INTRODUCTION TO DIVERSITY IN LIVING WORLD
“We are all different, which is great because we are all unique. Without diversity, life would be very boring.”
Diversity in the living world is the first unit in the biology syllabus for NEET preparation. This unit provides a detailed study plan of amazing diversity in living organisms. From the perspective of its importance in the NEET exam, the unit diversity in the living world provides approximately 11% of questions from various chapters that are discussed further.
After reading the unit diversity in the living world, you will learn the description of various diverse living organisms from the perspective of taxonomy. It means you will have an understanding of classification, properties, attributes and exceptional features of living organisms. The concepts gained in this unit will apply in further chapters like structural organization in plants and animals and reproduction. Hence, it is essential to have a smooth comprehension of the chapters in the unit diversity in the living world. As this unit provides a great lot of examples, features and factual points, it sometimes becomes tedious to learn the concepts. Therefore, it is imperative to know about the nature of the chapters in the unit diversity in the living world and prepare yourself accordingly. Ultimately, our aim is to make sure that the maximum number of questions are answered from this unit.
Let us have an idea about the different chapters of the unit diversity in the living world.
1. The Living World: This chapter introduces the features of a living organism. You will be able to understand the metabolic uniqueness present in the living organisms. The living world also explains the hierarchy of taxonomic classification and taxonomical aids. Hence, this chapter acts as the base for the upcoming chapters of diversity in the living world.
2. Biological Classification: The essence of efforts made by scientists since the dawn of civilization will be described in the chapter biological classification. This chapter has a component of the biological history of classification which beautifully captures the mind of the students such that you will be connected to the diverse living organisms. Finally, the focus is on the five-kingdom classification scheme proposed by R.H Whittaker. There are three kingdoms covered in the chapter biological classification as:
The Kingdom Monera will take you to the tour of the world of bacteria, wherein you will read the prokaryotic organization of cells, different forms of nutrition in bacteria, their types and forms, etc. As per the requirement of NEET, you will have to read about archaebacteria as well apart from eubacteria, cyanobacteria, and mycoplasma. Also, the details of the prokaryotic cellular organization in this chapter will help you in the unit Cell Structure and Function.
The Kingdom Protista will introduce you to the eukaryotic cellular organization. You will meet chrysophytes, euglenoids, dinoflagellates, slime moulds, and protozoans in the Kingdom Protista.
The Kingdom Fungi will have you read and understand the ubiquitous fungal forms, their mode of nutrition, their types and the mode of reproduction in various forms. You will have to know about the classes of kingdom fungi on the basis of their hyphae, reproduction and fruiting bodies.
Viruses, viroids, prions, and lichens are also given a place in this chapter because these forms were not classified in any kingdom within the five-kingdom classification. Hence, the classification of viruses, the plant and animal viruses and the diseases caused by them will be discussed in the chapter biological classification.
The Kingdom Plantae and Kingdom Animalia are discussed in separate chapters.
3. Plant Kingdom: It is the fourth kingdom in the Five-Kingdom Classification scheme given by Whittaker. This kingdom allows you to understand the organisms with the autotrophic mode of nutrition along with some exceptional plants that have heterotrophic mode of nutrition. The following divisions are discussed in the chapter plant kingdom:
Thallophyta: This division talks about the algae and their various forms.
Bryophyta: This division talks about the plants that are referred to as the amphibians of the plant kingdom.
Pteridophyta: This division will have you know the first terrestrial plants that developed essential terrestrial features, importantly the vascular tissues.
Gymnosperms: This division talks about the plants that dominated the earth during the Jurassic period. They do not make flowers, hence, they produce naked seeds.
Angiosperms: This division talks about the successful plants of today's' era. These are flowering plants. However, in this chapter, there is a brief discussion of their morphology, anatomy, and reproduction because these have been discussed in details in the separate chapters.
4. Animal Kingdom: It is the fifth and the detailed kingdom in the Five-Kingdom Classification given by Whittaker. The Animal Kingdom contains some very fascinating animals. Reading this chapter would make you feel like reading a fairy tale! You will understand the organization of body form of animals, various body symmetries, coelom, notochord, etc. based on the notochord, the animal kingdom is divided into two broad categories of Invertebrata and Vertebrata. The following phyla are discussed in this chapter:
Phylum Porifera: Deals with the primitive and simple animals called Sponges.
Phylum Coelenterata: Deals with aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals.
Phylum Ctenophora: Deals with sea walnuts or comb jellies that are exclusively marine and radially symmetrical.
Phylum Platyhelminthes: Deals with flatworms that are mostly endoparasites found in animals including human beings.
Phylum Aschelminthes: Deals with roundworms that may be free-living, aquatic and terrestrial or parasitic in plants and animals.
Phylum Annelida: Deals with aquatic (marine and freshwater) or terrestrial, free-living, and sometimes parasitic animals.
Phylum Arthropoda: This is the largest phylum of the Kingdom Animalia which includes insects.
Phylum Mollusca: It is the second-largest phylum of the Kingdom Animalia. It deals with soft-bodied animals.
Phylum Echinodermata: It is considered as the advance phylum consisting of starfishes, brittle stars, etc.
Phylum Hemichordata: This phylum shows the affinities to both the invertebrates as well as vertebrates.
Phylum Chordata: This phylum shows the animals with the notochord. It is further divided into Urochordata, Cephalochordata, and Vertebrata.
Develop a thorough understanding of the basis of classification schemes proposed by various scientists.
Understand the utility of acceptance of Five-Kingdom Classification scheme proposed by R.H Whittaker along with its advantages and disadvantages.
Know the differences between the prokaryotic and eukaryotic cells and cellularity in living organisms.
Examples are very crucial in the study of diversity in the living world. Having the examples written in tabular forms of point-wise will help you in quick revision.
Refer to NCERT textbook for examples. Previous years’ questions have shown that the examples have come directly from the NCERT text.
From the analysis of previous years’ question papers, the animal kingdom becomes very important from the perspective of the number of questions.
Solve as many questions as possible. As the unit diversity in the living world gives a lot of factual information, it will be of great help that you prepare bullet notes from questions. This manner of reverse learning helps a lot with memorizing examples and facts.
The NCERT textbook for class 11
A Textbook of CBSE Biology for Class 11 by Sarita Aggarwal
Trueman’s Elementary Biology Volume 1
In bryophytes and pteridophytes, transport of male gametes requires:
A jawless fish, which laws eggs in fresh water and whose ammocoetes larvae after metamorphosis return to the ocean is :
Body having meshwork of cells, internal cavities lined with food filtering flagellated cells and indirect development are the characteristics of phylum: