Reproduction process and types of the asexual reproduction
The reproduction process importance
The genetic traits pass from the parents to offspring by the reproduction process which is a biological process , where the living organisms produces new individuals of the same kind and thus , ensuring its continuity .
The reproduction process produces new individuals of the same kind and preserve it from extinction , There are two types of reproduction which are the asexual reproduction and the sexual reproduction .
The asexual reproduction
The asexual reproduction occurs by only one living organism , It mostly occurs in single-celled living organisms ( such as yeast and Amoeba ) , It is the process by which the living organism produce new individuals with genetic traits identical to those of their parents .
The asexual reproduction occurs in unicellular living organisms , some multicellular animals and plants , It takes place by mitosis division which does not require special systems or structures in the living organism .
The types of the asexual reproduction are Binary fission , Budding , Regeneration , Spore propagation and Vegetation reproduction .
The asexual reproduction in the living organisms produces individuals ( offspring ) identical in the genetic structure of the original organism , The similarity in genetic structure is caused by mitosis .
The new offspring gets a full copy of the parent individual’s genetic traits , if the number of chromosomes in the parental cell ( 2 N ) , the number of chromosomes in the offspring is ( 2 N ) , So , no genetic variation occurred causing difference in the resulting offspring than the original organism .
Binary fission occurs in unicellular organisms as unicellular protozoans ( Amoeba , paramecium , Euglena ) , Simple algae and bacteria .
How does the reproduction by binary fission occur ?
The nucleus divides by mitosis division and the cell splits into two cells , Each cell grows and becomes a new individual , Each is identical to the original cell .
The cells that are resulted by binary fission are identical and similar to the parental cell , because they are resulted by the mitotic division .
The reproduction by budding is a asexual reproduction that produces new individuals by formation of buds in the parent cell , Budding occurs in unicellular organisms ( as yeast fungus ) , Multicellular organisms ( as Hydra and Sponges ) .
How does the reproduction by budding occur in yeast fungus ?
The bud emerges as a lateral bulge in the cell , The cell nucleus divides mitoticaly into 2 nuclei , one of them remains in the parent cell and the other migrates to the bud .
The bud grows gradually and remains connected to the parent cell until it is fully grown , then it separates from it , If the buds remain connected to the parental cell , colony is formed .
The regeneration is the animals ability to compensate their missing parts , The living organism can reproduce by one of its parts , It occurs in some animals ( such as the starfish ) .
The starfish arms could be regenerated and give out a complete animal if they contain a part of the central disc of the animal .
If the chromosome number in the cells of starfish is ( 2N ) , the number of chromosomes in the cells resulted by regeneration is ( 2 N ) , too , because regeneration is asexual reproduction that occurs by mitosis division .
Sporogony ( Spore propagation )
Sporogony occurs in some fungi such as bread mould and mushrooms , some algae , where each sporangium rupture and a large number of spores are released , when the spores are scattered on a suitable environment , they grow to give new organisms ( fungi ) .
The vegetative reproduction occurs without the need of seeds but by the plants vegetative organs ( the leaves , the roots and the stems ) in order to produce new plants identical to the parent plant .
The vegetative reproduction also occurs by the plant cells in the tissue culturing , the vegetative propagation in plants includes the mitotic division of the cell , The vegetative reproduction is an asexual reproduction by using the vegetative organs except the seeds .