Heterotrophs, whose morphological structure and physiological characteristics are quite different in the ocean. They don't carry out photosynthesis, can't synthesize inorganic substances into organic substances, and can only feed on animals such as plants and microorganisms and their organic debris.
At present, there are about 200,000 known species of marine animals, and their forms are various, including unicellular protozoa under the microscope, and all the way to higher mammals, such as whales. They are widely distributed, from the equator to the polar waters, from the sea surface to the depths of the seabed, and from the coast to the bottom of the trench in the ultra-abyss. Marine animals can be divided into three categories: marine invertebrates, marine protozoa and marine vertebrates.
Extended data:
The ocean is full of life, whether it is in bright shallow water or dark deep water. The ocean is the largest biological habitat on our planet. There are about 200,000 species of organisms in the ocean, and the total mass of marine animals is 32.5 billion tons, which is 3.3 times that of land animals.
If you sneak all the way from the sea surface to the seabed, the bright area is within 200 meters underwater, and the weak light area is from 200 meters to 1000 meters. The water temperature here has also dropped sharply. When you go below 1000 meters, it is the dark area of the deep sea, and the sun can no longer shine here.
These species are diverse in structure and function, and can be expressed from simple to complex one by one. For example, there are sponges with mouths and anus in the digestive tract, coelenterates and flat animals with mouths and anus, and button animals with mouths and anus.
These diverse support systems not only increase the size of individuals, but also allow muscles to attach and move around, so animals can live in various types. Such diverse creatures are good materials for studying and comparing various disciplines.
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