely.

Q.d. Which living organisms are included in the kingdom Monera?
Answer:

All the living organisms belonging to Kingdom Monera are unicellular.
The mode of nutrition in them is either autotrophic or heterotrophic.
All of them are prokaryotic and thus they do not have well-formed nucleus. The nuclear membrane and the cell organelles are absent in them.
Kingdom Monera consists of different types of bacteria and blue-green algae.
E.g. Bacteria Clostridium titani, Vibrio choleri, Treponema pallidum, Streptococcus pneumoniae, Legionella pneumoniae, Salmonella typhi, Staphylococcus aureus, Clostridium botulinum.

Q.6: Who am I?

Q. a. I don’t have true nucleus, cell organelles or plasma membrane.
Answer: Microbe from Monera

Q. b. I have nucleus and membrane bound cell organelles.
Answer: Protozoan from Protista/I am any one of Eukaryote

Q. c. I live on decaying organic matter.
Answer: Fungus

Q. d. I reproduce mainly by cell division. (*Binary fission)
Answer: Bacteria and some Protozoa.

Q. e. : I can produce my replica.
Answer: Virus

Q. f. : I am green, but don’t have organs.
Answer: Algae

Q. 7 : Draw neat and labelled diagrams.

Q. a. : Different types of bacteria:
Answer:

Q. b.: Paramoecium:
Answer:

Q. c. Bacteriophage
Answer:

Q. 8.: Arrange the following in ascending order of size Bacteria, Fungi, Viruses, Algae.

Answer: Viruses, Bacteria, Fungi, Algae.

Additional Question Answers :

Q.1 : Rewrite the sentences after filling the blanks:

Q. 1. : The process of dividing living organism into groups and subgroups is called …………… .
Answer: Biological classification.

Q. 2.: In fungi the cell wall is made up of j tough and complex sugar called …………… .
Answer: ‘Chitin’.

Q. 3. : Most of the fungi are …………… .
Answer: Saprotrophic.

Q. 4. Viruses can be seen only with …………… .
Answer: Electron microscope.

Q. 5. Organisms with cell wall but not able to perform photosynthesis are called …………… .
Answer: Fungi.

Q.2. : Find my partners:

Microbes	Size
Virus	(a) 1 μm to 10 μm
Algae	(b) 200 μm
Protozoa	(c) 10 μm to 100μm
Bacteria	(d) 10 nm to 100 nm

Answer:

Microbes	Size
1. Virus	(d) 10 nm to 100 nm
2. Algae	(c) 10 μm to 100 μm
3. Protozoa	(b) 200 μm
4. Bacteria	(a) 1 μm to 10 μm

Q.3. : Name the following

Q. 1. Three organs of locomotion in Protista
Answer: 1. Pseudopodia, 2. Cilia, 3. Flagella

Q. 2. Two autotrophic Protista
Answer: 1. Euglena, 2. Volvox.

Q. 3.: Institute in India which is involved in research on viruses
Answer: 1. National Institute of Virology, 2. Pune

Q. 4. : Two methods of asexual reproduction in Fungi
Answer: 1. Binary fission, 2. Budding

Q. 5. : Two pathogenic protozoans and the diseases caused by them
Answer: 1. Entamoeba histolytica causes amoebiasis,
2. Plasmodium vivax – causes malaria.

Q.4.: Answer in one sentence:

Q. 1. : What are the types of living organisms according to their lifestyle?
Answer: Producers, consumers and decomposers are the types of living organisms according to their lifestyle.

Q. 2. : What are the characteristics of prokaryotic cells?
Answer: Absence of nuclear membrane, well- formed nucleus and lack of cell organelles are the characteristics of the prokaryotic cells.

Q.5.: To observe lactobacilli in curd/buttermilk.

Q. 1.: Which of the following bacterium is used to make curds from milk?
(a) Streptococcus, (b) Lactobacillus, (c) Staphylococcus, (d) Clostridium
Answer: (b) Lactobacillus

Q.2. : In which kingdom is Lactobacillus included?
(a) Monera, (b) Protista, (c) Fungi, (d) Plantae
Answer: (a) Monera

Q. 3.: Which is the other organism that has been added in kingdom Monera in addition to bacteria?
(a) Virus, (b) Blue-green algae, (c) Fungi, (d) Protozoa
Answer: (b) Blue-green algae

Q. 4. : In which kingdom is fungus growing on the bread included?
(a) Fungi, (b) Protozoa, (c) Monera, (d) Protista
Answer: (a) Fungi

Q. 5.: What are dark coloured particles which are seen when the fungus is growing on the bread?
(a) Sporangiophore, (b) Rhizoids, (c) spores, d) Columella
Answer: (c) spores

Q.6. : Write short notes:

Q.1. : Demerits of Whittaker’s method of classification:

Overlapping Groups: Some organisms don’t fit neatly into any of the five kingdoms, making classification difficult.
Genetic Differences: It doesn’t consider genetic information, which is important for understanding relationships between organisms.
Simplistic: It may be too simplistic for some complex organisms, not showing all their unique characteristics.
Evolutionary Relationships: Sometimes, it doesn’t accurately show the evolutionary relationships between certain groups of organisms.
Species of algae such as Chlorella, Chlamydomonas are not included in Kingdom Protista. Viruses are not included in any of the kingdoms.

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Living World and Classification of Microbes – Chapter 1 | Class 8 – Science Solutions