CLASS ELEVEN BIOLOGY CHAPTER 2 BIOLOGICAL CLASSIFICATION QUESTIONNAIRE PART 1

CLASS ELEVEN BIOLOGY CHAPTER 2 BIOLOGICAL CLASSIFICATION QUESTIONNAIRE FOR TESTS AND REVISION.

It can be used as reference material for competitive exams also.

PART 1

1.     Why did early humans classify living organisms?

A: Early humans classified living organisms instinctively to use them for food, shelter, and clothing.

2.     Who was the earliest to attempt a more scientific basis for classification of living organisms?

A: Aristotle was the earliest to attempt a more scientific basis for classification.

3.     How did Aristotle classify plants?

A: Aristotle classified plants into trees, shrubs, and herbs based on simple morphological characters.

4.      How did Aristotle classify animals?

 A: Aristotle divided animals into two groups: those which had red blood and those that did not.

5.     What system of classification was developed during Linnaeus' time?

 A: A Two Kingdom system of classification was developed during Linnaeus' time, which included Plantae and Animalia kingdoms.

6.     What were the limitations of the Two Kingdom system of classification?

A: The Two Kingdom system did not distinguish between eukaryotes and prokaryotes, unicellular and multicellular organisms, and photosynthetic (green algae) and non-photosynthetic (fungi) organisms.

7.     Why was the classification of organisms into plants and animals found to be inadequate?

 A: A large number of organisms did not fall into either the plant or animal category, making the two-kingdom classification inadequate.

8.      Besides gross morphology, what other characteristics were felt necessary to include for classification?

A: Other characteristics like cell structure, nature of the wall, mode of nutrition, habitat, methods of reproduction, and evolutionary relationships were felt necessary for classification.

9.     What has remained constant under all different classification systems?

A: The plant and animal kingdoms have remained constant under all different classification systems, though the understanding of what groups should be included under these kingdoms has changed.

10.  Who proposed the Five Kingdom Classification and in what year?

 A: R.H. Whittaker proposed the Five Kingdom Classification in 1969.

11.  What are the five kingdoms defined by Whittaker?

A: The five kingdoms defined by Whittaker are Monera, Protista, Fungi, Plantae, and Animalia.

12.  What were the main criteria used by Whittaker for classification?

A: The main criteria used for classification included cell structure, body organization, mode of nutrition, reproduction, and phylogenetic relationships.

13.  What system divides the Kingdom Monera into two domains?

A: The three-domain system divides the Kingdom Monera into two domains, leaving the remaining eukaryotic kingdoms in the third domain.

14.  How many kingdoms are there in the three-domain system?

A: There are six kingdoms in the three-domain system.

15.  What unified all organisms in the plant kingdom in earlier classifications?

 A: The presence of a cell wall in their cells unified all organisms in the plant kingdom.

16.  Give an example of unicellular and multicellular organisms being grouped together in earlier classifications.

A: Chlamydomonas (unicellular) and Spirogyra (multicellular) were placed together under algae.

17.  What characteristic difference in cell walls was not considered in earlier classifications?

A: The difference between fungi having chitin in their walls and green plants having a cellulosic cell wall was not considered.

18.  Why were fungi placed in a separate kingdom in Whittaker's classification?

A: Fungi were placed in a separate kingdom because they are heterotrophic and have chitin in their cell walls, unlike autotrophic green plants which have a cellulosic cell wall.

19.  Which kingdom includes all prokaryotic organisms in Whittaker's classification?

 A: Kingdom Monera includes all prokaryotic organisms.

20.  Which kingdom includes unicellular eukaryotic organisms in Whittaker's classification?

A: Kingdom Protista includes unicellular eukaryotic organisms.

21.  What change did Kingdom Protista bring in the classification of organisms?

A: Kingdom Protista brought together unicellular eukaryotic organisms like Chlamydomonas and Chlorella (earlier placed in algae within plants) with Paramoecium and Amoeba (earlier placed in the animal kingdom).

22.  What is the goal of evolving classification systems over time?

A: The goal is to develop a classification system that reflects morphological, physiological, and reproductive similarities, as well as phylogenetic (evolutionary) relationships.

23.  Which kingdom do bacteria belong to?

A: Bacteria belong to the Kingdom Monera.

24.  How abundant are bacteria?

A: Bacteria are the most abundant microorganisms.

25.  Where can bacteria be found?

A: Bacteria can be found almost everywhere, including in soil, extreme habitats like hot springs, deserts, snow, and deep oceans, and as parasites living in or on other organisms.

