Chapter 1 Life And Its Diversity Very Short Type Questions And Answers
Question 1. What is the life span of tortoise?
Answer: About 200 years.
Question 2. What is the function of pneumatic bones in birds?
Answer: To reduce the body weight for flying.
Question 3. Define genetic drift.
Answer: The random changes in the allele frequency which is caused by chnce above.
Question 4. How many types of biodiversity are there?
Answer:
(1) Geneticdiversity
(2) species diversity
(3) Community and Ecosystem diversity.
West Bengal Board Class 9 Life Science
Question 5. Who first proposed the term biology?
Answer: Lamarek and Treviranus in 1801
Question 6. Who is the “Father of Biology”?
Answer: Aristotle
Question 7. Who is the “Father of Botany”?
Answer: Theophrastus
Question 8. Who is the “Father of Medicine”?
Answer: Hippocrates
Question 9. What is the basic material of life?
Answer: Protoplasm.
Question 10. What is cybernetics?
Answer: The branch of science has been formed in Collaboration of biology with technology.
Question 11. What is palaentology?
Answer: Study of fossils.
Question 12. What is biogeography?
Answer: Branch of science that deals with the global distribution of plants and animals.
Question 13. What is space biology?
Answer: The study of survival problems of living things in outer space.
Question 14. Bacteria beiongs to which kingdom ?
Answer: Bacteria belongs to kingdom prokaryotae.
Question 15. Who proposed five kingdom classification of plants ?
Answer: R. Whittaker in 1969 proposed the five kingdom classification.
Question 16. Name one protista.
Answer: One Protista is Paramaecium.
Question 17. Who proposed binomial nomenclature ?
Answer: In the year 1753, the Swedish biologist Carolus Linnaeus formulated the method of Binomial (bi, two; nomen, name) nomenclature.
Question 18. Which type of leaf venations is noted in monocotyledonous plants ?
Answer: Leaves are provided with parallel venation.
Exception-Arum.
Question 19. Unicellular, eukaryotic and autotrophic plants are included in which kingdom ?
Answer: They are included in Protista.
Question 20. Name the lowest unit of taxonomy.
Answer: The lowest unit of taxonomy is species.
Question 21. Mention two groups under Thallophyta.
Answer: Plants under Thallophyta are again divided into two groups, e.g. — Algae and Fungi.
West Bengal Board Class 9 Life Science
Question 22. What is the name of body cavity in sponges ?
Answer: The body cavity in sponges is called spongocoel.
Question 23. Which cell helps in canal system of sponges ?
Answer: The canal system is helped by Choanocytes / Collar cell / flagellate cell.
Question 24. In which group of animals gastrovascular cavity is found ?
Answer: It is found in group Cnidaria.
Question 25. Which group of animals are commonly called ‘sea walnut’ ?
Answer: Ctenophores are commonly known as ‘sea walnut’.
Question 26. What is the function of nephridia in earthworm ?
Answer: Nephridia is the excretory organ of earthworm.
Question 27. Name a bird that can not fly.
Answer: Penguin is a bird of Antarctica, which can not fly.
Question 28. Name the mammal that lays eggs.
Answer: Platypus is a mammal that lays eggs.
Chapter 1 Life And Its Diversity Short Type Questions And Answers
Question 1. What is life?
Answer:
Life
Life is defined as the external manifestation of the action and interaction between the living organism and its environment. :
Question 2. What are five basic mechanism which causes Variation?
Answer: Mutation, Recombination, Gene migration, genetic drift and natural selection.
Question 3. What is divergent evolution?
Answer:
Divergent evolution
Formation of different strueture from a common ancestral form is called divergent evolution.
Question 4. What is convergent evolution ?
Answer:
Convergent evolution
Formation of similar characters among the unrelated group of organism is regarded as convergent evolution.
Question 5. What is the role of gene flow or gene migration in evolution?
Answer: Genetic variation like gene flow is the pre-requisite of evolution. Then the naturalSelection act on this genetic variation.
West Bengal Board Class 9 Life Science
Question 6. What is speciation?
Answer:
Speciation
The process by which one or more species are formed from an existing specis is called speciation.
Question 7. What is organic evolution?
Answer:
OOrganic evolution
The gradual process of change of one form of life into another and development of new type of living organism from pre-existing type over a long period of time.
Question 8. What is Eugenics?
Answer:
Eugenics
Branch of science which deals with the improvement of human race genetically by Selective control of reproduction.
Question 9. What is chemical evolution?
Answer:
Chemical evolution
The process of development of complex organic molecule such as protein, Nueleic acid from simple inorganic molecule like methane, ammonia, hydrogen etc is called chemical evolution.
Question 10. Name the following branches of biology :
(a) Application of biological processes in technology
(b) Seience of growing fruits and vegetables
(c) Study of pre-historic form of life
(d) Study of causes of immunity
(e) Study of fishes.
Answer: (a) Biotechnology
(b) Horticulture
(c) Palaentology
(d) Immunology
(e) Pisciculture
Question 11. Define taxonomy.
Answer:
Taxonomy
Taxonomy is defined as the science dealing with identification, nomenclature and classification of organism. The term taxonomy was coined by De Condolle in 1813. Carolus Linnaeus is considered as the father of taxonomy.
Question 12. What are coacervates ?
Answer:
Coacervates
According to scientists, the first sign of life was noticed in some larger organic molecules. Oparin (1924) first suggested such a structure and named it coacervate. It is a minute (1 — 100 in diameter), spherical, bubble-like structure composed of a thin layer of organic molecules rich in lipids.
Question 13. What is Immunology ?
Answer:
Immunology :
It involves the study of the defense system in animals and the mechanism by which it is achieved.
West Bengal Board Class 9 Life Science
Question 14. What is biostatistics ?
Answer:
Biostatistics :
The application of statistics in solving biological problems is called Biostatistics. :
Question 15. What are Hemichordates ?
Answer:
Hemichordates
Hemichordates are a small group of marine animals having gill slits, a structure sometimes regarded as notochord in the anterior region only and mostly solid nerve cord. Examples of hemichordates are—Balanoglossus sp. Saccoglossus sp. etc.
Question 16. Write two characteristic feature of amphibia.
Answer:
Class—Amphibia :
Characters: 1. Adults are terrestrial and lung—breathing, while larvae are aquatic and gill-breathing.
2. Skin is moist, glandular and naked (i.e., not provided with any exoskeleton).
Question 17. Write any two examples, each of phylum Mollusca and Phylum Echinodermata.
Answer:
Phylum — Mollusca :
Example: Garden snail, Octopus (Octopus vulgaris)
Phylum — Echinodermata :
Example: Sea cucumber, Starfish (Asterias rubens)
Question 18. Which group of animals are diploblastic and why ?
Answer:
Diploblastic :
When the cells are arranged in two embryonic layers, the animal is called a diploblastic animal. The two layers are ectoderm and endoderm.
