How can the extinction of an organism be inferred from evidence in the fossil record

Through time the different species faces some of the most unusual form of environmental factors, as some of the factors include the lack of a natural resources, lack of shelter and along with that some of climatic changes are also held responsible for the survival of the organisms inside the region under consideration or observation.

While, the planet Earth is composed of the different layers of soil and moist, each of the layers consists of the animals that belongs to the different ages and era's in the history of the living beings in a more specified piece of land. We all know that from the scientific analyses that the dead animals are covered by a a sheet of soil(dirt) and water as the time passes on from one generation to another in a given sequence of environmental events.As the different fossils shows the variety of organisms which belongs to the past, or the organism are not found in the current time and space. While, the fossil records provides the basic information regarding each organisms and there way of life.  While, some of the specialized form of rocks are characterized to have these ancient organisms which are dead in the present time or era, while there are professionals who look after these sedimentary form of rock and analyze the fossil record of the various organism that have lived many millions of years ago.