Science brings unique facts. It talks about living organisms in our surroundings. However, it also has complex concepts and theories. Therefore, it requires a deep understanding to grasp the concepts. Class 9 plays a vital role as it introduces students to many concepts in Science and it also opens many doors of opportunities for them.
Class 9 Science Chapter 7: Diversity in Living begins with introducing the living organisms and their importance. It will give students a brief of life forms and the hierarchical classification and evolution. Students will learn different topics such as Animalia, Porifera, Coelenterata, Platyhelminthes, and Nematoda.
NCERT Solutions Class 9 Science Chapter 7 question answers are available on our Extramarks website or app. The solutions help the students to clarify their doubts. The MCQs, long answers, short answers and tips and tricks will guide students to build a conceptual command of the topics present in the chapter. With the help of NCERT Solutions Class 9 Science Chapter 7, students can score well in the examinations.
Extramarks is the most trusted online learning platform; lakhs of students pursuing secondary education refer to our NCERT Solutions. Students who face difficulty answering the questions can refer to NCERT Solutions Class 9 Science Chapter 7. The solutions are very beneficial from the examination perspective.
Students can regularly visit our Extramarks website for the latest updates and exam-related news. In addition, they can also refer to NCERT solutions class 10, NCERT Solutions class 11 and NCERT solutions class 12.
Key Topics Covered In NCERT Solutions Class 9 Science Chapter 7:
NCERT Solutions Class 9 Science Chapter 7 introduces students to accurate answers to the end-text NCERT questions. As the explanations are comprehensive, the fundamentals of the chapter are understood by the students in a better way.
. They will learn about organisms of various shapes and sizes. In addition, they will understand why there is a need for a system of classification because of the vast diversity of living beings. Finally, students will learn about the classification of Aristotle and its drawbacks.
Some of the key topics featured in NCERT Solutions Class 9 Science Chapter 7 are:
|7.1||Basis of Classification|
|7.2||Classification and Evolution|
|7.3||The Hierarchy of Classification Groups|
|7.4||Classification of Plantae|
|7.5||Classification of Animalia|
7.1 Basis of Classification
There are many organisms living on this planet. Over a million species are found in the largest Phylum, the animal kingdom. Many species of plants are available, from tiny grasses to large Eucalyptus trees.
Because of the diversity of living creatures, there is a need to have a system for classification. However, it is difficult to study each one individually. Therefore, animals and plants were divided into groups and subgroups to facilitate their study. The classification system was thus born.
The basis of classification explained in NCERT Solutions Class 9 Science Chapter 7 are:
- Presence or Absence of Nucleus in Cells
- Prokaryotes are organisms that have cells with no well-defined nucleus.
- Eukaryotes are organisms that have well-defined nuclei. Therefore, cells that have a nucleus and membrane-bound organelles are more efficient.
- Number of Cells in an Organism
- Unicellular: Organisms with only one cell are called unicellular. They are responsible for all functions that are necessary to sustain life.
- Multicellular: Organisms with more than one cell are known as multicellular. Multicellular organisms can have more cells, which allows for more efficiency.
- Mode of nutrition
- Autotrophs are organisms that produce their own food. For example, all green plants are considered autotrophs. This is because the green parts of the plants have a pigment called chlorophyll that facilitates photosynthesis.
- Heterotrophs are organisms that depend on plants or animals. They don't have any chlorophylls. Further, this group includes all animals, fungi, certain bacteria and protozoa.
7.2 Classification and Evolution
- Most of today's living creatures are a result of body modifications that allow them to live longer.
- There is a possibility that design complexity will increase over time. It's not unreasonable for older organisms to be simpler than younger ones. Therefore, there is a need to classify the microorganism and segregate them in a particular hierarchy.
7.3 The hierarchy of classification groups
Ernst Haeckel (1894), Robert Whittaker (1969 ), and Carl Woese (1977) were some of the biologists who attempted to group all living organisms into broad categories called kingdoms.
