Deck 9: Marine Reptiles, Birds, and Mammals

Question 1

Sea turtles have disappeared from many regions, and one way of trying to save them is to reintroduce them to areas where they have been wiped out. This is done by reburying eggs or by releasing newborn baby turtles on beaches. Why are eggs reburied or baby turtles released instead of fully-grown individuals?

Answer 1

Sea turtles are the reptiles present in the marine environment. These are air-breathing large organisms that do not have teeth. These organisms have been constantly killed for various purpose including decoration and food. It is necessary to ensure that these organisms are maintained and does not get extinct.
It is advisable to bury the eggs of sea turtle near the beaches where they had been wiped out instead of releasing adult turtles. There are several reasons behind this. The sea turtles have the ability to remember and adapt themselves according to their place of birth. Therefore, allowing the turtles to take birth near the destined sea beaches allow them to remember their place of birth and adapt accordingly. This could help in easy establishment of the turtles in the region.

Question 2

Most seabirds are specialists that feed on particular types of fish and other prey. In some cases, this may reduce the chances of competing with other species of seabirds for limited resources. Sometimes, however, we find two or more species of seabirds feeding on the same type of fish. What type of mechanisms might have evolved to prevent direct competition?

Answer 2

The abundance of fishes and insects sustaining in the marine environment is responsible for attracting and supporting a wide range of amphibians, mammals, reptiles, and birds. These organisms are directly dependent on the marine life. These organisms may directly or indirectly involve in competition with each other. Many organisms develop different mechanisms for avoiding such competition.
The seabirds usually do not compete with the members of other species for food. There are certain exceptions where the fight among the seabirds has been documented. Such fights can be easily prevented if the birds feed at different areas for example near sea shore, offshore, etc. It can also be avoided by feeding at different times, for example feeding in the morning, evening, or night. Changing the feeding habit is another option available for avoiding competition.

Question 3

Cetaceans give birth to a few well-developed calves at well-spaced intervals. They also feed and protect the calves for long periods. This is in sharp contrast to most fishes, in which many eggs are spawned and the parents spend no time feeding and protecting the offspring. What do you think is the best strategy? Has this effort paid off in the case of the great whales?

Answer 3

Cetaceans are the group of aquatic mammals such as whales, porpoises, and dolphins. These individuals can breathe in air and can give birth to young individuals. These organisms have hair and can produce milk for the younger ones.
Cetaceans are organisms belonging to the class Mammalia. These organisms are known to give birth to young ones instead of eggs in most of the fishes. They also produce milk and take care of their young ones.
This strategy of taking care of the young one is due to their property of "k selection". The adults give birth to fewer offspring, thus it is important to take care of the young individuals. The best strategy is "r selection" where the individual produces large number of offspring and does not take much care of them.
This strategy of "r selection" provides the chances of survival to large number of individuals thus increasing the chances of the continuation of species. The principle of "k selection" did not favour great whales as they were hunted in larger extent and thus pushed to near extinction status.