Example : CnidariAnswer:
Question 19. Write two distinctive features of phylum Porifera.
Answer:
Phylum—Porifera :
(1) Body is multicellular, without well developed tissue system. Exoskeleton is hard and rigid, made up of calcium or silicon-rich cells, called spongin fibres or spicules.
(2) One large aperture, called osculum is present at the upper end of the body. There are numerous tiny pores, called ostia, spread all over their body.
West Bengal Board Class 9 Life Science
Question 20. Mention two characters of phylum Anthropoda.
Answer:
Characters :
(1) Presence of externally jointed appendages is the reason for name arthropoda.
(2) Arthropoda is the largest phylum of kingdom Animalia and over two thirds of all known species on the earth are arthropods.
Question 21. How is porifera different to other animals ?
Answer: Prorifera is multicellular like other animals but porifera does not form any tissue hence all the cells are almost independent and living together like a colony of cells. In other multicellular animals, number of cells together form a tissue having specific structure and function.
Question 22. “All vertebrates are chordates but all chordates are not vertebrates” —justifies the statement.
Answer:
“All vertebrates are chordates but all chordates are not vertebrates”
In all vertebrates, chordate features are present in early embryonic life. Thus, there is notochord which is gradually replaced by vertebral column in course of development. They have pharyngeal gill slits which may be persistent or replaced by lungs— so all vertebrates are basically chordates.
But all chordates are not vertebrates — for example, in Urochordata and Cephalochordata, notochord is persistent throughout life and is never replaced by vertebrate column. Hence urochordates and cephalochordates are chordates but not vertebrates.
Chapter 1 Life And Its Diversity Life And Its Diversity Descriptive Type Questions And Answers :
Class 9 Life Science Chapter 1 Question Answer WBBSE
Question 1. Define life. Write some characteristics of living beings.
Answer:
Life :
Life is unique, complex cellular organisation of molecules and the cells themselves that shows various types of chemical reactions which lead to availability of energy, growth development, responsiveness, adaptation and reproduction.
Characteristics of Living Beings :
(1) Protoplasm :
All living organisms contain a special type of viscous fluid called protoplasm. Huxley called it the “physical basis of life” because it has capability of performing vital functions. This is composed of carbon, hydrogen, oxygen and nitrogen.
(2) Cellular Organisation :
All living beings are composed of cell. Some are unicellular but some are multicellular. Cell is the structural and functional unit of life.
(3) Nutrition :
All organisms obtain food from environment material required for the metabolism and energy. Some are autotrophs but some are heterotrophs.
(4) Respiration :
Life is an energy-consuming process. This energy is obtained by breaking down energy-rich food substances through oxidation and it is called respiration.
(5) Metabolism :
The chemical changes through which living organisms acquire and utilize energy constitute metabolism. The process envolves anabolism and catabolism.
(6) Growth :
Young individuals grow in size. The growth is due to internal addition of protoplasmic materials by which cell enlarge and devide. Growth occures when anabolism exceeds catabolism.
(7) Definite shape and size :
Every living being has definite shape and size by which we can recognise it. A dog never looks like a monkey. A peepal tree differs from a mango tree.
(8) Execretion :
Metabolism produces a number of by-products which are useless to the body. The same are either expelled out of the body (in animals) or are stored inside ageing tissue (in plants)
(9) Movement and locomotion :
All living beings can shift either the whole of their body or a part of it from one place to another. It is called movement. When the whole of the body is displaced, it is called locomotion. Some movement occures due to purely internal forces and called autonomic movement. Others occur in response to external stimuli called paratonic movement.
(10) Irritability :
All the living beings respond to external stimuli such as cold, heat, wind, light, pinprick, etc. This is called irritability. Example – if a pin is pricked in a part ofour body, the part is immediately withdrawn. The plant bend in the direction of the light.
(11) Adaptability :
They are variations which help organisms to modify themselves according to changes in environment and specific requirements of their surroundings. Eg. birds have pneumatic bones and wings for flight and fishes have streamlined body to reduce water friction.
(12) Reproduction :
For the continued existence of the species, all living beings try to produce their own kind. The higher animal may produce young ones or may lay eggs from which hatch the young ones. :
(13) Ageing and death :
Every living being survives for a limited time and ultimately it dies. It has a definite lifespan.
(14) Life cycle :
Each individual passes through a definite life cycle of birth, growth, maturation, reproduction, ageing and death (80-100 years in humans, 200 years in Tortoise, more than 200 years in peepal trees).
Class 9 Life Science Chapter 1 Question Answer WBBSE
Question 2. How does the origin of life take place through non living objects?
Answer:
Chemical Origin of Life from non-living objects :
The formation of complex organic molecules from simpler inorganic molecules through chemical reactions in the ocean during the early history of the earth is known as chemical evolution.
The first theory of chemical evolution is given by Oparin and Haldane. According to them, the first formed molecules were small carbon-containing compounds like formal- dehyde and hydrogen cyanide. The small molecules reacted to form sugar, amino acid and nitrogen bases. Small molecules linked together to form nucleic acid and protein. They had ability of self-replication to form first living entity. Oparin suggested that organic compounds could have undergone a series of reactions leading to more complex molecules and forming ‘Coacervates’. It absorb and assimilate organic compounds from environment and became the first life form. The theory of abiogenesis has been proved experimentally by Stanley Miller. He created electric discharge in a closed flask containing CH,, H,, NH, and water vapour at 800°C. He observed formation of Amino Acid. In similar experiments, others observed formation of sugar, nitrogen bases, pigment and fats. For the emergence of life the presence of small organic molecules is not sufficient. There must be assortment of macro molecules including enzymes, proteins and nucleic acid having the self-replicating property. Synthesis of RNA monomers that can be formed from simpler precursor molecules.
Reproduction and energy processing are the two important properties of life forms. Protocells are vesicles fluid-filled compartments can be produced spontaneously when lipid and other organic molecules are added to water. It may be said that the protein coacervates are believed to have given rise to the first living organism.
Photosynthetic organisms are believed to have evolved near about 3500 million years ago. These primitive organisms released oxygen to the atmosphere as a byproduct of photosynthesis. The free oxygen in the atmosphere prevented the abiotic origin of life. So, it can be concluded that life did not evolve from the inorganic substances rather it arose from the pre-existing living organisms.
Question 3. What are the sources of variation of life? Explain.
Answer:
Sources of Variation in life :
Generally, no.two members of a population are exactly alike. The differences of characteristics between members of the same species are called variation. It is the raw material for evolution. Variation is observed both at the phenotypic level and at the genotypic level.
There are five basic mechanisms which cause variation at the genetic level. These are mutation, recombination, gene migration, genetic drift and natural selection.
Mutation :
A sudden heritable change in the characteristics of the organism. Mutation not only creates variation but also helps in maintaining variations within population. It also introduces new genes and alleles into the gene pool. The variability of genes in a gene pool becomes the raw material for evolutionary change.
