Few people think about the fact that each stagelife has its name. So, science knows embryonic and postembryonic development. These periods are very different from each other and have different characteristics. The article will discuss what kind of development is called postembryonal development. You will learn the types of this period and features.
The moment when the embryo leaves the fetusshell, is a transition from the embryonic period to the postembryonic period. In the people this time is called birth. It is worth noting that in different living organisms this process is very different.
The post-embryonic period can be characterized by two kinds of development. Science knows the direct and indirect transformation of a living organism.
Direct development
This type includes the transformationan organism that is very similar to an adult. So, postembryonic development of a person has a direct form. This also includes the development of animals and some reptiles.
After the birth of the embryo is very much like an adult organism. However, it differs in size and lack of skills.
Indirect development, or metamorphosis
The post-embryonic period may have an indirect form(metamorphosis). In this case, an organism appears from the membranes, which differs greatly from the adult. This includes some invertebrates, mollusks and reptiles. As an example, you can take an ordinary butterfly. Postembryonic development of the organism in this case is characterized by being in the form of a larva. Only then the butterfly becomes like an adult.
As already mentioned above, immediately aftera new organism leaves the membranes, a new stage in development begins. The post-embryonic development of man is divided into several stages. The final stage is puberty. Let us consider the main stages of the postembryonic period.
At this stage, the baby adapts to the newenvironment. He learns to hear and focus his views on certain things. The food at this stage of development is exceptionally liquid. The kid still can not eat adult food by himself and is completely dependent on the mother. Some children are faster in development than others. They move to the next degree of the postembryonic period faster. So, some kids in six months can already stand, sit and crawl. However, these are only physical skills. Science still does not know the case when the child at this stage began to speak a clear adult language.
It should be noted that many animals andreptiles that pass the direct path of postembryonic development, live in much the same way. However, they can pass this period much faster than a person.
At this stage, a small person learns to sitcrawl and walk. This stage is characterized by the acquisition of physical skills. Also, the young organism begins to gradually become accustomed to new food. At this stage, many children begin to make new sounds. So they learn to speak in a language understandable to an adult. If a child develops faster, then at this stage he can already speak some words or even simple sentences.
Reptiles and animals in this period are already fully ready for adulthood. They themselves can get their own food and are no longer dependent on adults.
The human body is characterized by the mostlong postembryonic development. At this stage, the child can already fully support himself, but to live without parents is still very difficult for him. In ordinary life, children at this stage attend pre-school, and then school institutions. They grow, develop and learn everything that is useful to them in their adult life.
Mammals and animals at this stage have completely passed the postembryonic period and are considered adult individuals.
So what kind of development is called postembryonic,you already know. In humans, it ends in about 16-20 years. At this stage important parts of the body begin to work. The pituitary and adrenal glands produce certain hormones. Women begin to function as ovaries and menstruation appears. Men also acquire sexual maturity and are able to continue their generation.
The postembryonic period ends with the transition to adulthood. A person is already able to live independently and create his own family.
As in the previous case, this development is divided into several main stages. Let us consider them in detail.
Immediately after the body leaves the fetusshell, its further transformation begins. At this stage, the new individual is completely different from the adult. It is very different in appearance and internal development.
At this stage, a strongtransformation of a new organism. Every kind of living creature has it in different ways. The individual looks like an adult animal or mammal. However, many organisms at this stage still need care and protection. They can not provide themselves for the time being.
Indirect postembryonic development hasThe final stage, which is characterized by the acquisition of certain skills. They will help the future organism to live independently and not depend on extraneous individuals.
Now you know what kind of development is called postembryonic. It should be noted that the indirect transformation occurs much faster than the direct postembryonic period.
The person undergoes the longest course of the givenstage. However, human skills can survive even in the most difficult conditions. This can not be said of reptiles or animals. Behind the development of man in the postembryonic period, some doctors watch: a pediatrician, a neurologist and others. Parents' parents are also especially attentive.
Everyone should know what the post-embryonic period is. Initial data about this time are known from the lessons of biology. It is this kind of information that helps to develop your own world.
