NCERT Class 9 Science Important Chapter 12 Patterns in Life: Diversity and Classification English Medium As Per New Syllabus. NCERT Class 9 Science Important Chapter 12 Patterns in Life: Diversity and Classification Notes to each chapter is provided in the list so that you can easily browse throughout different chapter NCERT Class 9 Science Important Chapter 12 Patterns in Life: Diversity and Classification Question Answer Download PDF and select needs one. CBSE Class 9 Science Additional Solutions.
NCERT Class 9 Science Important Chapter 12 Patterns in Life: Diversity and Classification
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Patterns in Life: Diversity and Classification
Chapter – 12
| IMPORTANT QUESTION ANSWER |
Short Questions & Answers:
1. What is biodiversity?
Ans: Biodiversity refers to the immense variety of living organisms existing in countless forms and habitats on the Earth.
2. What are endemic species? Give one example from India.
Ans: Endemic species are species that are restricted to particular regions of the world and are not found naturally anywhere else. An example is the Lion-tailed macaque found in India.
3. What are biodiversity hotspots?
Ans: Regions that support a large number of endemic species and have undergone significant habitat loss, such as the Western Ghats and the Himalayas, are known as biodiversity hotspots.
4. Why is biological classification necessary?
Ans: Classification helps organise the vast diversity of life systematically, making it easier to study organisms, understand their relationships, and identify newly discovered species.
5. Who proposed the Five Kingdom classification system in 1969?
Ans: Robert H. Whittaker proposed the Five Kingdom classification system in 1969.
6. What are the five kingdoms in Whittaker’s classification?
Ans: The five kingdoms are Monera, Protista, Fungi, Plantae, and Animalia.
7. What are the key characteristics of organisms in Kingdom Monera?
Ans: Organisms in Kingdom Monera, such as bacteria and cyanobacteria, are single-celled prokaryotes, meaning they do not possess a true, membrane-bound nucleus.
8. To which kingdom do unicellular eukaryotes like Amoeba and Paramecium belong?
Ans: They belong to Kingdom Protista, which consists of single-celled eukaryotic organisms.
9. What is the cell wall of fungi made of?
Ans: The cell wall of fungi is primarily made up of chitin.
10. What is a symbiotic relationship in lichens?
Ans: Lichens are a mutualistic association between an autotrophic alga (which photosynthesises and provides food) and a heterotrophic fungus (which provides protection).
11. Why are Bryophytes referred to as the “amphibians” of the plant kingdom?
Ans: Bryophytes, such as mosses, are called amphibians of the plant kingdom because, although they live on land, they strictly require water to reproduce.
12. Which plant group is the first to develop a specialised structural transport system?
Ans: Pteridophytes (like ferns) are the first to possess true roots, stems, leaves, and specialised vascular tissues (xylem and phloem) for transporting water and food.
13. What is the primary difference between gymnosperms and angiosperms?
Ans: Gymnosperms produce naked seeds that are not enclosed in fruits (often exposed on cones), whereas angiosperms produce seeds that are safely enclosed within fruits.
14. What structural feature separates chordates from non-chordates (invertebrates)?
Ans: The presence or absence of a notochord, a flexible rod-shaped structure, is the major criterion separating chordates from invertebrates.
15. How do organisms in Phylum Porifera (sponges) obtain food and oxygen?
Ans: Sponges have numerous pores in their bodies that allow water to continuously flow through, bringing food particles and oxygen directly to their cells.
16. What evolutionary advantage does segmentation provide to Annelids like earthworms?
Ans: Segmentation provides the body with greater flexibility and allows for more precise control of movements.
17. Which phylum contains animals with jointed appendages and a hard external skeleton?
Ans: Phylum Arthropoda, which includes insects, spiders, and crabs, is characterised by jointed appendages and a hard external skeleton (exoskeleton).
18. What is binomial nomenclature?
Ans: Binomial nomenclature is a universal system introduced by Carolus Linnaeus for naming organisms using a two-part scientific name consisting of the genus and the species.
19. What are the key rules for writing a scientific name?
Ans: The genus name must come first and start with a capital letter, followed by the species name in small letters. Both names must be written in italics when printed or underlined when handwritten.
20. What are the three domains of life proposed by Carl Woese?
Ans: Based on genetic data, Carl Woese proposed a three-domain system dividing life into Bacteria, Archaea, and Eukarya.
Fill in the Blanks:
1. Robert H. Whittaker proposed the __________ Kingdom classification system.
Ans: Five.
2. The cell wall of fungi is mainly made of __________.
Ans: Chitin.
3. The scientific naming system using two names is called __________ nomenclature.
Ans: Binomial.
4. Bryophytes are known as the __________ of the plant kingdom.
Ans: Amphibians.
5. The three-domain system of classification was proposed by __________ Woese.
Ans: Carl.
True or False:
1. Amoeba belongs to Kingdom Protista.
Ans: True.
2. Gymnosperms produce seeds enclosed within fruits.
Ans: False.
3. Arthropods have jointed appendages and an exoskeleton.
Ans: True.
4. Endemic species are naturally found all over the world.
Ans: False.
5. The genus name in a scientific name begins with a capital letter.
Ans: True.
Long Questions & Answers:
1. Describe the various criteria used by scientists to classify living organisms and explain how the classification systems have evolved from Aristotle’s time to Whittaker’s Five Kingdom system.
