By understanding this history, we are able to find a simple relationship about the habitat we used to be living was. The oceans including above, middle area or the floor are the habitats for living things. Therefore, our ancient home is not only for doing simple activities such as eating, breathing, moving or something related to those but also the biological activities including the mating process. And as far as we know the evolutionists' perspectives suggest us that the mating process for living thing are different depends on the habitats.
Interestingly, for animal who lives in the sea is more likely to do external fertilization. This process invites the eggs and the sperm to be fertilized outside the body. It means, if the female who keeps the eggs so that they can be fertilized spreads the eggs firstly in some place and the male then sprays it sperm. This process is known as the external fertilization with nest builders since the female selected the certain places for laying eggs and the opposite is broadcast spawners. Nevertheless, both of two types of fertilization are occurred outside the body and they conclude two things.
The first amazing thing is the external fertilization can be assumed as the spreading of DNA of some living things. As we know that the laying eggs process occurred in nest builders invites the male to fertilize by spraying its sperm. This process can increase the opportunity about the trace of unsuccessful sperm in fertilizing the eggs. What am I trying to say that is there any possibility of dead sperm or the corpses of unsuccessful sperm are still existed until now? This answer can lead us into the understanding of ancient genetic code in the oceans.
The second important thing we can achieve from those two types of external fertilization is the spreading population. The broadcast spawners created the high competition of sperm in accordance of the length distance of the location of the nest. The opposite type led to the closest males to do the fertilization. So, based on the location of the nest and the location of residual fertilization process we are able to determine the location of certain species. It is similar like the fossils in the land, however the different is in the oceans' currents.
Overall, many of our ancestors according to evolutionists were evolved from sea creatures. Based on this understanding we can assume the biological activities happened on the floor, above or middle part of the sea. Therefore, the trace of genetic code could be until today can be found in those three areas in the oceans.