Recombination :
Combining of two different genes which in future provide new genes. It takes place due to independent assortment of chromosomes during meiosis, crossing over and fertilization. Recombination acts as an agent of evolution.
Genetic drift :
The random changes in the allele frequency which is caused by chance alone are called genetic drift.
Natural Selection :
Selection is the consistent differences in the contribution of various genotypes to the next generation. It favours adaptation as a product of evolution.
Gene migration :
Sometimes few populations are completely isolated from the other population of the same species. If the migrating organisms breed within the new population, then the immigrants will transfer new alleles to the local gene pool of the host population. This is called gene migration.
Question 4. What are the different branches of Biology ? Define them.
Answer:
Biology :
Biology is mainly divided into two major branches, Botany and Zoology. In addition to these two broad categories, biology is divided into many other branches of study.
Biochemistry :
It is a complementary branch of biology. Chemical combination and their reaction in the protoplasm are guided by the principles of chemistry. Synthesis and functions of enzymes, hormones, etc. can be explained from the knowledge of chemistry.
Histology :
Deals with the structure and composition of tissue.
Genetics :
Branch of biology deals with the heredity and variation of living organisms.
Anatomy :
Deals with the gross structure of internal organs which can be seen with the naked eye.
Physiology :
Study of various life procecses in the living organism.
Ecology :
Study of reciprocal relationship between the organism and their environment.
Evolution :
The study of the descent of recent, more complex, advanced type of organism from simpler, earlier and primitive type, over a period of time.
Immunology :
The science that deals with the phenomena and causes of immunity(defence against diseases)
Molecular Biology :
Study of shape, organization.and orientation of molecules that make the cellular system as a unit.
Question 5. Write the application of physics, chemistry, mathematics, computer in biology.
Answer:
Biophysics :
A new branch of science developed with the-collaboration of physics with biology. Physiological proceses like osmosis, diffusion occuring in the living body can be explained with the help of physical science. Microscope is a very important instrument for the biologist in the contribution of physicist.
Biometrics :
This new branch has been developed from the knowledge of mathematics. Problems of growth, size of population and other various concepts of biology can be explained with the principles of mathematics.
Class 9 Life Science Chapter 1 Question Answer WBBSE
Cybernetics :
This branch has been formed in collaboration of biology with that of technology. The cyber-world provides the information regarding the gene and protein sequence that can be utilised by genetic engineers in developing transgenic organisms.
Question 6. Write the application of Biology in Agriculture, Medicine, Space Science and in other fields.
Answer:
The application of Biology in Agriculture, Medicine, Space science and in other fields: In agriculture :
Agricultural production gradually increased by the application of modern tools and techniques. The expansion of land for cultivation, increase of irrigation facilities, improved varieties of seed, crop rotation, using fertilizers, the productivity of crop increased. Improvement of crops in quality and quantity has been done by hybridization technique. It caused green revolution in India. New breeds are also developed by mutation method. Micropropagation method is also applied for the improvement of crops. Production of seedless fruits is the gift of biology.
In medicine :
Experimentation and research in biological field help us to know about different types of diseases, their pathogen, symptoms, mode of transmission and control methods. Serums, vaccines, hormones which are used in many of the diseases of man, are produced from animal body. Discovery of antibiotics and vaccines are not possible without the knowledge. Primary knowledge and the progress of the surgery largely depend on the animals. Cloning of organs, organ transplantation, Bypass surgery are possible only with the help of biology.
In Space Science :
During exploration of the planet, Cosmonauts keep the green alga chlorella in the space craft for oxygen and food. Space biology is very useful in the field of space research. It deals with the behaviour of living organism in outer space.
Forensic Science :
Scientific knowledge about DNA finger prints, blood typing are applied to deal with criminal activities, civil and criminal laws, solving the issue of paternity problem, can be used to detect a person killed in plane crash by analyzing DNA recovered from the ash.
Biotechnology :
Biotechnology is an integrated application of knowledge and technique of biochemistry, microbiology and genetics to derive benefit in the technological level involving microorganism.
It has area of recombinant DNA technology in gene cloning , producing vaccine, enzyme, interferon waste treatment, producing fuels, producing vitamins antibiotics, producing transgenic plants and animals.
Question 6. Write very brief history regarding the birth of modern taxonomy.
Answer:
History regarding the birth of modern taxonomy
Vedic literature mentions 740 plants and 250 animals. Susruta Samhita has classified animals into oviparous, viviparous, herbivores, carnivores, while plants have been divided into herbs, shrubs, trees, creepers. Hippocrates divided animals into groups like insect, bird, fishes and whales. Aristotle (384-322 BC) divided living being into animals, plants and human being. He is the father of “zoology”. Theophrastus (370-285 BC) is considered as the “Father of Botany”. He classified 480 plants is Historia plantarum, in herb, undershrub, shrub and trees. John Ray (1627-1705) proposed the concept of species as basic unit. Carolus Linnoaeus (1707-1778) is known as the “Father of taxonomy” and “Father of Nomenclature”. He introduced the system of binomial nomenclature.
Modern taxonomy considers a species to be product of evolution. It takes into consideration traits and evidences from all types of studies like morphology, anatomy, cytology, physiology, genetics, biochemistry, etc. The concept was developed by Julian Huxley (1940)
Question 7. Explain the 7 steps of taxonomic hierarchy.
Answer:
7 steps of taxonomic hierarchy
Arranging various taxonomic units in their proper descending order on the basis of their taxonomic ranks, is called taxonomic hierarchy.
In this hierarchy, the kingdom represent the category of the highest rank, while the species represent the category of basic rank. It consists of
(1) species — basic unit of classification
(2) genus — a group of closely related species
(3) family — it is an assemblage of closely related genera
(4) order — itis a taxonomic unit formed by grouping together the closely related families.
(5) class — the order of plants and animals constitute class.
(6) divison — the class together constitute Division in plants and Phylum in animals.
Question 8. Write the systemic position of Human and Mango.
Answer:
systemic position of Human:
Kingdom — Animalia
Phylum — Chordata
Class — Mammalia
Order — Primate
Family — Hominidae
Genus — Homo
Species — Sapiens
Systemic position of Mango:
Kingdom — Plantae
Division — Spermatophyta
Subdivision — Angiospermae
Class — Dicotyledonae
Ordar — Sapindales
Family — Anacardiaceae
Genus — Mangifera
Species — indica
Question 9. Explain briefly binomial nomenclature with an example.
Answer:
B inomial nomenclature with an example
A system of nomenclature in which the scientific name of an organism consists of two parts, first part is the generic name and the second part is the specific name.
Eg : Gossypium herbaceum (cotton). Here Gossypium is the generic name and herbaceum is the specific name.
This system of nomenclature was introduced by Carolus Linnaeus in 1753 in his book “Species Plantarum”.
