Asexual Reproduction:

1. Asexual Reproduction: It takes only one!

2. What is it and what’s it’s function? • Asexual Reproduction is: when 1 organism gives rise to 2 identical organisms ( this is essentially cloning!) • Organisms reproduce asexually when there is an abundance of food, and when other environmental conditions are very good • Asexual reproduction does not take a lot of energy in terms of raising the offspring or going through mating rituals; and allows populations to grow quite large in a short amount of time.

3. There are 5 types of Asexual Reproduction: • Binary Fission • Budding • Fragmentation • Spore Formation • Vegetative Reproduction

4. Binary Fission • Virtually the same as mitosis, binary fission causes one cell to divide into 2 after all its organelles and DNA have replicated. • Binary fission takes place in single-celled organisms such as bacteria and most protists Protist: Paramecium Bacteria!

5. Budding • http://Hollenhorst and Catherine Fox • A miniature of the original parent comes off of the parent by an out pouching of cells or cytoplasm from the parent • A new organism forms eventually and breaks away from the parent • Occurs in yeast, hydra and some plants

6. Fragmentation • Pieces from the parent break off and form a new organism identical to the original parent • Occurs in planaria (a free-living flatworm) and sea stars. • Often fragments of these seastars must include part of the middle disc to create a new organism. • Regeneration typical in sea stars, demonstrates a similar mechanism – in the photo here only one arm is being recreated.

7. Spore Formation • When a bacterial cell senses harmful or inhospitable conditions, this vegetative cell replicates its DNA and its cell wall begins to surround the new DNA copy. A durable spore coat forms around the developing spore and eventually will await better conditions for growth. • Occurs in bacteria (endospores), some protists, fungi, ferns and mosses.

8. Vegetative Propagation • Stolons travel above ground and land in another viable place where soil is good enough that another crown and root system can be made • Occurs in strawberry plants, spider plants, grasses, lilacs, and ferns.

9. What are the benefits to reproducing asexually? • You don’t need a partner! • You can reproduce faster in good conditions • You use less energy • You increase the population of your species • You can make an exact replica of yourself (for those of you who are vain!) and thus know exactly what the offspring will be. * Farmers use seeds that are genetically identical when they plant their crops….. How does this benefit them?

10. What are the costs or disadvantages to reproducing asexually? • There is no exchange of genetic information and so no genetic variation will exist in the population – evolution of a species may not occur • Usually occurs only when environmental conditions are good. • Organisms that have developed from asexual reproduction are prone to diseases and viruses or other environmental problems because of a lack of variability in the genetic make-up of the population

11. ___ Yeast ___ Bacteria ___ Strawberries ___ Planaria ___ Hydra 1. Spore Formation 2. Vegetative Reproduction 3. Binary Fission 4. Budding 5. Fragmentation Matching: Which organism would use which type of asexual reproduction? Ans: Yeast – 1 & 4; Bacteria – 1 & 3; Strawberries – 2; Planaria – 5; Hydra – 4

12. Bibliography and Credits • http://sciences.aum.edu/bi/BI2033/thomson/binaryfission.html • http://biology.about.com/library/weekly/aa090700a.htm • http://biology.about.com/gi/dynamic/offsite.htm?site • http://www.cs.tufts.edu/%7Ecabotsch/bulloughs/invertebrates/worms/flatworm.html • http://plantphys.info/Plants_Human/vegprop/vegpropn.html • http://www.microbe.org/microbes/spores.asp