Chapter 1 Living World and Classification of Microbes Solutions

Scientist

Pattern of classification

1. Carl Linnaeus

(e) 2 kingdoms of living organisms

2. Haeckel

(d) 3 kingdoms – Protista, Plants and Animals.

3. Chatton

(b) 2 groups as Prokaryotes and Eukaryotes

4. Kopland

(c) 4 groups as Monera, Protista, Plants and Animals

5. Whittaker

(a) 5 groups of living organisms

Living organism

Group

1. Clostridium titani

(a) Heterotrophic Protista

2. Paramoecium

(b) Fungi

3. Chlamydomonas

(c) Bacteria belonging to Monera

4. Baker’s yeast

(d) Algae

(e) Virus

Living organism

Group

1. Clostridium titani

(c) Bacteria belonging to Monera

2. Paramoecium

(a) Heterotrophic Protista

3. Chlamydomonas

(d) Algae

4. Baker’s yeast

((b) Fungi

(e) Virus

Microbes

Size

1. Virus

(a) 1 μm to 10 μm

2. Algae

(b) 200 μm

3. Protozoa

(c) 10 μm to 100μm

4. Bacteria

(d) 10 nm to 100 nm

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

Name the following/ Give examples

Answer the following questions in one sentence:

Give answers:

2. Complexity of organisms Whether the organisms are unicellular or multicellular is considered.

3. Mode of nutrition Whether the organism is autotrophic and is performing photosynthesis on its own or it is heterotrophic is considered. Plants are autotrophic, fungi are saprotrophic while animals use food from plants or other animals and hence they are heterotrophic.

4. Lifestyle According to nutrition, every living organism is at certain trophic level. This is called lifestyle. Plants are producers, animals are consumers while fungi are decomposers.

5. Phylogenetic relationship When the evolution proceeded gradually, there was transition from prokaryotes to eukaryotes, unicellular to multicellular. In this order the different groups of living organisms were evolved. This is known as phylogenetic relationship.

Use your brain power!
(Textbook page 3)

II. Demerits of Whittaker’s method of classification:

1. Some organisms belonging to Monera and Protista have ability to perform photosynthesis. Thus they show mode of nutrition as autotrophic, while others are heterotrophic. Similarly some monerans have cell wall and some Protists also have cell wall. This becomes confusing during their placement.

2. In kingdom Protista, organisms show varied characteristics. In spite of this they are placed together.

3. In kingdoms, Plantae, Animalia and Fungi the organisms having primitive characters and were initial examples during evolution are not included. E.g. In Kingdom Animalia, amoeba is not included though it is said to be unicellular animal. This creates confusion.

4. Similarly if algae are unicellular, they are placed in kingdom Protista and if they are multicellular they are placed in kingdom Plantae. In reality, unicellular and multicellular algae both show much similarity. But due to Whittaker’s classification system they are placed away from each other.

5. Species of algae such as Chlorella, Chlamydomonas are not included in Kingdom Protista.

6. Viruses are not included in any of the kingdoms by Whittaker. Their classification has become a point of debate among the biologists.

Write short notes:

E.g. Euglena is autotrophic as it does photosynthesis with the help of 5 chloroplasts present in its body. Amoeba and Paramoecium are heterotrophic and free living seen in contaminated water.

Complete the paragraph using the words given in the brackets

[Monera, Euglena, autotrophic, cell organelles, chitin, nuclear, prokaryotic, viruses, replicas, saprotrophic, viral particles]

In Kingdom ……….. bacteria were included but not ………….. Viruses are on the border line of living and non-living. Do we really call them living? If they are making …………. of their own type, are they not considered as living? Throughout the world they spread hazardous epidemics. Antibiotics do not act on ………… However, bacteria can be controlled by antibiotics. All the living organisms belonging to Monera are with …………… cell. They do not have ………….. membrane and neither they have ……………… But a nice nucleus is seen in …………….., Euglena is ………… protist. The fungi with cell wall of …………….. are ………….. in their mode of nutrition.
Answer:
In KingdomMonerabacteria were included but notviruses.Viruses are on the border line of living and non-living. Do we really call them living? If they are makingreplicasof their own type, are they not considered as living? Throughout the world they spread hazardous epidemics. Antibiotics do not act onviral particles.However, bacteria can be controlled by antibiotics. All the living organisms belonging to Monera are withprokaryoticcell. They do not havenuclearmembrane and neither they havecell organelles. But a nice nucleus is seen inEuglena. Euglena isautotrophicprotist. The fungi with cell wall ofchitinaresaprotrophicin their mode of nutrition.

Complete the chart:

Draw neat and labelled diagrams:

Activity-based questions

1. Try this:
Activity Take a small drop of curd or buttermilk on a clean glass slide. Dilute it with a little water. Carefully keep a coverslip. Observe it under high power of compound microscope. What did you see?
Answer:
In the slide we can see Lactobacilli \ bacteria.

2. Try this:
Activity Prepare a temporary mount of one drop of pond water on a glass slide. Observe it under low power and high power microscope.
Answer:
The drop on the slide shows motile microscopic organisms which have irregular shape. They are amoeba.

3. Try this:
Activity Take a moist piece of bread or bhakri and keep it in a container with lid for 2-3 days. After 2-3 days a fine cotton thread like tuft is found growing on the surface of the bread. Prepare a temporary mount of few threads from this culture and observe it under the microscope.
Answer:
Upon observation of thread like structures the fungal hyphae ( fibre like body) are seen.

MCQs based on experiments:

Choose the appropriate alternative of the following:

Experiment 1: To observe lactobacilli in curd/buttermilk.

Experiment 2: To observe fungus on the bread