Generic name should come first and must begin with capital alphabet. Specific name should begin with small alphabet. The scientific name must be either underlined or written in italics. The name of the author who first decribed the species should be written in specific name.
eg. Homo – spiens linnaeus
Class 9 Life Science Chapter 1 Question Answer WBBSE
Question 10. Write the significance of Binomial Nomenclature.
Answer:
Significance of Binomial Nomenclature :
(1) The system proved to be so convenient that it was universally accepted by the Biologist and approved by the International Code of Botanical Nomenclature (ICBN).
(2) It has avoided the confusion usually created by the usage of local name.
Question 11. Name five kingdoms of life.
Answer:
Five kingdoms of classification were proposed by R.H. Whittakar (1969).
There are three main criteria for this classification :
(1) Complexity of cell structure
(2) Complexity oforganism
(3) Mode of nutrition DNA strand Plasmid
The five kingdom of life are :-
(1) Monera
(2) Protista
(3) Plantae
(4) Fungi
(5) Animalia
Question 12. Write three salient features of Monera.
Answer:
Three salient features of Monera
(1) Prokaryotes with incipient unorganised Nucleus
(2) Absence of membrane-bound cell organelles
(3) Rigid cell wall composed of polysaccharide units eae eal
(4) They are useful as well as harmful.
Example — Bacteria and Cyanobacteria. Baden
Question 13. Write three salient features of Protista.
Answer:
Three salient features of Protista
(1) Unicellular organism.
(2) Cell organization — Eukaryotic
(3) Presence of membrane-bound cell organelles
(4) Presence of Mitosis, Meiosis and Sexual reproduction in life cycle.
Example — Amoeba, Paramoceium, Diatoms.
Question 14. Write three salient features of Fungi.
Answer:
Three salient features of Fungi
(1) Multicellular organism (yeast is unicellular)
(2) Eukaryotic heterotrophs
(3) Cell wall of fungal cellulose (Chitin)
(4) Reserve food is glycogen
(5) Nutrition by absorption
(6) They are useful as well as harmful and Cause diseases in plants, animals and humans.
Example — Yeast, Mushrooms, Puccinia.
Question 15. Write the features of kingdom – Plantae and Animalia
Answer:
(1) Multicellular
(2) Eukaryotes with Cellulose walls
(3) Photosynthetic organism. (Producers)
(4) Main source of oxygen, organic food and food energy for all organisms.
Example :- Algae, Bryophyta, Angiosperms
Features of kingdom-Animalia
(1) Multicellular, Eukaryotic organism.
(2) Consumers with heterotrophic, holozoic nutrition
(3) Presence of locomotory organs
(4) Tissue system – such as muscular, nervous, etc.
Example — worms, insects, birds, mammals.
Class 9 Life Science Chapter 1 Question Answer WBBSE
Question 16. What are the characteristics of Algae ?
Answer:
Characteristics of Algae
(1) Simplest multicellular green plants
(2) Mostly aquatic-fresh as well as marine water
(3) Having chlorophyll, so main aquatic producer
(4) Mostly filamentous, branched or unbranched
(5) Thallus like body, not differentiated into root, stem and leaf.
(6) Based on photosynthetic pigment, classified as-
Chlorophyceae (green alge)
Phaeophyceae (Brown alge)
Rhodophyceae (Red alge)
Question 17. Write the main features of Bryophyta.
Answer:
Characteristics of Bryophyta :
(1) First group of land plants
(2) Non-vascular and non-flowering plants
(3) known as amphibians of plant kingdom.
(4) Plant body small, green, delicate.
(5) Plant body differentiated into leaf and stem
(6) Rhizoides on lower surface for fixation and absorption. True roots are absent.
(7) Reproductive organs are Antheridium (male) and Archegonium (female organ)
(8) Alternation of generation takes place.
Example — Riccia, Marchantia, Mosses, etc.
Question 18. Write the characteristics of Pteriolophyta.
Answer:
Characteristics of Pteriolophyta
(1) First group of vascular land plants
(2) Non-flowering vascular embryophytes
(3) Presence of True roots, stem and leaves.
(4) Small, herbaceous or shrub like independent plant body.
(5) Xylem without vessels and phloem without sieve tube.
(6) Reproduction by vegetative, asexual and sexual method.
(7) Presnce of alternation of generation.
Example — Lycopodium, Selaginella
Question 19. What are the characteristics of Gymnosperm ?
Answer:
Characteristics of Gymnosperm
(1) Flowering plants (Phanerogams)
(2) Plants with naked seed.
(3) Plant body is adult sporophyte, mostly trees.
(4) Well-developed vascular tissue, xylem without vessel and phloem without Sieve tube and companion cell.
(5) Leaves mostly dimorphic —green photosynthetic foliage and non-green small scaly leaves.
(6) Stem woody and branched (except cycas).
(7) Presence of Cones, male and female separate.
(8) Alternation of generations present.
Example — Cycas, Pinus, Ephedra.
Question 20. What are the characteristics of angiosperm ?
Answer:
Characteristics of Angiosperm—
(1) Most evolved and specialized group of plant kingdom.
(2) Flowering plants, bears fruits.
(3) Flower as reproductive organs with closed carpel.
(4) Double fertilization and triple fusion.
(5) Well-developed conducting tissue-xylem & phloem.
(6) More complex and better adapted for terrestrial condition.
(7) Distinct alternation of generations.
(8) Classified into Dicotyledones and Monocotyledons.
Question 21. Write the differences in Monocot and Dicot plants.
Answer:
Differences in Monocot and Dicot plants
| Monocots | Dicots |
| 1. Adventitious root system. | 1. Tap root system. |
| 2. Parallel venation in leaf. | 2. Reticulate venation. |
| 3. Always alternate Phyllotaxi. | 3. Alternate , opposite or whorled. |
| 4. One cotyledon. | 4. Two cotyledones. |
| 5. Trimerous flower. | 5. Tetra or pentamerous flower. |
| Eg : maize, wheat, rice, coconut. | Eg : chinarose, mango, neem. |
Class 9 Life Science Chapter 1 Question Answer WBBSE
Q.22. Write down the characteristics of Phylum Protozoa.
Answer:
Phylum — Protozoa:
Characteristics —
(1) There are minute, mieroscopic in size and can not be seen with the naked eyes.
(2) These are unicellular or acellular or non – cellular,
(3) They may be free-living or parasite.
(4) Protoplasm is distinguished into outer ectoplasm and inner endoplasm.
(5) Nucleus may be one, two-or many in different protozoans.
(6) Locomotory organs are pseudopodia, flagella and cilia.
(7) Nutrition may be holozoic.
(8) Respiration takes place through the general surface of the body.
(9) Excretion takes place either through general surface of the body or through contractile vacuole.
(10). Respiration may be asexual or sexual or both.
Example — Amoeba, Paramecium, Euglena, Plasmodium.
Question 23. Classify animal kingdom.