26.   What are the four categories of bacteria based on their shape?

A: The four categories of bacteria based on their shape are the spherical Coccus (pl.: cocci), the rod-shaped Bacillus (pl.: bacilli), the comma-shaped Vibrium (pl.: vibrio), and the spiral Spirillum (pl.: spirilla).

27.  What does it mean if bacteria are autotrophic?

A: If bacteria are autotrophic, they synthesize their own food from inorganic substrates.

28.  What are the two types of autotrophic bacteria mentioned in the passage?

A: Photosynthetic autotrophic and chemosynthetic autotrophic.

29.  What does it mean if bacteria are heterotrophic?

A: If bacteria are heterotrophic, they depend on other organisms or on dead organic matter for food.

30.  What is the vast majority of bacteria in terms of their nutritional mode?

A: The vast majority of bacteria are heterotrophs.

31.  What makes these bacteria special in terms of their habitats?

 A: These bacteria are special because they live in some of the most harsh habitats.

32.  What are halophiles and where do they live?

 A: Halophiles are bacteria that live in extreme salty areas.

33.  What are thermoacidophiles and where can they be found?

A: Thermoacidophiles are bacteria that live in hot springs.

34.  What are methanogens and where do they thrive?

A: Methanogens are bacteria that live in marshy areas.

35.  How do archaebacteria differ from other bacteria?

A: Archaebacteria differ from other bacteria by having a different cell wall structure.

36.  What is the significance of the different cell wall structure in archaebacteria?

A: The different cell wall structure allows archaebacteria to survive in extreme conditions.

37.  Where are methanogens present in ruminant animals?

A: Methanogens are present in the gut of several ruminant animals such as cows and buffaloes.

38.  What role do methanogens play in the production of biogas?

A: Methanogens are responsible for the production of methane (biogas) from the dung of ruminant animals like cows and buffaloes.

39.  What characterizes eubacteria or 'true bacteria'?

A: Eubacteria are characterized by the presence of a rigid cell wall, and if they are motile, they have a flagellum.

40.  What are cyanobacteria also known as?

A: Cyanobacteria are also referred to as blue-green algae.

41.  What type of chlorophyll do cyanobacteria have, and what is their mode of nutrition?

A: Cyanobacteria have chlorophyll a similar to green plants and are photosynthetic autotrophs.

42.  What forms can cyanobacteria take?

A: Cyanobacteria can be unicellular, colonial, or filamentous.

43.  In what environments can cyanobacteria be found?

A: Cyanobacteria can be found in freshwater, marine, or terrestrial environments.

44.  What surrounds the colonies of cyanobacteria?

A: The colonies of cyanobacteria are generally surrounded by a gelatinous sheath.

45.  What phenomenon do cyanobacteria often cause in polluted water bodies?

A: Cyanobacteria often form blooms in polluted water bodies.

46.  What is the function of heterocysts in some cyanobacteria?

A: Heterocysts in some cyanobacteria fix atmospheric nitrogen.

47.  Give examples of cyanobacteria that have heterocysts.

A: Examples of cyanobacteria with heterocysts are Nostoc and Anabaena.

48.  What do chemosynthetic autotrophic bacteria oxidize for energy?

A: Chemosynthetic autotrophic bacteria oxidize various inorganic substances such as nitrates, nitrites, and ammonia.

49.  What role do chemosynthetic autotrophic bacteria play in the environment?

A: They play a great role in recycling nutrients like nitrogen, phosphorus, iron, and sulfur.

50.  What is the most abundant type of bacteria in nature?

A: Heterotrophic bacteria are the most abundant in nature.

51.  What role do heterotrophic bacteria play in the ecosystem?

A: The majority are important decomposers.

52.  How are heterotrophic bacteria helpful to humans?

A: They are helpful in making curd from milk, producing antibiotics, and fixing nitrogen in legume roots.

53.  What are some diseases caused by pathogenic bacteria?

A: Cholera, typhoid, tetanus, and citrus canker are diseases caused by different bacteria.

54.  How do bacteria primarily reproduce?

A: Bacteria primarily reproduce by fission.

55.  What do bacteria produce under unfavorable conditions?

A: Under unfavorable conditions, bacteria produce spores.

56.  How do bacteria reproduce sexually?

A: Bacteria reproduce sexually by adopting a primitive type of DNA transfer from one bacterium to another.

57.   What are Mycoplasma known for?

A: Mycoplasma are known for completely lacking a cell wall.

58.  What is unique about Mycoplasma compared to other living cells?

A: Mycoplasma are the smallest living cells known and can survive without oxygen.

59.  Are Mycoplasma pathogenic, and if so, to what organisms?

A: Many Mycoplasma are pathogenic to animals and plants.