Interesting story | Does land have more survival advantages than the ocean?

Recently, I saw some netizens discussing "Why do more advanced organisms live on land rather than in the ocean?" In other words, is land more advantageous than the ocean for survival? Today I would like to share my views on this issue with you.

First of all, there are three common modes of reproduction: oviparous, ovoviviparous and viviparous. From the general trend of biological evolution, the mode of reproduction evolves with the evolution of organisms from simple to complex and from low to high, that is, from the simple and low-level oviparous mode to the complex and high-level viviparous mode.

The class to which we humans belong is the class of mammals. The word "mammals" vividly points out one of our criteria for the level of evolution: the way of reproduction.

Secondly, the survival of the fittest is natural selection, and every living thing is a favorite of nature. Let's start today's sharing according to the current evolutionary route: fish - amphibians - reptiles - mammals.

01. Oviparous

The definition of oviparity is that the fertilized egg develops independently outside the body. A large number of sperm and eggs combine and then slowly hatch. It can be roughly divided into aquatic oviparity and terrestrial oviparity. There is an evolutionary order (but now it is difficult to distinguish between the two).

Aquatic egg laying. I believe many people have seen many documentaries, where a group of fish lay sperm and eggs in the water, and then slowly hatch.

The disadvantages of this method of reproduction are very obvious

First, water is needed as a carrier.

Second, it is easy to become food for other predators

Therefore, egg-laying relies on quantity to win . As plants began to land on land, fish also began to slowly crawl onto land (having food is a basic element).

Thus, amphibians appeared. The one that everyone is very familiar with is the representative of amphibians.

Amphibians can live both on land and in water, but generally speaking, they cannot be too far away from water sources, especially for reproduction, which they cannot do without water.

Therefore, amphibians are still relatively low-level.

Then, finally, there appeared creatures that could live without water, and that was reptiles, the representative of which was the famous dinosaur.

The reproductive method of reptiles also upgraded the oviparous model to terrestrial oviparous.

In this evolutionary process, we can see that the characteristic of oviparous animals is that an egg contains basically all the resources for life development , but it is exposed to the nature and is easy to be preyed upon.

So evolution continued and ovoviviparity emerged.

02. Ovoviviparity

Ovoviviparity refers to the reproductive method in which the eggs of animals develop into new individuals in the mother's body before they are born. This is the result of long-term adaptation of animals to adverse environments, and is a reproductive method formed by long-term adaptation of animals to adverse environments, which enables the mother to protect and incubate the embryo.

It can be said that this method of reproduction is the first attempt by vertebrates in reproduction.

However, there are essential differences between ovoviviparity and viviparity:

First, ovoviviparous species basically do not communicate with the mother, but exist in the form of eggs (except for the star shark)

Second, ovoviviparity is not like pure viviparity, which leaves everything to the outside world.

Finally, it evolved to a higher stage, which is live birth.

03. Viviparous

The emergence of viviparity can be said to have greatly facilitated the evolution of animals. Unlike oviparous animals, fertilized eggs do not need to be left in the wild to fend for themselves; they can grasp the opportunity of fertilization and constantly adjust the way of reproduction; in addition, viviparous animals have been exchanging nutrients with their mothers, which allows them to develop better. At the same time, our dependence on water is lower.

Okay, this is the general process.

04. Evolution of Biology

From low to high levels of organisms, whether in terms of reproductive methods or breastfeeding methods, they all reflect a process of gradually breaking away from the constraints of the natural environment.

Fertilization: From having to find a random location for fertilization at first, to being able to choose the time for fertilization, to finally being able to fully control the method and time of fertilization

Development: From being unable to live without water at first, to being able to partially leave water, to finally being able to develop completely out of water (although amniotic fluid is also a water environment, the mother can move after all).

It can be seen that the appearance of these animals on land essentially represents an advantage in survival and evolution . Coupled with the limitations of life on land and the influence of the flat world , you cannot jump to avoid enemies, which makes land creatures under greater pressure to evolve. The greater the selection pressure, the more diversity there will be in the end, and naturally the more advanced they will be. As a result, some can run fast, some can climb trees, some can dig holes, and some can build houses.

The advantage of land is that the living environment on land is too harsh , which leads to too much evolutionary pressure , so more advanced animals have evolved.

05. One more thing

Of course, at the end, in order to prevent some people who like to find fault, I would like to add some

First, the evolution of reproductive methods is only one reason for terrestrial diversity. As mentioned above, survival pressure itself is also an important reason.

Second, the evolutionary process of vertebrates is not linear, but diverse. For example, sharks are ovoviviparous.

Third, there are mammals on land, but mammals are not necessarily on land.

A typical example is whales, they returned from land to water.

Fourth, birds. As direct descendants of dinosaurs, birds reproduce by laying eggs.

Also, bats are mammals, not birds.