Answer:
Classification of Kingdom Animalia :
The animal kingdom is divided into two subkingdoms : Non-chordata and Chordata
| Nonchordata | Chordata |
| 1. Notochord is absent. | 1. Notochord is present. |
| 2. Visceral cleft is absent. | 2. Visceral cleft present in pharynx. |
| 3. Central nervous system ventral solid,double. | 3. Central nervous system dorsal, hollow, tubular. |
| 4. Heart is dorsal. | 4. Heart is ventral. |
| 5. Tail is unsegmented. | 5. Post anal, metamerically segmented tail. |
Question 24. Write down the characteristics of Porifera.
Answer:
Phylum — Porifera :
1. These are sedentary. found in water. f Outgoin
2. These are multicellular animals but cellular level of organisation.
3. Body bears numerous minute pores, the ostia.
4. Skeleton is made up of calcareous spicules and of sponge in fibres.
5. Respiration, excretion, nutrition takes place with the help of water current.
6. sexual reproduction takes place by budding or gemmules.
7. Sexual reproduction by gamets, i.e., sperm and ova.
8. They have the power of regeneration.
Example — Spongilla, Scypha, Euplictella.
Question 25. Write down the characteristics of Cnidaria.
Answer:
Phylum—Coelenterata (Cnidaria)
1. Multicellular animals with tissue grade of organisation.
2. They are radially symenetrical and diploblastic.
3. Organs are entirely absent.
4. Digestion is partly intracellular, partly extracellular.
5. Coclenteron represents the digestive tube.
6. Nervous system is primitive.
7. Their skeleton forms corals and coral reefs. :
8. Special stinging cells called Nematoblasts or Cnedoblist are present in groups in tentacles. These are used for food capture and defence.
9. Reproduction takes place by budding and games.
Example — Hydra, Sea anemone, Physalia, Aurelia,
Question 26. Write down the characteristics of Platyhelminthes.
Answer:
Phylum — Platyhelminthes :
1. Acoelomate (true body cavity absent).
2. Organ level of organisation.
3. Bilateral symmetry, dorsoventrally flattened.
4. Excretory organs are flame cells.
5. Skeletal, criculatory or respiratory organs are absent.
6. Hermaphrodite animals.
7. Nervous system is represented by a pair of anterior ganglia and 1-3 pairs of longitudinal nerve cords.
Example — Liver fluke, Tapeworm.
West Bengal Board Class 9 Life Science Question and Answers
Question 27. Write down the characteristics of Aschelminthes.
Answer:
Phylum — Aschelminthes:
1. Multicellular, long, cylindrical, unsegmented worms.
2. Bilateral symmetry and Triploblastic.
3. They are Pseudocoelomate i.e. a coelom without lining of mesoderm.
4. Circulatory and respiratory organs are absent.
5. Excretory organs are protonephridia.
6. Sexes are separate, i.e., dioecious.
7. Digestive system are mouth, pharynx and intestine.
8. Most of them are parasites. “Ascaris
Example — Ascaris, Filaria worm.
Question 28. Write down the characteristics of Annelida.
Answer:
Phylum — Annelida:
1. These are elongated, cylindrical, triploblastic and metamerically segmented worms.
2. Organ system level of organization.
3. Locomotory organs are Setae.
4. True coelom present (coelomate).
West Bengal Board Class 9 Life Science Question and Answers
5. Circulatory and nervous system are present.
6. Excretory organs are Nephridia.
7. May be unisexual or bisexual. Earthworm
Example — Earthworm, Neries, Leech.
Question 29. Write down the characteristics of Arthropoda.
Answer:
Phylum — Arthropoda-
1. It is the largest and comprises of about 80% of the total species of the animals.
2. These are multicellular, triploblastic, bilateral symmetry.
3. Coelom is filled with blood (haemocoel).
4. Jointed legs.
5. Exoskeleton is in the form of chitin.
6. Body vascular system is open type.
7. Excretion takes place through green gland and malpighian tubules.
8. Well developed nervous system.
9. Usually dioecious.
10. Body is divided into head, thorax and abdomen.
Example — Cockroach, Grasshopper, Dragonfly.
West Bengal Board Class 9 Life Science Question and Answers
Question 30. Write down the characteristics of Mollusca.
Answer:
Phylum — Mollusca
1. Body is soft with variable shapes.
2. Triploblastic, bilateral symmetry and Coelomate.
3. Mantle, a thin fold of integument, serves respiration and protection.
4. Alimentary canal is complete.
5. Open type of circulatory system
6. Respiratory organs are ctenidia, gills, mantle and air sacs.
7. Excretion takes place by kidneys.
8. Well-developed Nervous system with a pair of ganglia and nerves.
Exampie — Octopus, Snail, Oysters, Cuttlefish.
Question 31. Write down the characteristics of Echinodermata.
Answer:
Phylum — Echinodermata
1. It includes the animals which bear spine-like structures on their integuments.
2. Triploblastic and coelomate.
3. Organ system level of organisation.
4. Integument with calcareous spines.
5. Simple nervous system.
6. Respiration through tube feet, respiratory tree and brutal.
7. Sexes separate and possess power of regeneration.
Example — Starfish, Sea cucumber, Sea urchin
Question 32. Write down the characteristics of Phylum Chordata and their classes with example.
Answer:
Phylum — Chordata :
1. Presence of notochord.
2. Paired gill slits are present at any stage of life.
3. Dorsal tubular nerve cord is always present.,
Phylum chordata has been divided into five classes :
West Bengal Board Class 9 Life Science Question and Answers
1. Class — Pisces
(1) Aquatic animals, fresh water as well as marine
(2) Cold blooded or Poikilo thermic
(3) Gills for respiration
(4) Exoskeleton in the form of scales or bony plates
(5) Paired and unpaired fins for locomotion
(6) Two chambered heart, oviparous
(7) lateral line sence organ present.
Example — Scoliodon, Shark, Labeo, etc.
2. Class — Amphibia
(1) Cold blooded animals, skin is soft, moist and glandular
(2) Eyelids are movable and nictitating membrane is present
(3) RBC are nucleated
(4) Respiration takes place through skin, buccal cavity and lungs
(5) External ear is absent. Oviparous animals.
Example — Frog, Toad, Salamander.
3. Class — Reptilia
1. Cold blooded animals, body is covered with Cornified skin.
2. These are tetrapods (having four legs) and Pentadactyle (having five fingers).
3. Lungs for respiration but in certain turtles cloacal respiration.
4, Internal fertilisation, mostly oviparous.
Example — Lizard, Snake, Turtle, Tortoise.
4. Class — Aves.
1. Warm blooded vertebrates
2. Arboreal habitat
3. Fore limbs modified for flying and hind limbs for walking.
4. Four chambered heart
5. Hollow bones, one ovary absent.
Example — Duck, Pigeon.
