Asexual Reproduction

ASEXUAL vs. SEXUAL  Requires only one parent organism  Offspring genetically identical to parent (clones)  No specialized cells for reproduction  Requires two parent organisms  Offspring not identical to parents due to exchange of DNA  Specialized reproductive cells

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

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

 Yeast Hydra 

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

Asexual reproduction by binary fission New individuals (Paramecium)

Amoeba binary fission

A single bacteria cell can reproduce every 20 minutes Over a 12 hour period a single bacterium can produce 10 million copies of itself

Which of the following is Budding?

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

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

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

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

Asexual reproduction in plants

Vegetative reproduction  Runners: plant sends out aboveground stems  New plant grows at end of runner  Eg: strawberry plants

Vegetative reproduction  Other plants produce thickened underground stems  Rhizomes, bulbs, tubers (storage)  Eg: asparagus, tulips, ginger

Vegetative reproduction  Leaves can also form new plants  Eg: jade plant  Some plants use roots for asexual repro  Eg: aspen trees, dandelions

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?