Zoology- Definition, Branches and Importance of Zoology

Zoology Definition

Zoology is the study of biology that deals with the different aspects of animals. This is a vast discipline that learns about the interaction between organisms and their environments, classification, physiology, behaviour, and evolution. The zoologists trace the mystery in nature by studying the various lives of animals, which helps our understanding of the balance in nature that sustains ecosystems.

Zoology continued to advance with the Age of Evolution in the 17th and 16th centuries, as scientific research offered improved ways of categorisation. Animals of the kingdom Animalia were categorised into a five-kingdom system, further grouped into phyla, classes, orders, families, genera, and species.

Branches of Zoology

Zoology includes many sub-disciplines, each dealing with particular aspects of animal life. Some of the main branches of zoology include:

Classification of the Animal Kingdom

There are different species in the animal kingdom, each with certain unique characteristics and adaptations. The classification system followed in zoology works to systematically organise and understand how these various animals relate to one another. Major groups within the animal kingdom include:

• Vertebrates Groups: Those animals that have a backbone, such as mammals, birds, reptiles, amphibians, and fishes.

• Invertebrates: Those that do not have a backbone, including insects, molluscs, and worms.

Characteristics of Animals

Animals have certain distinctive features which can help distinguish them from other life forms. These are listed as under:

• Multicellular Structure: Animals possess more than one cell, which co-operatively perform many functions

• Heterotrophic Nutrition: They cannot produce their food and rely on other living sources for deriving energy

• Mobility: Most animals can have locomotion skills at some stages of their lives.

• Nervous System: Most animals have a developed nervous system to process information and respond to the environment.

• Sensory Organs: Well-developed sense organs make it possible for an animal to perceive the surroundings in which it may be living.

Examples of the Animal Kingdom

The animal kingdom consists of a large number of species. Each animal is specially adapted to certain conditions that constitute the environment of an individual. Grouping into different categories makes identification and studies easier. These are grouped into the following examples:

Class 12 Zoology Chapters for NEET 2027

Given below is the list of important Zoology chapters of class 12 syllabus for NEET Exam preparation:

Best Zoology Books for the NEET Exam

The best Zoology books for NEET preparation are:

• NCERT textbook Biology Class 11

• NCERT textbook Biology Class 12

• Trueman's Objective Biology

• Dinesh Objective Biology

• Biology by Campbell and Reece

• MTG's NCERT at Your Fingertips

These books provide a strong foundation and practice material for mastering Zoology for NEET.

Some NEET Zoology MCQs

Question: Which of the following is a type of fluid connective tissue?

1. Blood

2. Lymph

3. Both a and b

4. None of the above

Correct answer: 3) Both a and b

Explanation:

Fluid connective tissue includes blood and lymph, both of which play essential roles in transportation and immunity. Blood consists of plasma, red blood cells (RBCs) for oxygen transport, white blood cells (WBCs) for immune defence, and platelets for clotting. It circulates nutrients, gases, hormones, and waste throughout the body. Lymph, derived from interstitial fluid, contains WBCs, particularly lymphocytes, and is crucial for immune responses, maintaining fluid balance, and transporting fats from the digestive system. Both blood and lymph serve as vital fluid connective tissues that help maintain homeostasis in the body.

Hence, the correct answer is option 3) Both a and b

Question: There is no DNA in:

1. Mature RBCs

2. Mature spermatozoan

3. Hair Root

4. An enucleated ovum

Correct answer: 1) Mature RBCs

Explanation:

RBCs are formed in the red bone marrow in adults. RBCs lack nuclei in most mammals and are biconcave in shape.

They have a red-coloured, iron-containing complex protein called haemoglobin, hence the colour and name of these cells. A healthy individual has 12-16 gms of haemoglobin in every 100 ml of blood.

Mature RBCs are devoid of a nucleus, and DNA is absent.

Question: Menstrual bleeding is the result of

1. Low levels of ovarian hormones

2. High level of ovarian hormones

3. High levels of LH

4. High levels of FSH

Correct Answer: 1) Low levels of ovarian hormones

Ovarian hormones like progesterone and estrogen contribute to low levels, which trigger menstrual bleeding. These hormones support the health of the endometrium; if their levels reduce, the process of shedding occurs, and a woman experiences menses. That is part of the menstrual cycle, which includes the regulation through several hormones of the pituitary gland, such as luteinizing hormone and follicle-stimulating hormone. Menstrual bleeding is usually for 4 to 8 days and is part of the normal features of the menstrual cycle.

Hence, the correct answer is option 1) Low levels of ovarian hormones

Question: Assertion (A): Integration into the host cell's chromosome is a common outcome for plasmids used as cloning vectors following transformation.

Reason (R): Plasmids undergo fragmentation or disintegration upon transformation.

1. Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).

2. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

3. Assertion (A) is true, but Reason (R) is false.

4. Both Assertion (A) and Reason (R) are false.

Correct answer: 4) Both Assertion (A) and Reason (R) are false.

Explanation:

Assertion (A) claims that plasmids as cloning vectors usually integrate into the host cell's chromosome after transformation. However, this statement is not true. Plasmids used as cloning vectors typically remain as separate, extrachromosomal entities within the host cell and do not integrate into the chromosome unless specific mechanisms or techniques are employed to facilitate integration.

However, Reason (R) is false in suggesting that plasmids are disintegrated after transformation. Plasmids typically do not disintegrate or fragment upon transformation. Instead, they persist as separate, extrachromosomal elements within the host cell, unless they undergo integration into the chromosome.

Hence, the correct answer is option 4) Both Assertion (A) and Reason (R) are false.