Optionals IAS Mains Botany: Questions 348 - 356 of 422

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Question 348

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Appeared in Year: 2017

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Essay▾

Evidences of organic evolution.

Explanation

Evidences of Organic Evolution

  • Organic evolution the process in which the changes occur in the population of organism in response to environmental changes.
  • There are many evidence of organic evolution

Evidence 1

Palaeontology

  • Palaeontology is scientific study of fossils.
  • Fossils provide strongest and direct evidence that support the theory of organic evo

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Question 349

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Appeared in Year: 2017

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Describe the methods of breaking seed dormancy. Trace the physiological changes involved during seed germination.

Explanation

Methods of Breaking Seed Dormancy

What is seed dormancy?

  • Seed dormancy is an adaptation that prevents seed from germinating during unsuitable ecological condition.
  • There are many methods to break seed dormancy some of them are natural while some of them are natural.
Methods of breaking seed dormancy

Methods of Breaking Seed Dormancy

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Natural Methods

  • Over-ripening of the fr

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Question 350

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Appeared in Year: 2017

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Enumerate the Sporophytic and gametophytic feature of psilotum. Comment on systematic position.

Explanation

Psilotum

Sporophytic and gametophytic feature of psilotum

Sporophytic and Gametophytic Feature of Psilotum

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Sporophytic Feature

  • Sporophytic body composed of subterranean Rhizome and dichotomously branched aerial shoots.
  • The rhizome is cylindrical, prostrate and dichotomously branched.
  • Sometimes it is seen the branching trends to become lateral or irregular due to injury in the region of

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Question 351

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Appeared in Year: 2017

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Describe with illustrations about chromosomal behaviour during meiosis with translocation, inversion and duplication.

Explanation

Meiosis

Meiosis is a process where single cell divide twice and produce cells containing half of the original genetic material.

Meiosis I

Chromosomal behaviour during meiosis

Chromosomal Behaviour During Meiosis

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Meiosis II

Chromosomal behaviour meiosis II

Chromosomal Behaviour Meiosis II

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Chromosomal Behaviour

  • In meiosis two rounds of chromosome segregation occur but only after single replicat

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Question 352

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Appeared in Year: 2017

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Essay▾

Role of carotenoids in plants.

Explanation

Role of Carotenoids in Plants

  • There are different pigments present in the plant like chlorophyll and carotenoid etc.
  • Carotenoids are red, yellow and orange pigments found in chromoplast in plants.
  • It is precursor of vitamin A.
  • Pigment help to accomplish the fruit ripening. Green-to-red.
  • The red colour is due to lycopene. Not in all cases the change in f

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Question 353

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Appeared in Year: 2017

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Short Answer▾

Explain the pigments observed in Rhodophyceae.

Question 354

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Appeared in Year: 2017

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Describe Algal Phylogeny.

Explanation

Algal Phylogeny

  • The term phylogeny is the evolutionary development and diversification of species or any particular feature.
  • The algae are an assemblage of morphologically diverse, photosynthetic Protists that are ubiquitous in distribution.
  • To understand algal phylogeny, it has been revolutionized with molecular evolutionary methods.
  • The molecular phy

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Question 355

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Appeared in Year: 2017

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Short Answer▾

Discuss the role of amphibious plants in the evolution of land plants.

Question 356

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Appeared in Year: 2017

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Discuss the different level of biodiversity. Comment briefly on in situ and ex-situ conservation of biodiversity. State the role of Cryopreservation in the conservation of plant biodiversity.

Explanation

Biodiversity

The variability among living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part, this includes diversity within species, between species and of ecosystems.

Levels of Biodiversity

It is considered that the biodiversity exist in Three level-

Generic Div

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