Class 9th Life Science WBBSE
5. Class — Mammalia
1. Constant body temperature
2. Hair, ear pinna, mammary glands are present
3. RBC non-nucleated except camel
4. Four-chambered, well-developed heart
5. Viviparous — give birth to young ones
6. Internal fertilization.
7. The mother suckles her young ones on milk secreted by special glands called mammary glands.
Example — Cat, Dog, Monkey, Man, Tiger.
Question 33. Discuss about the metabolism property of living organisms. What is irritability ?
Answer:
Metabolism :
The sum total of the biochemical changes involved in a two-fold process of waste and repair of the protoplasm is known as metabolism. The constructive anabolic phase is the one in which complex substances are formed and the destructive, catabolic phase is the one where substances are broken down and discharged. These processes occur constantly within the protoplasm of living organisms, where uptake and use of energy occurred.
The constructive (repair) phase is one in which food materials are built up into more complex substances and the process is known as anabolism, (GK, Ana = upper, balls = throw), while the other phase (waste) is destructive and is known as catabolism (cata =below, balls = throw). For instance, photosynthesis is an anabolic process in which sugar is formed in the cell and potential energy is captivated within the sugar molecule. Respiration is a catabolic process in which the captivated potential energy is released from the sugar molecule as kinetic energy with the oxidation of the sugar molecule.
Irritabillity :
The capacity to respond through internal changes to various exciting agents is commonly known as irritability. The changed environmental condition which excites responds to the living organism is known as stimulus, during which a living body reacts called as response. Thus the ability of living body in responding is known as irritability.
Question 34. What are the applied branches of biology ?
Answer:
Emergence of new branches of Biology :
Biology has enormous applications in other branches of science. It forms an important part of —
(1) Veterinary science — It deals with treatment and surgery of animals.
(2) Marine biology — It deals with the study of life in the sea.
(3) Horticulture — It deals with science of growing flowers, fruits, vegetables, ornamental plants.
(4) Sericulture — It is the technique of producing silk by rearing silkworms.
(5) Pisciculture — It deals with technique of growing fish.
(6) Cloning — It is the rapidly advancing branch of biotechnology introducing a body cell for producing an individual.
(7) Molecular biology — It is the science which deals with interpreting biological events in terms of the molecules in the cell.
(8) Biotechnology — It deals with the application of biological processes in technology such as biogas production from organic wastes; production of insulin through bacteria.
(9) Space biology — It the study of problems of living things in outer space.
(10) Nuclear biology — It is the study of effects of radioactivity on living things.
(11) Bioengineering — It include techniques like making of artificial limb, joints and other parts of from metals or plastic.
Question 35. Discuss the application of biology in genetics.
Answer:
In genetic engineering programmes, mapping of the whole genome of an organism has been possible. Synthesis of many products was possible through genetically engineered cells. Recombinant DNA technology aided in detecting genetic diseases and its cure. Production of vaccines of malarial and viral diseases; production of hybrid plants using protoplast fusion techniques through intergeneric crosses, production of encapsulated seeds, disease-resistant plants, herbicides, stress-resistant plants, essential oils, alkaloids, pigments are possible now. Use of biofertilizers resulted in greater yield of agricultural crops. Bacterial plasmids are being used to abate pollution, treat sewage and domestic wastes.
These plasmids are capable of degrading complex polymers into non-toxic forms. Technologies have been developed to seek an alternative source of energy from biomaterials generated from agricultural, industrial, forestry and municipal sources. Plant weeds are being used for production of biogas used for cooking and lighting purposes.
Tissue culture techniques help in culture of micro-organisms or plant or animal cells or tissues and organs in artificial media. Gene technology is used in the production of recombinant DNA and gene cloning. The use of insulin for diabetes and interferon for treatment against some tumour viruses has been possible. Monoclonal antibodies are used for diagnosis of various diseases. DNA fingerprinting and auto-antibody finger printing are used in the identification of criminals in murder and rape cases. Biotechnologists are producing organic compounds the ethanol, acetone, butanol, gluconic acid, enzymes, antibiotics like penicillin, streptomucin. Microbes are developed to be used as biopesticides and biofertilisers.
Application of gene therapy, anmniocentesis, genetic counselling cloning have gained importance in the present millennium. Using transgenic technique a genetic disease may be cured. Amniocentesis technique may be applied to understand the chromosomal abnormality of the foetus.
Class 9th Life Science WBBSE
Question 36. Mention the rules of writing scientific name of an organism.
Answer:
Rules of Nomenclature :
The following conventions of nomenclature may be noteworthy :
(1) Names given to plants or animals prior to publication of ‘systema nature! (10th edition) are not acceptable.
(2) Names should be written in Latin or its derivative.
(3) Both the genetic and specific names must be written in Italics, the genus starts with a capital letter and the species begins with a small letter, e.g., Solanum tuberosum (Potato).
(4) The specific name is usually a descriptive one, e.g., Hygrophilia spinosa (a plant with spines).
(5) Only a single valid name for each kind of organism is permitted. When two or more names are given correctly to a plant or animal, then the name used by the first author (the author who described the plant or animal first) is approved and the others would be treated as synonyms. This is known as the Law of Priority.
(6) The species must be mentioned for a newly established genus.
(7) The name of the author who first described a species is also added to an abbreviated from after the name of the species, e.g. Mangifera indica Linn. Here Linn. refers to the author Linnaeus who first described the species.
(8) In case of animals the suffix-idea must be added to the family name and suffix-inae to the sub-family name.
Question 37. Discuss the salient features and examples of the subphylums cephalochor data (Acraniata) and Vertebrata (Craniata).
Answer:
Subphylum Cephalochordata (Acranita) :
Salient features :
1. Notochord extends from head to tail.region and is persistent throughout life.
2. Fish like marine animals.
3. ‘V’ shaped myotome muscles are present.
Example : Amphioxus sp, Asymmetron sp.
Subphylum Vertebrata (Craniata) :
Salient features :
1. Presence of endoskeleton made of bones and cartilages.
2. Presence of cranium or brain box that accommodates brain.
3. Presence of dorsal vertebral column formed of vertebrae.
Example : Shark, Rohu, Frog, Lizard, Birds, Guineapig, etc.
Question 38. Compare any three features of all the five kingdoms of life.
