Fossils are the clues discovered by the paleontologists to know how the Earth’s history has changed over time. Fossil records give us information about the environment and ecosystem of the ancient groups of organisms that existed in the past. For example, the fossils of sea creatures and shells that are found in the mountains indicate that the landform was submerged in the sea during the past.

Relative age is the rock’s age compared to the other rocks. It can be similar when comparing your age to another person’s age. On the other hand, an absolute age refers to the numeric age of the rocks. To determine the absolute age of a rock, scientists use radioactive dating.

The geologic time scale is developed by the scientists to show the development of ancient life-forms and the geologic events which took place in the Earth’s history. Unlike the time scale that we use during the present time, the geological time scale uses relative and absolute dating to determine the timeline of the Earth’s history.

The physical environment and the biological forces are interdependent with one another. Any changes in the physical environment that are caused by geological forces, changing climates, collisions with comets, and other natural disturbances, affect the habitat of living organisms. In turn, the living organisms also cause the environmental conditions to change.

Radiometric dating is a method that is used by scientists to determine the absolute age of rocks and fossils. Since fossils are found in sedimentary rock layers that are deposited sequentially, the age of the fossils can be determined when the rock layers are dated.

If the fossil is within the dated rock layer, they have the same age. On the other hand, if the fossils are in a rock layer that is situated above the dated rock layer, the fossils are younger. If the fossils are in the rock layer below the dated rock layer, the fossils are older.

Due to continental drift, the geographical distribution of continental plates has changed. Some continents from the colder region have moved to the tropical region, and vice versa. This event led to changes in the distribution of ice and changes in the climate.

Moreover, the new placement of the plates created the Isthmus of Panama, which separated the Pacific ocean and the Atlantic ocean. This event caused the ocean’s circulation to change and created the Gulf Stream, which influences the global climate.

On the other hand, the collisions between continents have caused mountain ranges to form. This event affected the circulation of the atmosphere and triggered changes in the climate conditions on Earth.

Scientists used radiometric dating and other fossil evidence to look for the Tiktaalik fossils. They already had prior knowledge that the aquatic vertebrates first moved to land between 380 to 363 million years ago. They looked for sedimentary rock layers that match this age and started the search for the fossils from there.