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Asexual Reproduction

Teacher/Instructor Patrick Roisen
Patrick Roisen

M.Ed., Stanford University
Winner of multiple teaching awards

Patrick has been teaching AP Biology for 14 years and is the winner of multiple teaching awards.

Asexual reproduction is a type of reproduction found mostly in prokaryotes. Asexual reproduction doesn t require fertilization and only one parent cell is needed to reproduce. In achaea and bacteria, the type of cell division that is involved in asexual reproduction is known as binary fission.

A lot of creatures on this planet undergo a process known as asexual reproduction. What this is is basically when a new cell being produced by an asexual reproducer winds up looking exactly like its parents all because it has the same DNA.

Now there's a lot of advantages to this. It's fast and it's actually pretty easy. I mean compare that to what we have to go through with sexual reproduction. you would never have to think about who am I going to act act ask out for prom? Are they going to reject me? And I know exactly what I want for my anniversary. It's awesome. It's also efficient if suited to the environment. If I've got a great set of DNA, and it allows me to do really well in this environment then if I clone myself which is what asexual reproduction is, then my clone will be just as well suited as I am. If I do sexual reproduction then I'm mixing my DNA with somebody else's. And who knows? Maybe that person's combination of DNA is not as great as mine or perhaps it is but unfortunately when we now create a new mix, that new mix may not work out so well and you may be aware of this if you've ever paid attention to the fact that the number of pregnancies end in miscarriage. That's just because of poor combinations of DNA.

So it is really efficient if suited to the environment because one parent can produce one child who's a hundred percent the same DNA and you can just do that whereas right now with sexual reproduction, each one of my kids is only half of my DNA. So for me to completely replace myself I have to have two children. that's exhausting and expensive.

The disadvantage the asexual reproduction however, is that you wind up having problems if the environment does change because since every child every offspring is identical to the parent, only when mutations creep in can you get any genetic change to allow you to survive and adapt to these new changes in the environment. That's why most multicellular creatures have adapted to doing sexual reproduction. That's the only way that we're able to stay ahead of the asexually reproducing bacteria because one of their generations that's 20 minutes. One of our generations 20 to 30 years. So we need to do sexual reproduction in order to have the quick rapid genetic change to stay ahead of the bacteria and viruses.

Now at the cellular level, there's two processes that allow for asexual reproduction. One is binary fusion done by the prokaryots. The other is mitosis done by the eukaryots. At the organism level there's many diffrent kinds of asexual reproduction. Some examples include budding. If you ever see a one of the ways that we can reproduce is that they can grow little new one off of them. I've seen a time lapse photography that showed it going like this and then it just slowly separated into two new clone.

Fragmentation. There are some creatures that can survive being broken off. I discovered when I was a younger person my dad kept making me weed in the back yard, they had a lot of plants that can grow through fragmentation. If you rip up a weed just rip off the top part, the bottom part can start to create new weeds from that. I discovered this also when one of my neighbors cut down his tree but I didn't realize there was a bunch of his tree roots underneath my back yard until all of a sudden a bunch of trees started sprouting up from my lawn. I had to rip up my lawn to deal with his massively asexual reproducing tree.

And a weird one is called something called pathonogenesis and that's where a egg is laid but does not require any fertilization by a male, yet it can give rise to completely mature new adult. There are some lizards I've read about which can hop from one island to the next if they occasionally get caught caught in a storm or in a piece of vegetation and because they can do this pathonogenesis that one lizard, if it lands on an unoccupied island, that's not occupied by other lizards, It can soon branch off and form a whole new colony from just that one lizard, does have problems with lice though and other mites that can attack it because since it can't quickly adapt it soons falls prey to parasites.

So, that's asexual reproduction.