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Reproductive modes

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Budding = asexual reproduction in which outgrowth becomes a new ... Parthenogenesis = development of an egg into new individual without fertilization ... – PowerPoint PPT presentation

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Title: Reproductive modes


1
Reproductive modes in animals
  • Reproductive modes
  • Two general reproductive modes in animals
  • Asexual
  • Production of genetically identical daughter
    cells from a single parent (by mitosis)
  • Daughter cells differentiate and develop into new
    individual
  • Sexual
  • Production of genetically unique gametes (by
    meiosis)
  • isogamous , - mating types produce same-sized
    gametes
  • anisogamous males and females produce
    different-sized gametes (egg and sperm)
  • Zygote formed by union of two gametes (syngamy)
  • Zygote undergoes mitosis and cells differentiate
    to develop into new individual

How are new organisms produced?
2
Reproductive modes in animals
  • Reproductive modes
  • Asexual reproduction
  • Budding asexual reproduction in which outgrowth
    becomes a new
  • Common in Phylum Cnidaria (e.g. Hydra)

How are new organisms produced?
3
Reproductive modes in animals
  • Asexual reproduction
  • Parthenogenesis development of an egg into new
    individual without fertilization
  • Sonoran spotted whiptail lizard
  • unisexual, all-female species that breeds by
    parthenogenesis
  • ovulation stimulated by "pseudocourtship" among
    the females
  • unfertilized eggs produce hatchlings genetically
    identical to mothers

How are new organisms produced?
4
Reproductive modes in animals
  • Asexual reproduction
  • Variations of parthenogenesis
  • Honeybees
  • Queen mates and stores sperm in spermatheca she
    controls use of sperm when producing offspring
  • males (drones) develop from unfertilized eggs
    (parthenogenesis)
  • females (workers) develop from fertilized eggs
    (sexual reproduction)

How are new organisms produced?
5
Reproductive modes in animals
  • Asexual reproduction
  • Variations of parthenogenesis
  • Daphnia (Water fleas)
  • Freshwater crustaceans (Phylum Arthropoda) that
    feed on algae
  • Cyclical parthenogensis alternate between sexual
    reproduction (during periods of stress) and
    asexual reproduction

How are new organisms produced?
6
Reproductive modes in animals
  • Reproductive modes in animals
  • Variation of sexual reproduction
  • Simultaneous hermaphroditism single individual
    has both male and female reproductive structures
  • Tapeworms self-fertilization
  • Earthworms during sexual reproduction each worm
    acts as male and female

How are new organisms produced?
7
Reproductive modes in animals
  • Reproductive modes in animals
  • Variation of sexual reproduction
  • Sequential hermaphroditism single individual
    changes sex during lifetime
  • Protogyny change from female to male
  • Protoandry change from male to female

How are new organisms produced?
8
Reproductive modes in animals
  • Reproductive modes in animals
  • Methods of fertilization
  • External fertilization fertilization of egg
    outside of female body
  • Broadcast spawning of marine invertebrates such
    as clams
  • Many fish and amphibians
  • Internal fertilization fertilization of egg
    within female body
  • Birds, mammals, some fish, reptiles, amphibians

How are new organisms produced?
9
Reproductive modes in animals
  • Reproductive modes in animals
  • Development modes after fertilization
  • Oviparity eggs fertilized internally but
    develop outside mothers body
  • birds, some reptiles (e.g. turtles), most bony
    fish (e.g. sunfish), most insects (e.g.
    butterflies)
  • Viviparity eggs fertilized internally and
    develop internally, relying on nutrition from
    females blood
  • mammals and many cartilaginous fish (e.g. sharks)
  • Ovoviviparity fertilized eggs retained within
    mother and develop internally, relying on yolk
    for nutrition
  • Some bony fish (e.g. guppies), many reptiles
    (e.g. garter snakes)

How are new organisms produced?
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