Difference Between Fertilized and Unfertilized Eggs

Fertilized vs Unfertilized Eggs

The difference between fertilized and unfertilized egg arises as the result of the biological process the eggs undergo. The female gamete is usually called an egg. We divide these female gametes or eggs into fertilized and unfertilized egg based on the process called fusion or fertilization. The following article explains this process involved and the difference between fertilized egg and unfertilized egg that is caused by this process.

What is a Fertilized Egg?

Fertilized egg is also referred to as a zygote in the process of development. Fusion of the haploid female gamete (ovum) with a haploid male gamete (sperm) to form diploid zygote is called fertilization. Hence, fertilized egg finally produces a diploid organism by mitotic division. There are two types of fertilization, namely; (a) internal fertilization where fertilization occurs inside the female body and (b) external fertilization, where fertilization takes place outside the female body. Once the zygote is formed, it undergoes rapid cell division to produce a new organism. The zygote is capable of producing all kinds of cells in an organism’s body. Because of the fusion of male and female gametes to produce a diploid organism, we call this process ‘sexual reproduction.’

Difference Between Fertilized and Unfertilized Eggs

What is an Unfertilized Egg?

An unfertilized egg is an ovum, which has not been fused with a male gamete (sperm). Since an unfertilized egg is not fertilized, it is always haploid and only one set of chromosomes is found in it. Because of the absence of fertilization, an unfertilized egg never produces a diploid offspring by sexual reproduction. However, some plant and animal species have developed alternative reproductive methods to produce their offspring through unfertilized eggs. These methods are known as asexual reproductive methods. One good example for this is parthenogenesis, which is common in many species of arthropods. In addition, some lizards, fish, and salamanders also show parthenogenesis. Some species are exclusively parthenogenic, whereas some can switch between sexual reproduction and parthenogenesis. In honeybees, for example, the queen can store and control the release of the sperms. When she releases sperms, the eggs develop sexually into diploid female worker bees. If no sperms are released, the unfertilized eggs develop parthenogenetically into haploid male bees.

 Fertilized vs Unfertilized Eggs

What is the difference between Fertilized and Unfertilized Eggs?

• Definition of Fertilized and Unfertilized Eggs:

• Fertilized egg is formed by the fusion of haploid female gamete with the male haploid gamete.

• An unfertilized egg is the egg that has not been fused with a male gamete.

• Fertilization:

• Fertilization occurs to form fertilized egg.

• Unfertilized egg is formed in the absence of fertilization.

• Development:

• Fertilized egg is always developed into a diploid organism.

• In some organisms, unfertilized egg can produce haploid organisms.

• Reproductive Method:

• Fertilized egg is formed during the sexual reproduction.

• Asexual reproduction leads to form offsprings by unfertilized eggs.


Images Courtesy:

  1. Fertilization of an egg with a sperm via Wikicommons (Public Domain)
  2. Unfertilized Egg by Chippolito (CC BY-SA 3.0)