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Asexual Reproduction in Animals and Examples

 
By Anaƫlle Laurent. November 22, 2020
Asexual Reproduction in Animals and Examples

There are different types of reproduction in the animal kingdom, and even different modes of reproduction. However, in this AnimalWised article we're going to talk about asexual reproduction in animals.

We're going to explain the definition of asexual reproduction, its different types and we'll also give plenty of examples. Keep reading to learn more!

You may also be interested in: Types of Animal Reproduction

What is asexual reproduction?

Asexual reproduction is a type of reproduction carried out by certain animals and plants, where the fusion of gametes or change in number of chromosomes is not involved. In other words, this type of reproduction does not involve two individuals copulating. It is simply done by one individual.

It is often done by a parent cloning themselves, however there are many different types of asexual reproduction which we will take a look at later in this article. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and bacteria. Many multicellular animals, plants and fungi can also reproduce asexually.

Main characteristics

To sum up, here are the main characteristics of asexual reproduction:

  • Only one parent is involved
  • No fertilization or gamete formation takes place
  • This process of reproduction occurs in a short period of time
  • Their offspring is genetically the same or very similar

Types of asexual reproduction and examples

There are many types and subtypes of asexual reproduction in animals and, if we include plants and bacteria, the list gets even longer. So, let's take a look at the main types of asexual reproduction in animals:

Fission

Also known as binary fission, is when an organism splits into two separate organisms after a period of growth. This occurs through mitosis which is when a parent cell splits into two identical daughter cells of the same size.

This mainly occurs in prokaryotic microorganisms (archaea and bacteria) and in some invertebrates. Unicellular eukaryotic organisms (protists and fungi) may also undergo binary fission by mitosis, however, most of these are also capable of sexual reproduction.

Examples include: bacteria, fungi, algae and some parasites.

Fragmentation

In fragmentation, a body part breaks away which later develops into complete organisms. This is most known in the case of starfish that can separate an arm to asexually reproduce or in life-threatening situations. Then, that arm will completely develop into an identical starfish. However, like many other asexual reproductive animals, starfish are capable of reproducing sexually too. Learn more in our article about how starfish reproduce.

This also occurs in most lichens, which form a symbiotic relationship between a fungus and photosynthetic algae or bacteria. This ensures that new individuals contain both symbionts.

Examples include: some bacteria, some fungi, starfish, lichens, some sponges, some annelid worms and some acoel flatworms.

Asexual Reproduction in Animals and Examples - Types of asexual reproduction and examples

Budding

This type of asexual reproduction is when an organism reproduces from the outgrowth of a part of a cell or body region, leading to a separation from the original organism into two individuals. This mainly occurs in some invertebrate animals, such as corals and hydras.

To give a better understanding, let's take a look at the example of hydras. In these organisms, a bud forms that develops into an adult, which breaks away from the main body. Whereas in corals, the bud does not detach, but it multiplies as part of a new colony. Corals can also reproduce via fragmentation.

Examples include: corals, hydras, some sponges, some acoel flatworms and echinoderm larvae.

Parthenogenesis

This type of asexual reproduction is when an egg develops into a complete individual without being fertilized. The resulting offspring can be either haploid or diploid. This will depend on the process and the species. Parthenogenesis occurs in invertebrates, such as water fleas, rotifers, aphids, stick insects, some ants, wasps and even bees.

In the case of bees, these insects use parthenogenesis to produce haploid males (drones) and diploid females (workers). If an egg is fertilized, a queen bee is produced. However, only the queen bee regulates the reproduction of bees in her hive. If you want to learn more, we invite you to read our article about what bees eat.

Some vertebrate animals, such as certain reptiles or fish, also reproduce through this type of asexual reproduction. There are also plants that use this method of asexual reproduction.

Examples include: Komodo dragons, bonnet-head sharks, black-tip sharks, other reptiles, amphibians and fish, as well as water fleas, rotifers, aphids, stick insects, some ants, wasps and bees.

Hermaphroditism

Another similar occurrence when it comes to reproduction in the animal kingdom, is hermaphroditism. This is when an organism has both male and female gametes, and therefore, can reproduce sexually or asexually. This is the case for earthworms, snails, leeches, prawns, oysters, starfish, certain frogs and certain fish. Learn more in our article about hermaphroditism.

Advantages and disadvantages of asexual reproduction

Animals do not use this reproductive strategy as a habitual method of reproduction. Instead, they only carry it out at adverse times, such as changes in the environment, extreme temperatures, drought, absence of males, high predation, etc.

Asexual reproduction reduces genetic variability, which could result in the disappearance of a colony, group or population of animals if sudden changes in the environment continue. With this being said, let's take a look at the advantages and disadvantages of asexual reproduction:

Advantages

  • Mates are not required
  • The process of reproduction is fast
  • Many organisms can be produced in a short amount of time
  • Positive genetic characteristics pass onto their offsprings
  • Can occur in different environments, even harsh climates
  • Can help keep the species alive

Disadvantages

  • Lack of diversity in the genetics
  • They are unable to adapt to the changing environment
  • Negative genetic characteristics are also passed onto their offsprings
  • A single change in the environment could eliminate the entire species

This is why many of these animals opt for sexual reproduction, but if that is not possible, as it can be difficult for them to find a mate, they will resort to asexual reproduction in order to ensure themselves the continuity of their species.

Want to learn more? Watch this video about asexual reproduction in animals.

If you want to read similar articles to Asexual Reproduction in Animals and Examples, we recommend you visit our Facts about the animal kingdom category.

Bibliography
  • Álvarez-Romero, J., RA Medellín, H. Gómez de Silva and A. Oliveras de Ita. 2005. Ramphotyphlops braminus. Exotic higher vertebrates in Mexico: diversity, distribution and potential effects. Institute of Ecology, National Autonomous University of Mexico. SNIB-CONABIO databases. Project U020. Mexico. DF
  • Cook, RE (1979). Asexual reproduction: a further consideration. The American Naturalist, 113 (5), 769-772.
  • De Meeûs, T., Prugnolle, F., & Agnew, P. (2007). Asexual reproduction: genetics and evolutionary aspects. Cellular and Molecular Life Sciences, 64 (11), 1355-1372.
  • Dieckmann, U., & Doebeli, M. (1999). On the origin of species by sympatric speciation. Nature, 400 (6742), 354.
  • Komen, H., & Thorgaard, GH (2007). Androgenesis, gynogenesis and the production of clones in fishes: a review. Aquaculture, 269 (1-4), 150-173.
  • Thorson, G. (1950). Reproductive and larval ecology of marine bottom invertebrates. Biological reviews, 25 (1), 1-45.

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