(REP) Asexual Reproduction Lesson

Asexual Reproduction Lesson

Asexual reproduction is the production of offspring by a single parent, without sperm or egg. Therefore, DNA comes from a single parent. The offspring are normally identical because its chromosomes duplicate themselves and divide so that each offspring (daughter) cell has a full set of chromosomes that are identical to the original (mother) cell. Many plants, bacteria, and single-celled organisms can reproduce asexually. Tulip bulbs, corn, potato plants, and strawberry plants can produce new plants by asexual reproduction. The new plants can grow from a piece of the stem from a parent plant.

Yeast is a single-celled eukaryotic organism that belongs to the kingdom Fungi. Yeast cells can reproduce by budding. An outgrowth or bud of the parent cell breaks off to form a new organism that can survive on its own. Fungi can also reproduce by releasing spores from their reproductive structures called fruiting bodies. Millions of spores can be released from a fungus. The spores have a protective covering that helps them travel through water and air. Fungi are capable of reproducing sexually. The fruiting bodies of some fungi are tiny stalk-like extensions called hyphae. When the hyphae of two different fungi connect, genetic information is exchanged and a new reproductive structure (hyphae) develops to release spores into the environment.   The new spores are genetically different from both parents.  

Sponges are invertebrate animals that can reproduce asexual by budding too. Some species of worms can reproduce asexual by a process called fragmentation. If a worm is cut in half, a whole new worm can grow from each of the pieces.  

Binary fission is the term used to describe the asexual reproduction in bacterium. During binary fission, one cell duplicates its genetic information before it divides into two identical cells. Each new cell has the same genetic information as the parent cell.

The most common type of reproduction in protists is binary fission. Paramecia are animal-like protists that reproduce asexually by binary fission. Some unicellular protists can reproduce by fragmentation. The fungus-like protists reproduce by dispersing spores that can later grow into a new organism.

Sometimes some species of bacteria, protozoans, fungi, and algae can reproduce sexually by using a process called conjugation.   During conjugation in bacteria, a threadlike bridge connects two bacteria together. Genetic information is transferred from one bacterium to another bacterium. After the bacterial cells separate, the bacterium has a new combination of genetic material.   The new bacterium is genetically different from the original bacterium. Conjugation increases the genetic variation within a species of organisms.

 

Advantages and Disadvantages of Asexual Reproduction

Watch the following presentation.

 

 

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