Question

Where is jelly deposited as a covering on the egg of frog? (a) In the oviduct (b) In the water during fertilization (c) In the water after fertilization (d) In the ovary

Short answer

The jelly is deposited as a covering on the egg of a frog in the water during fertilization (option b).

Step-by-step solution

Understanding Frog Reproduction

To solve this exercise, one must understand the reproduction process of frogs, particularly how the eggs are protected after they are laid. Frogs lay eggs in water, and they are immediately covered with a jelly-like substance. The jelly serves multiple purposes, including providing a protective layer and facilitating fertilization by allowing sperm to travel through the water to the eggs.

Location of Jelly Deposition

The jelly is not deposited within the reproductive organs of the frog (such as the oviduct or ovary), but rather it is secreted around the eggs as they are laid in the water. This process occurs outside of the female's body.

Determining the Correct Answer

Based on the understanding of the frog's egg fertilization process, we can conclude that the jelly covering is deposited during the process of laying the eggs in the water. Therefore, the correct answer would be directly in the water during the laying and fertilization process.

Key concepts

Reproduction Process of Frogs

Understanding the reproduction process of frogs is crucial for students who are navigating biology concepts. Frog reproduction is typically a seasonal event that occurs in water environments such as ponds, lakes, or streams. The whole process is quite fascinating and starts with a mating ritual, where the male calls to attract a female. Once a female responds, the male climbs onto her back in a position known as amplexus.

During amplexus, the female releases eggs into the water, which are immediately fertilized by the male's sperm. This external method of fertilization is common to many amphibians, including frogs. Frogs are prolific breeders, with some species laying hundreds or even thousands of eggs at once. These eggs, surrounded by protective jelly, will develop into tadpoles if they are fertilized and not eaten by predators.

Frog Egg Fertilization

Frog egg fertilization is a unique aspect of their reproductive cycle called external fertilization, which differs significantly from the internal fertilization seen in mammals. After a female lays her eggs, the male frog immediately releases sperm over the eggs in the water. This process is known as spawning.

The water plays a crucial role in the fertilization of frog eggs, as it helps the sperm to disperse and increases the chances of successful fertilization. The protective jelly that we discussed aids in this process by trapping the sperm near the eggs, thus enhancing the fertilization process. A key point to grasp here is that timing is everything — the jelly is only effective if the sperm is released soon after the eggs are deposited.

Oviposition in Frogs

Oviposition is the process of laying eggs, and in frogs, this occurs in a watery environment. The act of laying eggs is a vulnerability for the female frog, and the protective jelly she secretes is critical for the survival of her offspring. After selecting an appropriate site, which may vary from still waters to fast-flowing streams, the female frog begins the oviposition process.

During this time, the female's body produces the jelly substance that will cover the eggs. This jelly is crucial as it swells upon contact with water, forming a protective buffer for the eggs against physical damage and predators. Not only does this jelly provide a barrier, but it also offers an optimal environment for sperm to encounter eggs and increases the likelihood for successful fertilization.