Asexual Reproduction

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Asexual Reproduction

• Pg 364-367

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Introduction

• Mitosis is the basis for reproduction by one
  parent ? asexual reproduction
• Common in microorganisms, plants, fungi, and some
  animals
• All offspring identical to parents (including
  DNA) and each other ?called clones

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Budding and Binary Fission

• Budding offspring begins as growth (bud) on
  parent
• When it can survive on its own, the bud detaches
• Unequal division of parent organism
• Eg yeast, hydra

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? Yeast
Hydra ?
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Binary Fission

• Organism divides into two equal cells
• Parent is lost in the process
• DNA copied, cells divide
• What process is this similar to?
• Eg bacteria and protists

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Asexual reproduction by binary fission
New individuals (Paramecium)
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Amoeba binary fission
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• A single bacteria cell can reproduce every 20
  minutes
• Over a 12 hour period a single bacterium can
  produce
• 10 million copies of itself

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Which of the following is Budding?
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Which of the following is Binary Fission?
DRAW THE ANSWERS !!
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Fragmentation

• Fragments of the parent break off and grow into
  new individuals
• Can occur by accident or purposely
• Eg planaria

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Regeneration

• Re-growing a lost body part or limb
• Usually occurs only if central part of body is
  intact
• Eg salamanders, starfish, crabs

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Spore formation

• Parent produces spores, which often have
  protective covering
• When conditions are good, they develop into new
  organism
• Eg plants, algae

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Asexual reproduction in plants
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Grafting

• Used to propagate a desired variety of shrub or
  tree
• Take a scion (twig) and insert into stock (cut
  stump)
• Eg all apple trees

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Vegetative reproduction

• Runners plant sends out aboveground stems
• New plant grows at end of runner
• Eg strawberry plants

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Vegetative reproduction

• Other plants produce thickened underground stems
• Rhizomes, bulbs, tubers (storage)
• Eg asparagus, tulips, ginger

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Vegetative reproduction

• Leaves can also form new plants
• Eg jade plant
• Some plants use roots for asexual repro
• Eg aspen trees, dandelions

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Outcomes of asexual repro

• Genetically identical offspring clones
• When is asexual reproduction beneficial?
• -when a organism must reproduce quickly
• -when the environment is unchanging
• -when a mate is hard to find
• What happens when the environment is not
  predictable?

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Homework

• Review 16.2 1-7
• Read pages 367-372tomorrows topic