Answer:
Comparing features of all the five kingdoms of life
| Monera | Protista | Fungi | Plantae | Animalia | |
| 1. Nature of | Prokaryotic | Eukaryotic, | Plant body | Multicelluar, | Multicellular. |
| of Cell and | unicellular, | unicellular | of fungi called | most of them | heterotrophic, |
| cellular orga- | may be | may be | mycelium made | are chlorophyll | eukaryotes. |
| nization | filamentous | colonial | up of fine thre- | containing | cell wall |
| Membrane | cell wall | ads called hyp- | autotrophic | absent. | |
| bound cell | present, | hae, cell wall | eukaryotic | ||
| organelles | some | made up of fu- | cell wall | ||
| absent,e.g. | protists, | ngal cellulose | composed of | ||
| Mitochondria | or chitin | cellulose, | |||
| Golgi bodies, | Multicellular | single central | |||
| etc. | achlorophyllous | vacuole | |||
| In case of | present, | ||||
| Mycoplasma | cell organelles | ||||
| Cell well absent | present, are | ||||
| Instead of cell- | all double | ||||
| ulose cell wall | membraned. | ||||
| is made up of | |||||
| Peptidoglycan | |||||
| or murein | |||||
| 2. Metabolic process | Both | In unicellular | Heterotrophic, may be | Autotrophic | Heterotrophic |
| autotrophic | algae photosynthetic | may be | organisms, | Mode of | |
| and hetero- | nutrition occurs, | decomposers | can able to | nutritiond | |
| trophic mode | e.g. Dinoflagell | or saprophytes | photosynth- | generally | |
| of nutrition | ate. In Amoeba | a few may be | esize | holozoic. | |
| noted. | holozoic and in | parasite. | |||
| Entamoeba | |||||
| absorptive | |||||
| nutrition are noted | |||||
| 3. Ecological role | Some of | Dual nutrition | Live their lives | Lot of diveris- | Include large |
| them are | noted called | as saprophytes | ity noted grows | variety of | |
| nitrogen | mixotrophic | or parasites, | on different | animals, living in | |
| fixing; some | nutrition, | saprophytic | habitats act | different | |
| Monerians | they are | fungi derive | as producers | environments act | |
| perform the | called as | their food | as consumers. | ||
| functions of | plant animal. | matter from | |||
| ammonifica- | dead, decaying | ||||
| tions, | organic matters | ||||
| nitrification | |||||
| and denitrifi- | |||||
| cation. | |||||
| Two common | Bacterium | Paramaecium | Penicillium | Pinus, Hibiscus | Earthworm Human |
| examples | Anabaena | Euglena | Aspergillus | (China rose) | (Homo sapiens) |
Question 39. Discuss the salient features and examples of divisions Agnatha and Gnathos tomala.
Answer:
Division Agnatha :
(A = without; ganathos = Jaw)
(Jawless animal)
Salient features :
1. Mouth is circular (Cyclostomata : Cyclos = circular; stoma = mouth).
2. Absence of jaws surrounding mouth.
3. No paired fins and fins are without fin rays.
Example : Lamprey (Petromyzon marinus )
Hag fish (Myxine glutinosa)
Division Gnathostomata :
(Gnathos = Jaw; stoma = mouth)
(Animals with jaw)
Class 9th Life Science WBBSE
Salient features :
1. Mouth is guarded by upper and lower jaw.
2. Skeleton is mostly made of bones.
3. Respiration occurs by gills or lungs.
Example: Fish, Amphibia, Reptilia, Aves, Mammalia.
Class 1. Chondrichthyes (Gr. chondros = Cartilage; icthyes = Fish)
(Fishes having cartilaginous skeleton)
Salient features :
1. Endoskeleton completely cartilaginous; bone absent.
2. Gill slits are without aperculum; mouth ventrally placed.
3. Marine animals where body is covered with placoid scales; no air bladder.
Example : Dogfish/shark (Scoliodon sp.)
Sting ray (Trygon sp.)
Electric ray fish can cause electric shock for defence.
Question 40. Explain the basis of classification of animals.
Answer:
Basis of Classification of Animals : A few fundamental bases of classifying animals are given below.
I. Levels of Organization :
(1) Cellular level :
In case of cellular-level organization, a single cell is responsible for all the metabolic activities. Cellular level organization is present in some of the animals like sponges.
(2) Tissue level :
In case of tissue-level organization, a group of cells is responsible
for all the metabolic activities, e.g. cnidarians.
(3) Organ level :
In case of organ-level organization, some specialized organs are
present for some specific functions, e.g. platyhelminthes.
(4) Organ System level :
In organ system level organization, complex organ systems are present for various functions, e.g. mollusca, chordate.
II. Symmetry :
(1) Asymmetrical :
Some of the animals are almost asymmetrical. Their body cannot
be divided into two equal halves from any plane, e.g. sponges.
(2) Radial Symmetry :
In case of radial symmetry, any plane passing through the
central axis divides the body into two identical halves, e.g. cnidarians, oo sae echinoderms, etc.
(3) Bilateral Symmetry :
In case of bilateral symmetry, the body can be divided into two identical halves only through a single plane, e.g. annelida, arthropoda, etc.
III. Body Organization :
1. Diploblastic :
When the cells are arranged in two embryonic layers, the animal is called a diploblastic animal. The two layers are——ectoderm and endoderm.
Example : cnidarians :
Class 9th Life Science WBBSE
2. Triploblastic :
When the cells are arranged in three embryonic layers, the animal is called triploblastic animal. The three layers are——ectoderm, mesoderm and endoderm.
Examples : platyhelminthes to chordates.
IV. Coelom :
The body cavity which is lined by mesoderm is called coelom. Animals may be-
(1) Coelomates :
If coelom is present, the animal is called coelomate, e.g. annelids, molluscs, arthropods, echinoderms, hemichordates and chordates.
(2) Pseudocoelomates :
If the body cavity is not lined by mesoderm but the mesoderm is present as scattered pouches in between the ect oderm and endoderm, the animal is called pseudocoelomate, e.g. aschelminthes.
(3) Acoelomates :
When the body cavity i is absent, the animal is called acoelomate, e.g. platyheminthes.
V. Notochord :
Notochord is a mesodermally derived rod-like structure. It is formed on the dorsal side during embryonic development in some animals.
(1) Chordates :
If notochord is present then the animal comes under chordates.
(2) Non-Chordates :
An animal without notochord is called non-chordate, e.g. porifera to echinoderms.
Question 41. Distinguish between Algae and Fungi.
Answer:
Difference between Algae and Fungi
| Alagae | Fungi |
| 1. Mostly aquatic, some are terrestrial. | 1. Mostly terrestrial, some are aquatic. |
| 2. Light is necessary for their growth. | 2. They can grow either in presence |
| or absence of light. | |
| 3. Algae possess chlorophyll in addition | 3. Fungi do not possess chlorophyll |
| to other pigments. | and other pigments. |
| 4. Algae are autophytes. | 4. Fungi are heterophytes. They may |
| be either parasite or saprophyte. | |
| 5. Body is composed of parenchymatous | 5. Body composed of pseudoparenc- |
| tissue. | hymatous tissue, made up of fine tub- |
| ular hyphal cells. | |
| 6. The principal cell wall material is cellul-ose. | 6. The principal cel wall material is ctutin. |
| 7. Algal body may be unicellular or mul- | 7. Fungal body may be unicellular or |
| ticellular. In case of multicellular algae, the | multicellular. In case of miriticellular |
| filamentous body may be unbranched | fungi, the body is composed of myceli- |
| or branched. | um. Hyphae collectively forms mycel- |
| ium. | |
| 8. Starch is the main storage food. | 8. Glycogen is the main storage food. |
Question 42. Distinguish between Bryophta and Pteridophyta.
