REPRODUCTION

REPRODUCTION

1. Asexual

   • creation of new individual without fusion of gametes
   • no production of gametes except parthenogenesis
     • only eggs
   • rely on mitotic division
   • all genes come from 1 parent
   • rapidly produce offspring
     • genetically identical unless mutation
   • vegetative propagation (plant)
     • stolon
       • horizontal stem on ground
       • can produce new clone from buds at intervals
       • strawberry
     • bulb
       • short underground stem to which overlapping
       • onion
     • rhizome
       • horizontal underground stem
       • ginger
       • new aerial shoot arise from axillary buds on the rhizome
     • tuber
       • swollen underground stem store food
         • root
         • stem
       • potato
     • corm
       • very short & erect underground stem
       • water chestnut
     • leaf
       • leaf margin produce plantlets
       • bryophyllum
     • sucker
       • root produce new plant
       • banana
   • in animal
     • parthenogenesis(virgin birth)
       • egg develop into young without fertelised
       • komodo dragon
       • aphids
         • use when food is ample to exploit the food
     • budding
       • formation bud fom parent cell
       • grows, detaches & germinates
       • yeast
     • binary fission
       • unicellular divides into 2
       • receive DNA, ribosomes & cytoplasm
       • amoeba
     • regeneration
       • parent body breaks, each grow into organism
       • starfish

2. sexual

   • fusion of sperm & oocytes
   • genetically different
   • trasnfer RNA & DNA to progeny
   • involves gametogenesis & feterlization
     • gametogenesis= formation of gametes
     • internal
       • copulation
         • male delivers sperm directly into female
       • fusion inside
       • terrestrial org
       • devp. of embryos
         • oviparity
           • fertelize-inside, devp.-outside
           • animal lays eggs
           • chicken
         • viviparty
           • devp. occur inside
           • gain nutrient directly from mother
           • retained in uterus for a period
           • tiger
         • ovoviparity
           • devp. inside shelled eggs in mother's body
           • matured, hatched & released
           • embryo obtain nutrient (eggyolk)
           • shark
     • external
       • aquatic org
         • frog fish
       • fusion outside body
       • mating partners release gamete simultaneously
       • short lifetime/many released
   • permit recombination of DNA (adv)
   • enhances survival

3. new species formed & genetic material are passed down to next generation