External Fertilization Process

The reproductive process where the male gamete sperm fuses with the female gamete ovum outside the female body. The steps involved in this process are:

  • Synchronization: The most important aspect of external fertilization is the perfect timing and synchronization with the environment. Most of the species rely on this method and they are tuned to certain specific triggers like temperature change, daylight duration, and lunar cycles. The coral reefs exhibit mass spawning during lunar cycles and it ensures the release of gametes by many individuals at the same time. This increases the chance of the gametes meeting and results in successful fertilization.
  • Release of Gametes: This is the primary step in the external fertilization process, the male and the female species release the sperm and egg into the surrounding environment. The release is done by complex courtship behavior which signals the spawning. In certain species of fish, the males and females come together in groups and release their gametes at the same time which maximizes the chances of fertilization.
  • Gamete Fusion: After the release of the gametes into the water, the sperm finds the egg and fertilizes it. This process is influenced by water currents, the concentration of gametes in the water, and the viability of the sperm and eggs. In certain species, eggs emit chemical signals that attract sperm and they fuse to form a zygote.
  • Protection and Development: After fertilization the resulting zygote faces challenges in surviving in the open environment so many species develop certain strategies like laying eggs in protective cases or attaching to rocks or plants. In some cases both the parents guard the egg until they are hatched. The development of embryos into larvae continues in the aquatic environment.

External Fertilization – An Overview

External fertilization occurs in fish, frogs, and certain invertebrates like sponges. External fertilization is the process of reproduction where the fusion of the male gamete and female gamete takes place outside the body in an external environment. This type of reproduction has various benefits as it has great biodiversity and the chances of survival are also higher. In this article, we will study the process of external fertilisation, examples, features and more.

Table of Content

  • What is External Fertilization?
  • Characteristics of External Fertilization
  • External Fertilization Examples
  • External Fertilization Process
  • Advantages of External Fertilization
  • Disadvantages of External Fertilization
  • External Fertilization in Humans
  • External Fertilization in Plants
  • External Fertilization in Fish
  • Difference Between Internal and External Fertilization

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What is External Fertilization?

External fertilization is a widespread reproductive method that takes place in the aquatic environment. The fertilization method takes place during the process of spawning where the females release their eggs and the male releases sperm in the same area and same time. External fertilization takes place in crabs, shrimps, oysters, squid, sea urchins, and sea cucumbers....

Characteristics of External Fertilization

The features of external fertilization are as follows:...

External Fertilization Examples

Many aquatic species follow the external fertilization process. Some of them are:...

External Fertilization Process

The reproductive process where the male gamete sperm fuses with the female gamete ovum outside the female body. The steps involved in this process are:...

Advantages of External Fertilization

External fertilization has certain advantages:...

Disadvantages of External Fertilization

Although external fertilization has many advantages it also has certain disadvantages, like:...

External Fertilization in Humans

External fertilization is also seen among humans but it is not natural. When the female’s oviducts are blocked the sperm cannot reach the eggs to fertilize it. In this situation the doctors collect the eggs and sperm and keep it together for several hours for the fertilization to take place this is known as in-vitro fertilization. After fertilization, the zygote is transferred into the uterus of the female after a week and the development takes place inside the body of the female....

External Fertilization in Plants

In plants external fertilization is very evident in primitive forms like algae and mosses where the male gametes are released into the environment and they finally reach the egg cell through chemotaxis. When fertilization occurs, the zygote develope individually independent of the mother plant. Pollination is also sometimes considered as an advnce form of external fertilization where the pollen is carried by an agent to the female plant....

External Fertilization in Fish

Fishes usually exhibit external fertilization. In this process the female fish lays egg in water and the male fertilizes it by releasing sperms on the cluster of egg. Once fertilization is successful, the male parent cares for the egg until they hatch....

Difference Between Internal and External Fertilization

The difference between internal and external fertilization in points is listed below:...

Conclusion – External Fertilization

External fertilization is the method of fertilization that takes place outside the female body. Here, the male and the female gametes are released into the aquatic environment and the fusion takes place. This type of fertilization is seen among aquatic organisms like fish and amphibians. External fertilization has high productive output and genetic diversity but it also has significant risks and challenges for the survival of offspring....

FAQs on External Fertilization

What are Internal and External Fertilization?...

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