Basically, asexual reproduction is a type of reproduction which involves simple division of the organism with the help of a single parent with or without the involvement of gamete formation. This type of reproduction is generally found in single-celled organisms. As a result, a single parent split into two daughter cells that have their own identity. The offspring organisms are physically and genetically identical to their parent cell or we can say a carbon copy. Asexual reproduction is the main type of reproduction found in single-celled organisms. However, asexual reproduction is less commonly found in the animal kingdoms. Also, asexual reproduction is commonly seen in living things and takes a variety of forms. There are rapid multiplications and growth seen in a small period of time but sometimes some of the asexual cells die when they are very young. It has been seen that the asexual reproduction animals are generally found in freshwater than in the oceans. Such type of reproduction is more prominent in small species and is not so popular in large species. It has been seen that asexually reproducing species are more commonly present in polar areas and temperate regions as compared to the tropical regions.

The different modes of asexual reproduction in animals are Binary Fusion, Fragmentation, Budding, Parthenogenesis, Gemmules, and Regeneration. Some examples are explained below that help in understanding the concept in a better way.

Features of Asexual Reproduction

In asexual reproduction, only one parent is involved.
The process of this reproduction is instant as compared to sexual reproduction.
There is no involvement of gamete formation and fertilization.
Offspring growth is rapid in asexual reproduction.
There is no variation in this reproduction, as offspring organisms are carbon copies of their parents.

Some of the Examples of Asexual Reproduction in Animals

There are various examples of asexual reproduction in animals that provide a better understanding of the topic.

Bacteria – In bacteria, asexual reproduction happens by splitting into two ‘daughter’ cells that are genetically identical to their parents. In this, the genetic material is passed ‘horizontally’ from one organism to another instead of ‘vertically’ from parent to the child. This involves very fast reproduction and that is the only reason why the bacteria are so quick to develop antibiotic resistance.
New Mexico Whiptail Lizards – All New Mexico whiptail lizards are females and are capable of reproducing an independent population. This species of lizard was created by the hybridization of two neighboring species.

Types of Asexual Reproduction

Here, we are going to discuss some types of asexual reproduction seen in animals.

Binary Fusion – Bacteria and amoeba are the main organisms in which this method of reproduction is seen. In this, the DNA of the parent bacteria replicates itself and gets divided into two parts where each part has its own DNA. Hence, the parent cell divides into two identical daughter cells and these cells are identical to the parent cell.

i) Simple Binary Fission – It can occur at any place. For instance- Amoeba

ii) Longitude Binary Fission – It occurs in Flagellates such as Euglena.

iii) Transverse Binary Fission – The main example of this binary fission is Paramecium, Planaria, Diatoms, and bacteria.

iv) Oblique Binary Fission – It occurs in Cerium.

Fragmentation - In this type of method of asexual reproduction, the parent organism is divided into multiple segments and each of the fragments develops into a new organism. One of the most common examples of this mode of asexual reproduction is Starfish. Any part of its body such as the arm can give rise to an entirely new organism.
Budding – In this mode of reproduction, the offspring develops on the body of the parent just like a bud. Echinodermata and hydra are common examples of this type of asexual reproduction. Here, the bud falls of the parent body and starts its own independent existence.

i) Exogenous/ External Budding - In this kind of budding, a bud grows on the surface of the body. This growing bud splits away from the parent and takes an independent existence. The newly grown bud may remain attached to the parent or would become a parent itself and create independent members.

ii) Endogenous/ Internal Budding – A few marine sponges buds are formed within the parent’s body in freshwater sponges (e.g. Spongilla).

iii) Strobilation –The repeated formation of similar segments with the help of the budding process is called strobilation. Partitioned part of the body is called a strobila (i.e. scyphistoma) larva and each segment is called an ephyra larva as found in Aurelia (a coelenterate).

Parthenogenesis – In this type of asexual reproduction, the female organism produces eggs without fertilization, and offspring are created. Lizards, some fishes, and insects are the common examples of Parthenogenesis asexual reproduction.
Gemmules – In this type, the parents release a specialized mass of cells that develop into offspring. These gemmules can be formed at a time when parents feel harsh environmental conditions around them.
Regeneration – It is the formation of the whole body of an organism from the small segment (morphallaxis) or the replacement of the lost part (epimorphosis). It is mainly found in amoeba, hydra, sponge, planaria, and many more organisms.

i) Reparative Regeneration – In this, only certain damaged tissues can be regenerated.

ii) Restorative Regeneration – In this, severed body parts can be redeveloped or developed into a complete body.

Advantages of Asexual reproduction

With the help of asexual reproduction, population increases rapidly. It is especially useful for species whose survival strategy is to reproduce at a fast pace. One of the common examples is bacteria.
In asexual reproduction, species find their members themselves like fungi that grow from wind-blown spores.
Asexual reproduction is often accomplished by just having a part of the parent organism.
This reproduction is friendly to the environment. It has no concerns with regard to environmental impact. Moreover, there are no risks which can cause any type of problem to the other partner.
There is no need of energy and time to produce offspring. Also, it does not require any true investment.
Asexual animals have the ability to keep themselves alive and continue to produce offspring even during emergencies. They do not require any reproductive sources to produce cells.
In asexual reproduction, the organism does not require different places to produce its offspring. It just requires a single place and does not involve moving around to see the process taking place.

