Information about the methods of Asexual reproduction
Asexual reproduction needs only one parent, unlike sexual
reproduction, which needs two parents. Since there is only one parent, there is no fusion of gametes and no mixing of genetic information. As a result, the offspring are genetically identical to the parent and to each other. They are clones. This saves time, especially when you consider seasons, generally animals and plants only reproduce in late spring and early summer, this allows the offspring to feed on the abundance of life which is associated with summer. As Autumn and winter sets in, the food supply dwindles and becomes difficult to find.
A sexual reproduction also allows for a greater number of offspring to be produced, however the main issue with asexual reproduction is all offspring are genetically identical, that is they share the same genetic information, which makes it difficult to adjust to changes in climate or disease. In essence, if one animal or plant is affected by disease, then all its offspring will also be just as susseptable to disease as well. Genetic variability which is found in many animals and plants including humans means that each offspring is different, so each one is more likely to survive disease since they are gentically unique.
Asexual reproduction is advantageous in allowing beneficial combinations of characteristics to continue unchanged and in eliminating the often vulnerable stages of early embryonic growth. It is found in most plants, bacteria, and protists and the lower invertebrates. In one-celled organisms it most commonly takes the form of fission, or mitosis, the division of one individual into two new and identical individuals. The cells thus formed may remain clustered
together to form filaments (as in many fungi) or colonies (groups)
Fragmentation is the process in which a piece of the parent breaks off and develops into a new individual.
Asexual reproduction in plants can take a number of forms. Many plants develop underground food storage organs that later develop into the following year's plants. Potato plants and daffodil plants do this, for example. Some plants produce side branches with plantlets on them. The spider plant, Chlorophytum does this. Other plants, such as strawberries, produce runners with plantlets on them.
Asexual reproduction in animals does occur - it happens in sea anemones, starfish, for example - but it is less common than sexual reproduction.
Some animals also use both sexual and A sexual reproduction, these are commonly insects such as Aphids and Bees, however some lizards including Comodo Dragons and Whiptail Lizards can reproduce using both methods, this is called Parthenogenesis which is covered in more detail later.
Click the picture to find out more about partheonogentic reproduction
There are many different types of A sexual reproduction that both plants and animals use. What is important to remember is 'Primary Function', that is to say the main reason for any plant or animal to exisit, the anmser is simply to reproduce.
Humans have evolved over a few million years, and if you take time to review human reproduction, you will quickly understand that it is not very efficient. Think about it, for humans to reproduce there needs to be both a make and a female invovled in the process, generally once fertalisation has taken place, the number of offspring produced is low, usually 1 to 3. The whole process is time consuming, about 9 months, and in this time the female cannot become pregnant again.
Many would view this process as fortunate for the plant, as currently humans populate just about every corner of the globe, we are using up natrual resources at an alarming rate, and as we continue to reproduce the situation will only get worse.
No other organism reproduces to this extent, all other organisms are controlled by avaiable resources such as food and space.
Below are a number of different A sexual methods of reproduction.
Click on the pictures to find out more about each method.