The Ovulíparos Are the living beings whose fertilization and development occurs in eggs within the water, that is to say that belong to the category of the oviparous.
These animals are characterized by reproducing through external fertilization, which means that the development of the embryo occurs in a medium outside the female, particularly in water
Trout, an ovulíparo fish
The animals are classified, among other things, by their reproduction, which in turn guarantees their survival in the ecosystem Because each animal is able to originate another being with the characteristics that define it.
Many living things form in the womb of your mother or develop into an egg. Considering this principle the animals can be classified in oviparous, viviparous or ovoviviparous. Next we specify the first species of them.
The etymological definition of oviparous comes from the Latin ovipărus (ovum = egg and pariré = parir). Animals that reproduce by this means deposit their eggs in an external environment to complete their embryonic development until the hatching or birth of the animal.
To this category of living beings belong the majority of amphibians, fish, insects and reptiles.
However, there are among the mammals a species of oviparous animals represented by the platypus and the echidnas that use this means of reproduction.
Characteristics of ovulíparos
Among the oviparous, two classes are distinguished: the animals that deposit their eggs in the air after having been fertilized inside the female, as is the case of insects, reptiles and birds.
The other category is those animals that originate soft eggs deposited in an unfertilized aquatic environment, such as amphibians, fish and crustaceans.
This process is known as external fertilization and consists of the expulsion of sperm from the male on the eggs that are deposited by the female. These animals are identified with the name of Ovulíparos.
It is important to note that each animal species differs according to the breeding season and the number of eggs it produces.
An example is the case of Sea turtles S capable of producing between 70 and 190 eggs while some birds reach a reproduction below two dozen.
The forms of reproduction vary in all species belonging to the same category of oviparous animals. Crocodiles and alligators, for example, tend to their eggs and when hatching are kept close to their young.
For their part, reptiles are characterized by giving up their eggs and at birth, the offspring are autonomous and manage to survive without their parents.
Also, the place where they lay eggs and the making of nests varies from one species to another. The turtles bury their eggs in the sand, which remain there until hatching.
The birds, on the other hand, make nests on the top of the trees where they keep hatching the eggs until the birth of the young that will later be protected and cared for until they achieve independence and autonomy to fly and survive.
In the evolutionary chain, oviparity is an advantage for many species because the embryos develop independently, since the structure of the egg keeps the creature protected during its formation as long as the nest egg is not Thanks to the predators.
TO The gelatinous substance that covers the embryo provides the necessary nutrients to evolve correctly until the moment of hatching.
Ovuliparous and external fertilization
This process of sexual reproduction is characteristic of fish, amphibians and crustaceans, the former being the largest species that reproduces through external fertilization. The reproduction process occurs in three steps:
- The female looks for safe places and away from the predators to expel the eggs.
- The male attentive to the work of the female, places the eggs and expels its sperm on them to be fertilized, from this moment the zygote or egg cell is formed. It is particular of this type of reproduction that the eggs do not have a hard shell, on the contrary their coating is soft to adapt to the aquatic environment.
- Finally, the egg develops naturally without the presence of the parents, which in turn compromises the continuity of the species, because if the place is not appropriate they can be exposed to predators.
Examples of ovulíparos
The most representative animals of this category are the majority of small fish besides the pejerrey and the trout.
Amphibians like frogs and mollusks like the mussel are also ovulíparos.
Stars and sea urchins are the echinoderms known to reproduce through ovuliparity. While among the ovulíparos crustaceans is the shrimp, the shrimp, the crab, among others.
Frogs in particular reproduce when the male stimulates the female through a process called amplexus so that it releases its eggs to the outside. Once expelled, the male fertilizes them, weeks later the pups will be born after they develop in the gelatinous liquid of the egg from which they are released upon reaching the incubation time.
The female clams have the ability to release millions of eggs in the sea, which then become larvae fixed to surfaces firm to be fertilized by the male to give way to gestation that lasts about two weeks.
The sexual maturity of these molluscs is reached at one year of age and the process of external reproduction is repeated.
In the case of sexually reproduced starfish, ovuliparity occurs when eggs that were not fertilized are released into the sea, reaching the same place where the males release the sperm, producing external fertilization.
The embryos develop during gestation thanks to the nutrients they absorb inside and feeding on other eggs of their species to survive.
References
- Gestation of animals. Recovered from: gestacionde.com.
- The animals files. Retrieved from: theanimalfiles.com-
- Wikipedia, the free encyclopedia. Ovuliparity. Retrieved from: wikivisually.com.