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REPRODUCTION

REPRODUCTION. What is reproduction ?. It is the biological process by which new individual organisms are produced . It ensures the perpetuation of the species . PROGENITORS DESCENDANTS. TYPES OF REPRODUCTION. Sexual:

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REPRODUCTION

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  1. REPRODUCTION

  2. Whatisreproduction? • Itisthebiologicalprocessbywhich new individual organisms are produced. • Itensurestheperpetuation of thespecies. • PROGENITORS • DESCENDANTS

  3. TYPES OF REPRODUCTION • Sexual: • Itrequirestwoparents: male and female. • Thedescendentshave a combination of genetic material frombothparents. • Multicellularorganisms. • Asexual: • Itrequiresonlyoneparent. • It produces new identicaldescendents. • Fungi, algae, protozoa, someplants and animals, bacteria

  4. Asexual reproduction in animals • Itiscommon in unicellularorganisms. • Types: • Gemmation: (budding), a budonparent’sbody • Fragmentation: a new organismgrowfrom a parentbody

  5. SEXUAL REPRODUCTION • Itrequiestwomembers of theopposite sex: MALE (♂) AND FEMALE (♀). • Reproductiveorgans: gonads: • Testicles (♂),and ovaires (♀) • Reproductivecells: gametes: • Spermatozoon (spermatozoa) and ovm (ova)

  6. HUMAN GAMETES

  7. Unisexual and hermaphrodites • Unisexual organisms : Each individual has onlyone tupe of gonad. • Hermaphroditeorganisms: each individual has bothgonads. • Someanimals can reproduce bothsexually and asexually: Jellyfish (polyp and medusa phase)

  8. Jellyfishcycle

  9. FERTILISATION • Itistheunion of anovum and a spermatozoon. Theyform a zygote. • Types: • External: Theunion of gametesoccursoutsidethefemale’sbody. Aquaticanimals, amphibians and someinsects. • Internal: Thefusion of thegametesoccursinsidethebody of thefemaleorhermaphrodite. Itinvolvescopulation. Terrestrialanimals and somefish.

  10. EMBRYONIC DEVELOPMENT Itincluidestheprocessesfromtheformation of thezygotetothebirth of the new individual. Thezygoteundergoesmanychanges and becomes a multicellularorganismcalledembryo. Dependingonwhereembryonicdevelopmenttakes place: • VIVIPAROUS • OVIPAROUS • OVOVIVIPAROUS

  11. VIVIPAROUS • Theembryodevelopsinside of thefemalebodywhereitrecievesnourishment and protection. Itgrows in theuterusfeedbythe placenta throughthe umbilical cord. • Itendswithbirth. Typicalfrommammalswithpacenta, fish, reptiles and amphibianswith placenta –likestuctures.

  12. HUMAN PLACENTA

  13. OVIPAROUS • Theembryodevelopsinsideanegg, normallyoutsidethefemale’sbody. Mostparentsincubatetheegg. Itfinisheswhentheegghatches. Typical of birds, reptiles and fish.

  14. EGG

  15. OVOVIVIPAROUS • Theembryodevelopsinsideaneggwhichremainsinsidethefemale’sbodyuntilithatches. Typical of somesharks, snakes and lizards.

  16. ASEXUAL REPRODUCTION IN PLANTS • Itoccurswhenplantsform new individualsfromthecells of a single parent. Types: • Sporeformation: Thenucleus of a parentcell divides into a number of daughtercellscalledspores. Sporesbecome new individuals. • Vegetativereproduction: Plantcreate new individualsfrom a particular organ.

  17. VEGETATIVE REPRODUCTION • Stolons: aerialstemswithrootswhentheytouchtheground and produce new stems. Strawberries • Fragmentation- spread and establishment of ramet by various plant parts, such as excised leaves or stems • Bulbs: undergroudstems: onions and tulips. • Stemtubers: undergroundstemswithbuds. Potatoes

  18. SEXUAL REPRODUCTION IN PLANTS • Itistypical of plantswithseeds. • Production of gametes. • Pollination • Fertilisation • Formation of embryos and seeds.

  19. FORMATION OF GAMETES: THE FLOWER • Flowerstructure: • Calyx: greensepals. Protection • Corolla: colouredpetals. Toattractinsects. • Stamen: maleorgan. Filament and antherscontainigpollen. • Pistil: femaleorgan. Carpelscontainingovaries, style and stigma.

  20. THE FLOWER

  21. FERTILISATION AND SEEDS • Thepollengrainslandonthepistil. Thepollentubesreachtheovary . Bothnucleus fuse and formthezygote. Itgrowsintoanembryo. • Theripened ovule becomes a seedthatcontainstheembryo and foodstored in theendosperm. Itslowlybecomes a fruit.

  22. SEED GERMINATION • Theembryodevelopsinto a new plant. Theembryo can containoneortwoleaveswithfoodcalledcotyledons.

  23. GERMINATION

  24. TYPES OF SEEDS

  25. SUMMARY • FLOWER • POLLENOVULE fertilisation EMBRYO formation of seeds SEED germination FRUIT NEW PLANT

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