We can separate organisms based on a hierarchy of characteristics into smaller groups. This is how we get to the fundamental unit of classification, which, in turn, is a "species". A species is any organism that is similar enough to reproduce and breed.
- These organisms don't have a nucleus or organelles and are unicellular.
- Some organisms in this group have cell walls.
- Nutrition: Heterotrophic or autotrophic
- Examples: Bacteria, blue-green algae
- Unicellular eukaryotic organisms.
- Locomotion: A hair-like cilia, or whip-like flagella that allows members to move around in their way.
- Nutrition: Heterotrophic or autotrophic.
- Examples: Algae, protozoans
- Heterotrophic eukaryotic organisms
- Nutrition: Some of them eat decaying organic material as their food and are called as saprotrophs.
- Multicellular eukaryotes have cell walls.
- Nutrition: They are autotrophs as they do photosynthesis by chlorophyll.
- Multicellular eukaryotes without cell walls
- Nutrition: Heterotrophic
Classification of plants explained in NCERT Solutions Class 9 Science Chapter 7 are:
Thallophyta and Algae: These plants do not have a well-differentiated body structure. These plants are often called algae. These plants are mainly aquatic. These plants include Spirogyra, Ulothrix and Cladophora.
Bryophyta is the amphibian in the plant kingdom. Commonly, the plant body can be divided to create stem- and leaf-like structures. However, no specialised tissue can conduct water or other substances from one area of the plant's body to the other. Marchantia and Funaria are two examples.
Pteridophyta is a plant body that can be divided into roots, stems and leaves. It also has specialised tissue to conduct water from one area of the plant body. Marsilea and ferns are some examples.
Angiosperm combines two Greek words: angio, which means "covered", and sperm, which means "seed". The seeds are created inside an organ that is transformed into a fruit. These are also known as flowering plants. The structures of plant embryos in seeds are called cotyledons.
Students can refer to NCERT Solutions for Class 9 Science Chapter 7 to get detailed answers of the end-text questions of this chapter which enables them to understand the plant kingdom.
The classification of animal kingdom explained in NCERT Solutions Class 9 Science Chapter 7 are:
- These animals are attached to a solid support that contains spicules made of silica, calcium carbonate, or other non-motile substances.
- They have "pores", or holes, all over the body. These lead to a canal system, which helps to circulate water throughout the body to bring in oxygen and food.
- Aquatic animals
- The body has a cavity. Two layers of cells make up the body.
- Jellyfish and sea anemones are common examples.
- The body is bilaterally symmetrical. This means that both the left and right halves have the same design.
- Differentiated tissues can be made from three layers of cells, therefore such animals are called triploblastic.
- The body is bilaterally symmetrical and triploblastic.
- The body is more cylindrical than flattened.
- A false body cavity or pseudocoelom is present.
These animals have an internal skeleton and an actual vertebral column, which allows a completely different distribution of muscle attachment points. In addition, vertebrates have complex differentiation of organs and tissues and are bi-symmetrical, triploblastic and coelomic. These features are found in all chordates, as described in Extramarks NCERT Solutions Class 9 Science Chapter 7.
- Have notochord
- Have dorsal nerve cord
- Are triploblastic
- Have paired gill pouches
- Are coelomate
NCERT Solutions Class 9 Science Chapter 7: Exercise & Answer
NCERT Solutions Class 9 Science Chapter 7 talks about the classification and evolution of various plants and animal kingdoms. Students preparing for their annual exams can refer to our NCERT Solutions. The solutions are made while keeping the exam pattern and CBSE guidelines in mind.
Students can start with a trial account by registering on our website. Class 9 Science chapter 7 offers detailed answers to various questions, including match the pair, true or false, and descriptive questions. It helps students to get a better understanding of the concepts and improve their exam preparation.
