Nature invented quite a few breeding mechanisms. The simplest organisms, such as bacteria, are simply divided in half. But more complex creatures should use other ways. As a result, with the variety of living beings themselves, the structure of their reproduction also changes.
One of the most popular ways to acquire offspring is laying eggs. Not born yet the kid is reliably protected by a dense shell, ripening inside under the supervision of parents, and sometimes without. And the eggs themselves are so unusual that it’s time to talk about them.
Eggs in most of these formidable marine inhabitants, as well as in skates, have a very strange shape. It is also called the purse of a mermaid. The egg is located inside a thin capsule, which is filled with collagen. At the same time, the filamentous genital depositions of sharks are an unusual square or rectangular shape, whose angles can be pointed. Often outlines may be another, no less bizarre shape. Shark eggs are often washed ashore, they usually have a size with the palm of a person. But there is a fixed record of 2 meters. Having fertilized the eggs, the shark leaves them on the bottom. There they lie, not needing maternal care, until the very birth of the cubs. It happens that in some eggs a few sharks are born. Nature gives the chance to appear us light only to one of them – the strongest eats the rest.
Eggs of an octopus.
Egg octopus eggs are soft and half transparent. These creatures with tentacles leave them on corals or protrusions of stones. Female octopus at a time lay hundreds of thousands of eggs. But unlike sharks, these creatures do not abandon their offspring, staying close to it until it comes to light. After all, you need to protect the eggs from those who want to eat unprotected food. Often this can last so long that the hunger for survival will force the female to eat some of her eggs. And by the birth of small octopuses, they can eat only tiny marine microorganisms, such as plankton. Only when the cubs grow, they begin to develop the seabed, leading an adult way of life. But for their mother, watching eggs is often fatal – a weakened creature is usually eaten by some of the predators as soon as they exit the lair. The female octopus does not have the strength to resist and fight for her life.
Pisces differs from octopuses and sharks from the fact that most of their species do not mate at all. The female releases unfertilized eggs, or lays them off somewhere. Then it’s time to work for the male – he covers them with his “sperm”. Nature has made it so that some male and female individuals of one species never even meet. In this case, almost all fish, unlike the octopus, do not remain near their eggs to protect their offspring. In this case, the fry is given the opportunity to develop independently and hope that they will not be eaten before birth. And at one time a female fish lays millions of eggs, so that even the coldest predator can not destroy everything at once. In this case, eggs are sometimes deposited even on unprotected surfaces, such as rocks. Often, fish eggs generally drift right in the water, traveling hundreds of kilometers. This phenomenon is called ichthyoplankton, it refers to the travel of fry even before their birth.
A person is much more used to dealing with bird eggs. Usually female individuals, like most reptiles, incubate their fertilized eggs. Parents protect their young ones until they are born in a specially built nest for these purposes. But even after birth, the chicks still remain helpless, needing the patronage of their parents. Birds in the shell of the egg include calcium carbonate, which is the main component in pearls and sea shells. And for safety, nature has provided a different color for bird eggs.Curiously, eggs can be slightly deformed on one side, this is explained by the constant pressure still inside the mother. But this property even turns out to be useful for some birds. Because of this, eggs roll around in a circle, and do not roll away from the nest. Many birds with incubation create their tight little world with a constant temperature. And there are also such birds who do not want to breed their chicks, throwing them to other, more gullible parents.
Despite the fact that these animals have long been extinct, scientists are faced with their fossilized eggs. There they find tiny petrified cubs, which makes it possible to look at millions of years ago. It turned out that the eggs of the dinosaurs were quite different in shape. Some resembled extended spheres, there are those that are more like a tablet. Some eggs shaped like tears, but were round, like a sphere. Some species of dinosaurs deposited many eggs and protected them, but there were also those who laid eggs, and then did not worry about their protection. Scientists were able to detect genital deposits of a wide variety of forms. Almost all of them differ in their form and composition from those that are deposited by birds and reptiles. The eggs of dinosaurs were much larger in size than in any other living thing. The largest of those found was about 60 centimeters in height and 20 centimeters in width. At the same time, the shell of the egg contained tiny pores, through which air entered the embryo. A too large egg for the fortress needed a thick shell, which made it difficult to access the air to the embryo.
Eggs of sea sponges.
Although sponges and corals have little to do with fish, their eggs are laid in a similar way. These creatures have no division into the male and female sex. The organs for reproduction in each individual are from both sexes. They release eggs and semen into the water. And some sponges also multiply asexually, without having organs for that. They simply release cells that grow into new individuals. For this and fertilization, no need. Some sponges can reproduce, simply by dividing into parts. Subsequently, each of them becomes a new independent organism. It is curious that the reverse process is possible. Some types of sponges after separation can reconnect, turning into a new organism. If the parts of the body are placed at a distance from each other, then each sponge will simply begin to live its own life.
Eggs of insects.
Many insects have a rather careful attitude to their male’s sperm. The fluid obtained as a result of mating is stored later in the body to be used for subsequent fertilization. This is a very rational decision of nature, because not all males for a number of reasons can survive mating. Insects usually lay many eggs at once, sometimes building entire nests or unusual nurseries. But eggs can have a very unusual shape. To keep them from predators, insects have learned to mask their future offspring well. It also happens that eggs are deposited even in water. Newborn insects already know how to live under water, only then they go out into the air. Many insects are also able to take care of pending eggs. For example, termites and ants support even a certain level of humidity around them.
Eggs of amphibians.
These amazing animals begin their life in the water, only adults live on land. Their amphibian eggs are also deposited in water, often also surrounded with a special gel. This substance keeps objects together. When the tadpoles hatch, they do not yet have limbs, but the gills are already present. They float in the water, like fish. But the mouth of tadpoles is not yet, they absorb the remains of their eggs through the skin. Only with time the lungs and limbs grow, the tail disappears, the mouth appears – this is how the adult is formed.Thus, the egg is not only a home for amphibians, but also a meal. Some frogs also have a concern for their offspring in the event that there is not enough water nearby.
Biology suggests that single-passages originated from reptiles, being the ancestors of modern mammals. But for today there are only two types of single-pass – echidna and platypus. These creatures are warm-blooded. They have hair follicles and can even give out milk, which relates them to mammals. But monopods have a distinctive feature from mammals – they lay eggs. There is one more difference from reptiles and birds – even when the eggs are found inside the mother’s body, nutrients are provided to it, similar to how it occurs in mammals. Eggs in single-pass are small, spherical and white. These creatures postpone their future offspring in a burrow, and when they hatch, then even up to six months the mother cares carefully for them and cares. The platypus tries to keep the laid eggs in the heat, for this it covers them with its tail. But echidna simply hides eggs with her body. But these kids feed these animals, although milk, but not from the nipples. Nutritional fluid is allocated instead of sweat, giving food to the newborn.
This term implies the birth of live kids. Sometimes they are in the egg right up to the moment, but before they hatch inside their mother. This is rare in fish, snakes, scorpions, cockroaches and other animals. For example, in sea horses, a female specimen passes her eggs to her male. He and carries them until the children are born. But in mammals, as in higher beings, the egg shell does not appear at all. The embryo is completely formed inside the mother’s body, which through the placenta gives him nutrients. Viviparians require much more energy than the usual egg-laying mother spends. Nevertheless, this way of procreation allows birth to much more complex creatures, this is a step in evolution. Viviparia naturally causes parents to take care of their descendants and to accustom their lives in a complex world, instilling the skills necessary for survival. Oviparous children already have all the necessary knowledge and skills for a future life in nature. But the mammal has to learn everything. But these creatures are able to live a much wider range of environments than obey the oviparous animals.