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NAVODAYA VIDYALAYA JOGNA PK25NG

E-CONTENT FOR CLASS X SCIENCE

HOW DO ORGANISMS REPRODUCE?

Prepared by

P.KN

PGT BIOLOGY, JNV LOHARDAGA

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HOW DO ORGANISMS REPRODUCE

  • REPRODUCTION IS THE BIOLOGICAL PROCESS OF PRODUCING YOUNG ONES.
  • it enables continuity of species generation after generation.

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ASEXUAL REPRODUCTION AND SEXUAL REPRODUCTION

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ASEXUAL REPRODUCTION

  • Asexual reproduction is a form of reproduction in which an organism  gives rise to genetically-identical individuals. It involve only single parent.

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TYPES OF ASEXUAL REPRODUCTION

  • FISSION
  • FRAGMENTATION
  • BUDDING
  • VEGETATIVE PROPAGATION
  • SPORE FORMNATION

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FISSION�

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It is the process of division of a single Cell into two or more individuals

TYPES OF FISSION:

  • 1.BINARY FISSION
  • 2. MULTIPLE FISSION

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BINARY FISSION

  • Binary fission is an form of asexual reproduction by which the body splits into two new bodies.
  • Eg: AMOEBA , AND LEISHMANIA

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MULTIPLE FISSION

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  • A single cell splits into many daughter cells are produced from the parent cell.
  • Eg:Plasmodium

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FRAGMENTATION

  • Body breaks into fragments.each fragment develops into an organism+
  • Eg: Spirogyra

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REGENERATION

  • Some organisms have Ability to give rise to new individual organism from lost body parts. Eg.Planaria

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Vegetative Propagation

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  • It is a kind of asexual reproduction in Which a vegetative parts of a plant like stem, leaf and root grows into a new plantlet.
  • Vegetative propagation can occur naturally or Artificially.
  • Types of natural vegetative propagation are tubers, runner, rhizomes and bulbs.
  • Types artificial vegetative propagation are cuttings and grafting.

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Vegetative Propagation

Cuttings

  • Pieces of a root or stem that in certain conditions are made into new plants.
  • Some examples are bananas, roses and sugar cane

Grafting

  • Taking a part of a plant and connecting it to another one.
  • Combining the two plants.
  • Some examples are seedless oranges and grapes.

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SPORE FORMATION

  • Spores develop into an individual organism. Eg.Rhizopus.It develop spores like blob-on-a-stick like structures.

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  • SEXUAL REPRODUCTION IN FLOWERING PLANTS
  • Sexual Reproduction:
  • Flower produces gametes which fuse together to produce a new individual
  • Floral parts: include,sepals,petals,stamens and pistil. Stamens-anther and filament

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  • POLLINATION:

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  • Transfer of pollens to stigma.
  • Self-pollination: Pollen is transferred to a stigma of the same flower, or another flower on the same plant
  • Cross pollination: pollen reaches the stigma of a flower on a different plant (of same species)

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  • DIAGRAM OF LS OF A FLOWER

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  • DOUBLE FERTILIZATION

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  • Pollen tube grows along style and reach embryo sac.
  • One male gamete of pollen fuses with egg cell and forms zygote
  • other male gamete fuses with polar nuclei and forms endosperm
  • Embryo: The growth of a zygote results into an embryo
  • Seed: ovules- and Fruit-ovary

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GROWTH OF POLLEN TUBE

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  • DOUBLE FERTILIZATION