Click on the links below to the exercise specific questions and their solutions which are covered in NCERT Solutions Class 9 Science Chapter 7:
- Chapter 7: Exercise 7.1 Solutions: 3 Questions
- Chapter 7: Exercise 7.2 Solutions: 2 Questions
- Chapter 7: Exercise 7.3 Solutions: 3 Questions
- Chapter 7: Exercise 7.4 Solutions: 3 Questions
- Chapter 7: Exercise 7.5 Solutions: 4 Questions
- Chapter 7: Exercise 7.6 Solutions: 1 Questions
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NCERT Exemplar for Class 9 Science:
Science can be a challenging subject as it has complex concepts and theories. Solving different types of questions with a higher difficulty level will be helpful. It enhances students' understanding of essential topics and increases problem-solving skills.
NCERT Exemplar for Class 9 science introduces essential questions from the Science subject of Class 9. It is prepared by Extramarks subject-matter experts who have systematically arranged the questions. During the preparation for the exam, having an NCERT Exemplar will help them score good marks. It has different types of questions which include descriptive and multiple-choice..
Our NCERT Solutions Class 9 Science Chapter 7 has questions from the NCERT Exemplar. Students get questions with proper arrangement and organised manner. Each topic consists of various questions and answers with illustrations for better understanding.
Key Features of NCERT Solutions Class 9 Science Chapter 7:
NCERT Solutions play a vital role in preparing for exams and entrance tests. Extramarks have a team of experts in Science who provide appropriate solutions for every type of question. As a result, students will be able to comprehend the topics in Class 9, Chapter 7.
Some of the critical features of NCERT Solutions Class 9 Science Chapter 7:
- It helps the students clarify all their doubts about the diversity in living organisms.
- The NCERT solution is a reference guide containing the answers to the questions given in the textbook exercise.
- The solutions give a clear understanding of the chapter's concepts so that students can understand them before appearing for the exam.
- Students will be able to study the solutions again if required.
- NCERT Solutions Class 9 Science Chapter 7 also provides information about past years' questions and current year questions with answers.
- It can also be used for competitive exams like NTSE, ICSE, IIT-JEE and other entrance exams.
- NCERT Solutions Class 9 Science Chapter 7 assists the students in understanding the topics and also building a solid conceptual base through well explained answers.
Q.1 What are the advantages of classifying organisms?
Following are the advantages of classifying organisms:
- Classifying organisms helps us in recognising and establishing the basic arrangement of a hierarchical structure among diverse species.
- It helps us in establishing relationship and resemblances between various organisms and thus facilitates research of wide variety related with organisms.
- It helps in understanding the evolution of organisms, as it gives us the information,allowing a reconstruction of phylogeny of life.
Q.2 How would you choose between two characteristics to be used for developing a hierarchy in classification?
We should choose the basic characteristics among several other characteristics for developing a hierarchy of classification. The basic characteristics that are chosen are free of any other characteristics in their effects on the form and function of the organism. The characteristics in the next level would be dependent on the previous one and would help in deciding the variety in the next level. In this way, the entire hierarchy of commonly related characteristics would be build to be used for classification. This helps in the establishment of hierarchy of characteristics.
Q.3 Explain the basis for grouping organisms into five kingdoms.
In 1959, Robert H Whittaker proposed a five kingdom classification of living organisms on the basis of cell structure, mode and source of nutrition and body organisation as main features. The five kingdoms proposed by Whittaker are Monera, Protista, Fungi, Plantae and Animalia.
The basis for grouping organisms into five kingdoms:
- Complexity of cell structure- based on the presence of membrane bound cell organelles and well-defined nucleus the cells are broadly categorised into: prokaryotic and eukaryotic.
- Cell structure: Presence or absence of cell wall is another important characteristic
- Unicellular and multicellular organisms: Based on the number of cells present in the body of the organisms, they are categorised into unicellular and multicellular
- Mode of nutrition: Organisms basically have two types of modes of nutrition autotrophic and heterotrophic and they are classified according to that.
