What is the main problem with external fertilization, and how is this comensated for?
tried finding the answer but cant help
This chapter will give you some idea.
http://www.mhhe.com/biosci/genbio/rjbiology/ELOs/ELO52.html
The main problem with external fertilization is the lack of control over the environment in which fertilization occurs. In external fertilization, male and female gametes are released into the external environment, such as water, and rely on chance encounters for fertilization to take place. This method is commonly observed in aquatic organisms like fish, amphibians, and many invertebrates.
The major challenge with external fertilization is the high degree of predation and dispersion of the gametes in the surrounding environment. Factors such as water currents, waves, or other organisms can scatter or destroy the gametes before fertilization occurs. Additionally, the large number of gametes often released increases the likelihood that only a few will successfully encounter each other, leading to wastage of reproductive investment.
To compensate for these challenges, organisms that rely on external fertilization have developed various adaptations. One common strategy is the production of a large number of gametes. By releasing a large quantity of gametes into the environment, the chances of successful fertilization increase. This is why you often see fish or frogs producing thousands, or even millions, of eggs.
Furthermore, many species engage in behaviors that increase the probability of successful fertilization. For example, some fish build nests for eggs, while others perform elaborate courtship rituals to attract mates and synchronize the release of gametes. These behaviors help to bring male and female gametes in close proximity, increasing the likelihood of successful fertilization.
Overall, while external fertilization has its drawbacks, the strategies of producing a large number of gametes and engaging in behaviors to enhance encounters between male and female gametes help compensate for the challenges and ensure successful reproduction.