Answer:
Difference between Bryophta and Pteridophyta
| Bryophyta | Pteridophyta |
| 1. Non- vascular cryptogamic plants. | 1. Vascular cryptogamic plants. |
| 2. Plant body is the ha plod (n) garn- | 2. Plant body is the diploid (2n) sporo- |
| et ophyte. | phyte. |
| 3. Gametophytic plants possess rhizoids. | 3. Gametophtic plant does not possess |
| rhizokJs, except certain Ptendophytes | |
| (eg- Dryoptens). | |
| 4. Sporophytic plants are not differen- | 4. Sporophytic plants differentiated into |
| tiated into root, stem and leaves. | root, stem and leaves. |
| 5. Sporophytcs are always dependent | 5. Sporophytcs are always independent. |
| upon the gametophyte. |
Question 43. Distinguish between Angiosperms and Gymnosperms.
Answer:
Difference between Angiosperms and Gymnosperms
| Angiosperm | Gymnosperm |
| 1.The reproductive organ of angiosperm | 1. The reproductive organ of gymnosperm is cone |
| is flower; it is composed of calyx, corolla, | or stroWus. Flowers are unisexual and naked, |
| ardroeoum and gynoedum. Rowers are | calyx and corolla absent. Perianth generally |
| unisexual or bisexual. Perianth may be present. | absent, exception – Gnetum. |
| 2. In case of unisexual flower, calyx, co- | 2. The male flower (mate cone) of gymnosperm |
| rolla and androedum or gynoedum and | is composed of only microsporophyll equivalent |
| in case of txsexual flower calyx, coroia, | to stamen and the female flower 6 composed of |
| andrcedum and gyncecium are present. | only megasporophyll equivalent to carpel. |
| The microsporophyils are compactly arranged | |
| spra&y over a central axis formrg a cone like | |
| structure- the male cone and the megaspocoph- | |
| ylls in most cases are compactly arranged to | |
| form the female cone (exception-Cycas). | |
| 3. In case of angiosperms, except wind, | 3. In case of gymnosperms, poinabon occurs |
| pohnabon also occurs by means of other | only by means of wind. |
| agents. | |
| 4. The carpel s composed of ovary, style | 4. The structure of the carpel is very simple. |
| and sigma. Ovules lies within the ovary. | The carpel is not composed of ovary, style and |
| Herce seeds remain covered by fruit | stgmsa (a so called style present in Gnetum). |
| (closed seeded). One or many carpels take | The megasporangium or ovule rot formed within |
| part m the formation of fruit. | the ovary, reman exposed. Hence seeds remain |
| exposed (naked seeded). The naked seeds lies | |
| over the megasporophylls. | |
| 5. The pollen grains are transferred to the bp | 5. Due to poltnaton the mcrospores (polien grai- |
| of the stigma by help of different agents but | ns) are directly transferred into the ovule. |
| never falls over the ovules directly. The pollen | |
| tube formed from the pollen grans gradually | |
| penetrates the style and ovary and ultimately | |
| reaches the ovule. | |
| 6. The endosperm tissue formed during double | 6. Ther endosperm is haptetd (n) in gymnosperms |
| fertilization is tnploid (3n), because a hapDid | because endosperm s a part of the female |
| male gamete (n) unties with a dpkod defintve | gametophyte formed before fertilization. But |
| nucleus (2n) to form finally the endosperm. | endosperm s partly formed after fertilization m |
| case of Gnetum. |
Class 9th Life Science WBBSE Question 44.
Compare between Cnidaria and Ctenophora.
Answer:
Comparison between Cnidaria and Ctenophora :
Similarities:
1. Both of them are diploblasitc
2. Almost all of them are marine animals.
Dissimilarities:
| Cnidaria | Ctenophora |
| 1. Presence of Cnidobtast cell | 1. Presence of colloblastcetl. |
| 2. Presence of namatocyst. | 2. Presence of comb plates. |
Question 45. Compare between Platyhelminthes and Aschelminthes.
Answer:
Comparison between Platyhelminthes and Aschelminthes
Similarities:
1. Almost all of them are parasitic.
Differences :
| Platyhelminthes | Aschelminthes |
| 1. Bodytape like, Flat, | 1. Body cylindrical,elongated. |
| 2. Alimentary canal is eittar absent | 2. Alimentary canal is complete. |
| Or incomplete. | |
| 3. Mostly hermapbrotfits (bisexu&l). | 3. AH a re unisexual (sexes are separate). |
Question 46. Compare between Annelida and Arthropoda.
Answer:
Comparing between Annelida and Arthropod
| Platyhelminthes | Aschelminthes |
| 1. Body segments ring like and separated | 1. Body segments are not separated by |
| by septum. | septum. |
| 2. Body is not covered by hard exoskel- | 2. Body is covered by hard chitinous |
| eton. | exoskeleton. |
| 3. No jointed appendages. | 3. Appendages are joined with the body by arthrodial membrane. |
| Haemocoel absent, | 4. Haemocoel is present, |
| g. Earthworm, Leech. | e.g. Prawn, Cockroach. |
Question 47 Distinguish between — (a) Chondrichthyes and Osteichthyes, (b) Amphibia and Reptilia.
Answer:
Difference between Chondrichthyes and Osteichthyes :
| Angiosperm | Gymn-osperm |
| 1. Endoskeleton cartilaginous. | 1. Endoskeleton mostly bony, |
| 2. Mouth ventrally placed in the head. | 2. Mouth at the bp of the head. |
| 3. Air hladded abseht. | 3. Air bladder present. |
| 4. Gills not cohered by operculum. | 4. Gills covered by operculum. |
Difference between Amphibia and Reptilia :
| Amphibia | Reptilia |
| 1 Fore limb with four digits and hind limbwith five digits—digits are without claws. |
1. Both fore limbs and hind limbs are provided with five clawed digits. |
| 2 Skin glandular, naked and moist. | 2. Skin dry, with homy epidermal scales. |
| 3 Heart three chambered. | 3. Heart three and half chambered(ventricle incompletely divided); |
| only incrocodile heart is four chambered (ventricle completely divided). |
Question 48. Distinguish between Cryptogamae and Phanerogamae.
Answer:
Difference between Cryptogamae and Phanerogamae
| Features | Cryptogamae | Phanerogamae |
| 1. Seeds | Do not produce seeds. | Produce seeds. |
| 2. Vascular system | May or nwy not be present. | Always present, |
| . 3. Fertilization | Externa: water serve as metfum. | Do not wed external water. |
| 4. Evolutionary status | Primitive. | Advanced |
| S Example | Algae, muss, fern. | Fine, mango. |
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