Scientists used major changes in life forms in the fossil record to form the geologic time scale. select the best answer from the choices provided t f

The right answer is True.

The history of life on Earth shows a succession of fossil species during geological time, each species appearing and developing before disappearing. This is why fossils constitute an archive of earthly history and are used to establish the divisions of geological time.

To date the rock in which they are, fossils are not useful if they belong to a group or species that has had a very long life. On the other hand, those who have lived in very short time intervals are useful for dating because they represent a precise time. These fossils are called stratigraphic fossils.

To qualify as a stratigraphic fossil, a species must:

    • have had a large geographic extension (allowing correlations),

    • have existed for a short time at the geological time scale,

    • have been abundant (a necessary condition for finding fossils)

For example, ammonites are used to date Jurassic and Cretaceous rocks.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.