来源:沪江英语
小编:Lucy 80Reading
①
Climates have a lot of things to do with people’s life.The N’s tribe is one of the most obvious examples to show us how climates can affect people’s life.This N’s tribe used to live in the younger dry times and they lived in a wild life style.However,climates was gonna change and it turned dry.The river and the source of water turned dry day by day with the games turned less and less.The drought made the N’s tribe difficult to find any food to make a living in a wild life style.So that people needed to invent much more precise hunting skills in order to make a living.In order to hunt more for food,they invented new tools,like the arrowhead.
But they still could not get enough food so that they moved,then settled and tried to find new ways to live on.They happened to start to cultivate rye crop,and “tamped” wild rye generally.This became a new food resource for them and support them for a short period.Archaeologists found the rye in a small village at around 11100 to 11020 B.C,which is the first man-made rye in our history.But this did not work for too long because of the growing human beings.The amount of people were growing bigger and bigger so that they could not just live on those small amount of rye.In order to solve this problem, they bronzed their scale of hunting and started to plant more grains.Even so,this still could not support their life or satisfy their demand.So they just changed from settling down back to nomadism.As a related consequence of that was the domestic rye went back to wild.
The N’s tribe used to live in woodland where their ancestor lived for hundreds of years.Because of the change of the climate,the turning from humid to drought,with the process of arid of the water source,they could not make a living just in woodland.So they moved to Jordan river,where there were fertile soil and full source of water.
② Metamorphosis
It is acknowledged that amphibious animals have to go through the stage of metamorphosis before they evolve into mature ones. There exists some protection actions, which are called metamorphosis, during the process of transforming into pupil from juvenile, and moreover, the process of metamorphosis always lasts for several hours or even several days. Then they will finally turn into the adult. For instance, tadpoles can evolve into frogs and larvae can evolve into butterflies, and all of these action can be assorted as the metamorphosis.
The things in the nature always possess the reasonable advantages because of which they could survive in the process of natural selection. What are the advantages and disadvantages of the metamorphosis? As for the advantages, they can assign their life cycle effectively, with the consideration of different environment. But also due to the ability of doing effective plan, they have to consume a large amount of energy to support their behavior. Why do they choose this approach with such vast energy being consumed?
Let us take the metamorphosis of frogs as an example. Mostly, the spawns of frogs are always born in a fierce environment, which is not suitable for their survival and development. That is why the frogs are inclined to consume most of their energy on the life cycle containing the reproduction and laying eggs stages. It is the same with the situation of the butterflies, that is to say, they also choose the stage which is considered as most significant to consume their energy.
However, it is difficult for all these animals to go through this stage, since some of them will be given birth in a mild environment, in which , they possess sufficient water and food to support their life, and in addition, the climate or temperature are also suitable for their survival. In this situation, these animals will ignore the stage of metamorphosis.
So with the explanation above, we can conclude the situation of possessing metamorphosis. If the juveniles of animals are born in a fierce environment, in order to survive, they have to go through metamorphosis, if not, they are likely to ignore the metamorphosis. Owing to the fact that, the environment in which these animals live in can change with the time passing by, they probably change the stage with the changing climate.
③ Coral reef
Generally, the coral reefs always can be assigned as three types: atoll, barrier reef and fringing reef, and all of these organisms let the sea world become a colorful one. Some scientist claim that the atoll always get together near the Indian Ocean, which contains huge lagoon. As for the barrier reef and the fringing reef, we can find them everywhere, and they are difficult to be distinguished from each other by scientist, that is why they are usually considered as the same kind.
Referring to the Darwin suppose, the atoll which lives in the volcanic island can gradually transform into barrier reef with the force produced by precipitation of sea water, ultimately turning into the fringing reef. This theory not only provides an explanation to the formation of lagoons, but also clarify the reason of its existence. However, this theory cannot explain all the formation of barrier reef and fringing reef, since the natural phenomenon has various reasons and the slow process of precipitation is necessary.
With the time passing by, many scientist has queried the Darwin suppose, with some evidences as well as analysis brought about, however, one specialist drilled the limestone which was more than 3000 miles deep, figuring out the atoll layer on the volcanic island, which support the Darwin suppose directly. It also attracted thousands of scientist put weights on researching it.
Even though this scientist has provided us with strong evidence to support the ancient theory, we cannot easily conclude the explanation of the formation due to the complicated natural situation. If one day, specialist can collect all of the documentary of these formations, we maybe can get one conclusion and give the through explanation of this phenomenon.
Considering the atoll can be found in a dense area and easy to discover as well as analyze, scientist have some significant materials for individuals. It is acknowledged that the atoll cannot form in the ocean in which the precipitation is quick and to some degree, it may be difficult for them to find the barrier reef or fringing reef.