Marine animalsPosted on May 18, 2018 - Last modified: November 8, 2018
Marine animals, also known as sea animals, are those that spend all or most of their lives living in the sea. Discarding the river animals and lake animals, that although they are aquatic animals, they could not withstand the salinity of seawater.
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We can find a large ecosystem that has an extensive biodiversity of species and plants, in fact it is so large that scientists are unaware of all the species that inhabit the seabed.
In the sea live numerous species of fish, reptiles, birds, mammals in the group of vertebrates, the invertebrates being the cnidarians, echinoderms, sponges, marine worms, crustaceans and mollusks.
For more information visit the section on aquatic animals.
Sea animals are the most diverse on the planet and it is important to note that there are marine animals that do not live in the sea all the time. Marine animals can be classified into two large groups:
- Non-strict marine animals: These marine animals do not carry out their life cycle (they are born, grow, reproduce and die) totally in the sea since they need a surface of land or rock to survive where they rest or reproduce. They dive into the sea to feed. Some of these animals may be the Penguins, the seals o sea lions.
- Strict marine animals: These marine animals carry out their entire life cycle inside the sea, since outside the sea they would be unable to survive like whales, sharks or dolphins.
Most species are omnivorous animals. Crustaceans (such as Antarctic shrimp) consume zooplankton (microscopic animals) which in turn feed on phytoplankton. Carnivorous species feed on other fish.
To survive sea animals, most species have gills to breathe. Although we can find exceptions such as turtles or whales that have lungs.
Tides and currents
The entire sea is dominated by the movements that gravity exerts on the oceans. Defined as tides and currents. These movements affect the life of animals that have had to adapt to survive.
As we go into the depths of the oceans, so does the pressure and the sun's rays. We define pressure as the force that a liquid, gas or solid exerts when it is increasing will begin to damage the tissues to the point where it can kill.
A human can withstand 21 times the atmospheric pressure, that is, about 214 meters deep without any type of equipment. But some animals have developed a great resistance to pressure and can survive in these extreme conditions. To achieve this, most have discarded their skeletons, turning into invertebrate animals, since the ideal body is a gelatinous one and their organs must store a large amount of oxygen because at great depths it is very scarce.