CHAPTER 7: Diversity in Living Organisms (Date : 21-10-2022)

Question 1:

Which one of the following is not a Heterotrophic Eukaryote?

Amoeba
Paramecium
Cyanobacteria
Euglena

Correct Answer : C

Explanation

Monera kingdom includes prokaryotic organisms.
- The mode of nutrition of organisms in this group can be either by synthesising their own food (autotrophic) or getting it from the environment (heterotrophic).
- This group includes bacteria, blue-green algae or cyanobacteria, and mycoplasma.
Protista group includes many kinds of unicellular eukaryotic organisms.
- Some of these organisms use appendages, such as hair-like cilia or whip-like flagella for moving around.
- Their mode of nutrition can be autotrophic or heterotrophic.
  - Examples are unicellular algae, diatoms and protozoans (Amoeba, Paramecium, Euglena).
Hence, option C is correct.

Question 2:

Consider the following statements regarding Lichens:

Lichens are fungal species that live in permanent mutually dependent relationships with cyanobacteria.
The mutually dependent relationship exhibited by lichens is termed as parasitic.

Which of the statements given above is/are correct?

1 only
2 only
Both 1 and 2
Neither 1 nor 2

Correct Answer : A

Explanation

Some fungal species live in permanent mutually dependent relationships with blue-green algae (or cyanobacteria). Hence, statement 1 is correct.
- Such relationships are called symbiotic. Hence, statement 2 is not correct.
These symbiotic life forms are called lichens.
Lichens can be seen as the slow-growing large coloured patches on the bark of trees.

Question 3:

Consider the following statements:

All living organisms are divided into 4 major kingdoms: Monera, Protista, Plantae and Animalia.
Plants are divided into five groups: Thallophytes, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.

Which of the statements given above is/are not correct?

1 only
2 only
Both 1 and 2
Neither 1 nor 2

Correct Answer : A

Explanation

All living organisms are divided into five major kingdoms, namely Monera, Protista, Fungi, Plantae and Animalia. Hence, statement 1 is not correct.
- The classification of life forms is related to their evolution.
- Plantae and Animalia are further divided into subdivisions on the basis of increasing complexity of body organisation.
  - Plants are divided into five groups: Thallophytes, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms. Hence, statement 2 is correct.
  - Animals are divided into ten groups: Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, Protochordata and Vertebrata.

Question 4:

Consider the following statements regarding the Plant Kingdom:

Thallophytes don’t have a well-differentiated body.
Bryophyta are called the amphibians of the plant kingdom.
Angiosperms are also called flowering plants.

Which of the statements given above is/are correct?

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3

Correct Answer : D

Explanation

Plants are divided into five groups: Thallophytes, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.
- Thallophyta: Plants that do not have a well-differentiated body design fall in this group. The plants in this group are commonly called algae. These plants are predominantly aquatic. Hence, statement 1 is correct.
- Bryophyta are called the amphibians of the plant kingdom. The plant body is commonly differentiated to form stem and leaf-like structures. Hence, statement 2 is correct.
- Pteridophyta: In this group, the plant body is differentiated into roots, stem and leaves and has specialised tissue for the conduction of water and other substances from one part of the plant body to another.
- Gymnosperm term is derived from two Greek words: gymno– means naked and sperma– means seed. The plants of this group bear naked seeds and are usually perennial, evergreen and woody.
- Angiosperm word is made from two Greek words: angio means covered and sperma– means seed. These are also called flowering plants. The seeds develop inside an ovary which is modified to become a fruit. Hence, statement 3 is correct

Question 5:

Consider the following statements regarding the Vertebrates:

Cyclostomes are jawless vertebrates.
Amphibians and Aves have three-chambered heart.
Most mammals give birth to young ones whereas some mammals lay eggs.

Which of the statements given above is/are correct?

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3

Correct Answer : C

Explanation

Vertebrates are grouped into six classes:
- Cyclostomes are jawless vertebrates. They are characterised by having an elongated eel-like body, circular mouth, slimy skin and are scaleless. Hence, statement 1 is correct.
- Pisces include fish. They are exclusively aquatic animals. Their skin is covered with scales/ plates. They obtain oxygen dissolved in water by using gills. The body is streamlined, and a muscular tail is used for movement. They are cold-blooded and their hearts have only two chambers, unlike the four that humans have.
- Amphibians differ from the fish in the lack of scales, in having mucus glands in the skin, and a three-chambered heart. Respiration is through either gills or lungs. They lay eggs. These animals are found both in water and on land. E.g., Frogs.
- Reptilia are cold-blooded animals, have scales and breathe through lungs. While most of them have a three-chambered heart, crocodiles have four heart chambers. They lay eggs with tough coverings and do not need to lay their eggs in water, unlike amphibians. E.g., Snake, Crocodile.
- Aves are warm-blooded animals and have a four-chambered heart. They lay eggs. There is an outside covering of feathers, and two forelimbs are modified for flight. They breathe through lungs. All birds fall under this category. Hence, statement 2 is not correct.
- Mammals are warm-blooded animals with four-chambered hearts. They have mammary glands for the production of milk to nourish their young. Their skin has hairs as well as sweat and oil glands. E.g., Human, Rat, Cat.
  - Most mammals familiar to us produce live young ones. However, a few of them, like the platypus and the echidna lay eggs, and some, like kangaroos give birth to very poorly developed young ones. Hence, statement 3 is correct.