- Phylogenetic relationship: Phylogeny is the evolutionary history or ancestry of an organism. It is a belief that simple organisms are primitive and complex organisms are advanced. It is also believed that the advanced organisms are evolved from primitive ones. Thus, primitive and advance nature of organisms also helps in the classification of organisms into broad groups.
Q.4 What are the major divisions in Plantae? What is the basis for these divisions?
The kingdom Plantae is divided into five main divisions: Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms.
The classification depends on the following criteria:
- Differentiated or undifferentiated plant body
- Presence or absence of vascular tissues
- With or without seeds
- Naked seeds or seeds inside fruits
- The first level of classification depends on whether a plant body well differentiated or not. The plants that do not have a well differentiated body are grouped as thallophyta.
- On the basis of the presence or absence of vascular tissues, plants are catogorised as bryophytes (plants without vascular tissues) and tracheophytes (plants with vascular tissues).
- On the basis of the absence/presence of seed formation, tracheophyta is sub-divided into two divisions pteridophyta and phenerogams.
- Pteridophytes do not produce seeds.
- Phanerogams have well developed reproductive organs that produce seeds.
- On the basis of the presence of naked seeds and seeds enclosed in fruits, phanerogams are further sub-divided gymnosperms and angiosperms respectively.
- Gymnosperms are the seed bearing non-flowering plants, whereas angiosperms are flowering plants in which the seeds are enclosed within the fruit.
Q.5 How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?
Criteria for deciding divisions in plants are:
- Differentiated or undifferentiated plant body
- Presence/ absence of vascular tissues
- With or without seeds
- Naked seeds/seeds inside fruits
Criteria for deciding sub-groups in animals are:
Kingdom Animalia is divided into two major groups on the basis of the presence or absence of a notochord.
Non-chordates do not possess a notochord, while all members of a phylum chrodates possess a notochord.
Non-chordate is further divided into subgroups on the basis of the following features.
- Presence or absence of tissues
- Type of body symmetry (Radial, Bilateral)
- Types of coelom (Acoelom, Pseudocoelom, eucoelom)
- Types of true coelom (Enterocoelom and Schizocoelom)
- Presence of number of germ layers during embryonic development (Diploblastic and Triploblastic)
On the basis of the above features, non-chordates are divided into the following sub-grpups.
Porifera, Coelentrata, Platyhelminthes, Nmatodes, Annilides, Molluscs, Arthropoda and Echinodermata
All members of the phylum chordate possess a non-chordate. However, some animals such as Balanoglossus, Amphioxus, Herdmanina, etc have a notochord which is either absent or does not run the entire length of the animal’s body. Therefore, these animals are kept in a separate subphylum called Protochordata.
The rest of the chordates are included in the subphylum vertebrata. The members of the sub-phylum vertebrata are advanced chordates. They are further categorised into five classes, Pisces, Amphibia, Reptilia, Aves and Mammalia.
Q.6 Explain how animals in vertebrata are classified into further Subgroups?
All the vertebrates are bilaterally symmetrical, triploblastic, coelomic, and segmented with complex differentiation of body tissues. Following features are common to all chordates:
- dorsal nerve cord
- paired gill-pouches
Vertebrates are grouped into following five classes:
FAQs (Frequently Asked Questions)
Students can start practising with the solutions provided and understand their explanations. It is essential to evaluate the answers to different types of questions. In addition, students can also refer to other study materials available on the website.
The concepts in the Class 9 Chapter 7 are complex and challenging to understand. To perform better in the examination, students can refer to NCERT Solutions Class 9 Science Chapter 7. The solutions cover all solved questions, including filling in the blanks and matching the pair and true or false. It consists of a pictorial presentation and summarised answers.
There are many living organisms living on the planet. They come in all shapes and sizes. The kingdom Animalia and Plantae are divided into various classes and orders. This simplifies the process of understanding their history. This gives us insight into their origins and how they work.