Disadvantages of Asexual Reproduction

In this form of reproduction, there is no control over the rapid increase of the population. It doubles its population in each of the reproductive cycles. However, scientists have found that the process would stop only where the total number of organisms becomes excessive at a certain point.
This kind of reproduction can create competition because some of the organisms are in close relation with each other.
Asexual reproduction can result in overcrowding which may be an issue. One parent can produce a high number of offspring in a very less period. Overcrowding causes a lack of resources that could stop the organism from future growth.
It is always not possible to adapt to a new environment for asexual reproduction. The inhabitant could destroy the entire species in a very short duration of time.
It may sometimes lead to unfavorable conditions like extreme temperatures that can eliminate the entire community.

With the help of the advantages and disadvantages of asexual reproduction, it will be much easier for us to take care of the organisms around us.

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FAQs on Asexual Reproduction in Animals

1. What is the process of Binary Fission and what are its drawbacks?

The type of asexual reproduction in which, an organism splits itself into 2, with each part holding 1 copy of genetic material is called Binary Fission. This kind of asexual reproduction is generally observed in prokaryotes and single-celled eukaryotes. In Binary Fission, there is a separation of the parent cell into 2 new daughter cells and this process occurs with the division and replication of the parent’s genetic matter into 2 parts. This type of asexual reproduction happens without any spindle apparatus formation in the cell. During binary fission, the single DNA molecule starts the process of replication. It then connects each copy to different parts of the cell membrane. When the cell begins to separate, the original and duplicated chromosomes get separated.

There are some drawbacks of binary fission. As a type of Asexual form of reproduction, all resulting cells are genetically identical and identical copies of one another and the parent cell. The concept of antibiotics works on this principle. If a parent cell is vulnerable to a particular antibiotic, then all produced daughter cells, formed by splitting become vulnerable too. This reduces the survival chances of organisms with this type of reproduction. In case of a mutation in their genes, the cells can generate a particular strain immune to those antibiotics.

2. What is the process of fragmentation in plants?

Fragmentation is a common type of asexual reproduction in plants. It is a kind of Vegetative Reproduction in plants. Fragmentation happens when a shoot that is rooted evolves and detaches from the main group. Plants have different mechanisms known as mechanisms of natural fragmentation in plants. One such is Specialized Structures. Few plants exist that could form adventitious plantlets on their leaves. This would later separate to create individually grown plants. Some other types of plants produce different organs like turions and bulbils.

The procedure of fragmentation is a common phenomenon in some nonvascular plants such as liverworts and mosses. In the case of moss leaves or stems, they are carried by the wind, animals, or even water. Once the moss fragment gets a desirable environment, it roots itself to form a new plant. Fragmentation is also used artificially for various purposes. It can be used to reproduce by cutting, layering, grafting, and division.

3. What is Natural Vegitative Propagation?

Vegetative Propagation happens when the plant grows and develops naturally without any mortal interference. The development of adventitious roots is commenced by Natural Vegetative Propagation. The new plants might emerge from the roots, stems, or leaves of their parent plant. The vegetative plant structures arising from the stem are known as bulbs, runners, etc. Some of the plants propagated vegetatively are given below:

Stems- With stems, runners rise horizontally above the ground, and buds are developed at the nodes of the runners.
Roots- With roots, new plants appear out of swollen, modified roots known as tubers and the buds are formed at the base of the stem.
Leaves- Leaves of some plants get separated from the parent plant and grow into a new plant.
Bulbs- There's an underground stem in bulbs to which the leaves are connected. These leaves are capable of keeping food and the center of the bulb consists of an apical bud that creates leaves and flowers. Shoots are planted from the use of the lateral buds.

4. What is External Fertilization in Animals?

Fertilization is the process of fusion of the male sperm with the female ovum to produce a zygote. Fertilization is the first and very important phase of sexual reproduction. In sexual intercourse, the penis of a male ejaculates millions of sperms into the vagina of a woman. Sperms travel via the uterus to reach the oviducts. At the oviduct, 1 out of those million sperm fertilizes the released ovum and the fertilized egg evolves into a zygote. If this fusion of sperm and ovum occurs outside the female body, it is called External Fertilization. Very few organisms show this type of external gamete fusion. In External Fertilization, the female parent deposits her eggs in one place. Later, the male parent ejects his sperm over those eggs and this starts the process of fusion. Gametes that fuse externally face many challenges since eggs and sperms are deposited in the external environment. The chances of fusion in external fertilization are very less because the predators might eat eggs or the zygote that is formed. Organisms like frogs lay hundreds of eggs together at a time to improve the odds of reproduction.

5. What is Sporogenesis in plants?

Sporogenesis is a type of asexual reproduction where the formation of spores is observed. Asexual Reproduction through spores involves the spread of the spores by water or air. The formation of microspores is called microsporogenesis and the formation of megaspores is called megasporogenesis. Microspores are formed in the anther of the plant and develop into pollen grains. The Megaspores are formed inside the ovule and develop into the embryo sac. Sporogenesis involves the formation and development of the spores. This process is sporogenesis in plants.