Ans: To systematically organise the Earth’s vast biodiversity, scientists classify organisms based on several fundamental criteria, including cell type (prokaryotic or eukaryotic), cellular organisation (unicellular or multicellular), the presence or absence of a cell wall, mode of nutrition (autotrophic or heterotrophic), and internal body structures. Historically, classification systems have continuously evolved alongside scientific advancements; for example, Aristotle initially grouped animals simply by their habitat (land, water, and air). In the 18th century, Carolus Linnaeus introduced the Two Kingdom system (Plantae and Animalia), but this created confusion for microscopic organisms like Amoeba and bacteria. As microscopes improved, scientists added Protista for unicellular eukaryotes with a true nucleus, and later Monera for prokaryotic bacteria that lacked a true membrane-bound nucleus. Finally, Robert H. Whittaker proposed the comprehensive Five Kingdom classification in 1969 by placing Fungi into a separate kingdom, recognising that they are multicellular, heterotrophic eukaryotes with a chitin cell wall that absorb nutrients from dead and decaying matter.
2. Explain the evolutionary progression of plants within the Kingdom Plantae, detailing how the five major classes adapted to survive on land.
Ans: The Kingdom Plantae is divided into five classes—Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms—which beautifully demonstrate a sequence of structural adaptations from aquatic life to complex terrestrial survival. Thallophytes (algae like Spirogyra) have a simple, undifferentiated body called a thallus and are primarily restricted to aquatic environments. Bryophytes (like mosses), known as the amphibians of the plant kingdom, took the first steps onto land by developing root-like rhizoids, but they still strictly require moist environments to reproduce. Pteridophytes (like ferns) evolved further by developing true roots, stems, leaves, and specialised vascular tissues (xylem and phloem) for transporting water and food, though they still lack seeds and need aquatic conditions for reproduction. Gymnosperms (like pines) overcame the need for water in fertilisation and developed needle-like leaves to prevent water loss, reproducing via naked seeds often exposed on cones. Finally, Angiosperms became the most advanced and diverse plant group by producing flowers to attract pollinators for highly efficient reproduction and enclosing their seeds safely within fruits to aid in widespread dispersal.
3. How is the Kingdom Animalia broadly classified based on the presence of a notochord, and what major evolutionary advancements are seen across the different invertebrate phyla?
Ans: Kingdom Animalia is primarily divided into two broad groups—non-chordates (invertebrates) and chordates—based on the absence or presence of a notochord, which is a flexible rod-shaped internal support structure. Within the invertebrates, there is a clear evolutionary progression in body complexity: Porifera (sponges) exhibit the simplest multicellular plan with a porous body lacking true tissues, while Cnidaria (like jellyfish) introduce tissue-level organisation and tentacles for active feeding. Platyhelminthes (flatworms) bring further advancement with bilateral symmetry and a distinct head-tail region for directional movement, which then evolves in Nematoda (roundworms) into a cylindrical body with a complete digestive system featuring two openings. Annelids (earthworms) introduce body segmentation and a true body cavity for greater flexibility, whereas Arthropods (insects and crabs) develop jointed appendages and a hard exoskeleton to survive in dry environments. Finally, Molluscs (snails) feature soft bodies often protected by a shell, and Echinoderms (starfish) show a significant shift towards internal support by developing a hard internal skeleton made of calcium carbonate, bridging the structural gap towards higher animals.
4. What is binomial nomenclature, who introduced it, and why is it essential alongside the hierarchical nature of biological classification?
Ans: Binomial nomenclature is a universal scientific system of naming living organisms introduced by Carolus Linnaeus in the 18th century, designed to eliminate the confusion caused by an organism having multiple different common names across various languages and regions. Under this system, every organism is given a unique two-part scientific name written in Latin; the first part is the Genus (which begins with a capital letter) and the second is the species (written entirely in lowercase), and the name is always italicised in print or underlined when handwritten, such as Panthera tigris for the tiger. This naming system is a crucial component of the broader hierarchical classification, which arranges life step-by-step from vast, inclusive categories down to highly specific ones in the order of Kingdom, Phylum, Class, Order, Family, Genus, and Species. Just like a detailed postal address helps locate a specific house, this hierarchical system and standard naming convention allow scientists worldwide to accurately identify organisms, systematically study their shared features, and deeply understand their evolutionary relationships.
5. Define biodiversity and biodiversity hotspots, providing examples from India, and explain why conserving these ecosystems is crucial.
Ans: Biodiversity refers to the immense variety of life forms, ranging from microscopic organisms to giant trees and diverse animals, along with the countless habitats they occupy across the Earth. Certain regions that support a massive number of endemic species—organisms that are strictly restricted to that specific area and found nowhere else in the world, such as India’s Lion-tailed macaque, Nilgiri tahr, and Nepenthes khasiana—and which have simultaneously suffered significant habitat loss, are designated as biodiversity hotspots. India is home to several major global biodiversity hotspots, including the Western Ghats, the Himalayas, and Indo-Burma. Conserving these rich hotspots is absolutely vital for global stability because every organism plays a crucial role in maintaining interconnected food webs; for instance, microscopic algae produce the oxygen we breathe, fungi recycle waste into fertile soil, and animals pollinate crops. If human activities like deforestation, pollution, and climate change cause even a single species to go extinct, it can trigger a domino effect, leading to the decline of other dependent species and threatening the overall ecological balance, food security, and human livelihoods.
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