Question

Compared with external fertilization, in internal fertilization, a. male gametes have a higher chance of coming into close proximity to female gametes. b. gametes are less protected against predation or other harmful environmental factors. c. gametes typically become dessicated. d. gametes come into contact only outside the mother’s reproductive tract. e. Both b and c occur.

Short answer

Option 'a' - male gametes have a higher chance of coming into close proximity to female gametes in internal fertilization.

Step-by-step solution

Understanding the Options

First, it's important to examine each provided option. Option 'a' suggests in internal fertilization there's a higher chance of male gametes getting close to female gametes. Option 'b' suggests gametes are less protected against environmental dangers in internal fertilization. Option 'c' suggests that in internal fertilization, gametes usually become dry or dessicated. Option 'd' insinuates that gametes interact only outside the mother's reproductive tract during internal fertilization. Option 'e' suggest that both options 'b' and 'c' occur in internal fertilization.

Analyzing the Options

Internal fertilization has a higher probability of bringing male and female gametes close together as the process occurs within the female reproductive system, therefore, option 'a' seems correct. Option 'b' is incorrect because gametes are more protected against environmental harms during internal fertilization. Option 'c' is also incorrect because gametes do not usually dessicate in internal fertilization since it occurs in a wet internal environment. Option 'd' is incorrect because in internal fertilization, gametes interact within the mother's reproductive tract. Option 'e' is false since both options 'b' and 'c' are incorrect.

Key concepts

Gamete Proximity

Gamete proximity refers to the likelihood of male and female gametes coming into close contact with each other. In the context of internal fertilization, this aspect is greatly enhanced. Unlike external fertilization, where gametes are released into the environment, internal fertilization ensures a higher probability of gamete proximity since fertilization happens within the body of the female.

This biological process significantly increases the chances of successful fertilization. Internal fertilization allows sperm to travel directly to the egg in the female reproductive system, which is a more controlled and confined space compared to the external environment.

By ensuring close proximity, internal fertilization reduces the number of sperm needed to achieve fertilization, making the process more efficient. This effectiveness is crucial for species where the energy expenditure for producing gametes is high.

Environmental Protection

Environmental protection in the context of gamete survival is a major advantage of internal fertilization. By occurring inside the female's reproductive tract, gametes are shielded from various external factors that could harm them.

In external fertilization, gametes are vulnerable to threats such as predation, temperature extremes, and water currents, all of which can drastically reduce the chance of successful fertilization. Internal fertilization mitigates these risks through a few key points:

• Protection from predators, as gametes are hidden within the body.
• Stability in temperature and environmental conditions, which is crucial for maintaining cell viability.
• Prevention of desiccation, or drying out, keeping gametes in a moist environment necessary for their survival.

By safeguarding gametes from these external threats, internal fertilization enhances reproductive success and ensures that more zygotes develop into embryos.

Female Reproductive Tract

The female reproductive tract plays a crucial role in internal fertilization by providing a supportive environment for the gametes. It is specially adapted to facilitate all stages of fertilization and embryonic development.

The pathway includes several structures, each with its specific function:

• Ovaries: where eggs are produced.
• Fallopian Tubes: the site where fertilization usually occurs; they transport the egg from the ovary to the uterus.
• Uterus: a site for embryo implantation and development.

These components create a secure canal that guides sperm towards the egg, ensuring that fertilization takes place in optimal conditions.

It also offers a controlled environment, rich in nutrients and protective factors, enhancing the likelihood of successful fertilization and pregnancy.