The Cretaceous period was an important time for the evolution of marine life. During this period, the Earth’s climate was warm and wet, leading to the formation of large inland seas in many parts of the world.
These inland seas were home to a wide variety of creatures, from fish and sharks to giant sea turtles and mosasaurs. In this article, we will explore the fascinating creatures that lived in the Cretaceous inland seas and how these creatures adapted to the changing climate. We will also look at how these inland seas have impacted the modern world.
How The Changing Climate Of The Cretaceous Period Impacted Inland Seas
The Cretaceous period (145.5 million to 65.5 million years ago) was the third and final period of the Mesozoic era, and it was characterized by a changing climate.
During the Cretaceous period, the global climate was much warmer than it is today and the majority of the planet was covered in shallow seas. Inland seas were particularly impacted by the changing climate of the Cretaceous period, as they had a direct relationship with global temperatures.
During the Early Cretaceous period (145.5 million to 99 million years ago), temperatures were generally warm, and the seas were shallow and widespread. This allowed for the growth of a wide variety of marine life in inland seas, including ammonites and belemnites. The warm climate also increased the level of carbon dioxide in the atmosphere, which led to higher levels of evaporation in inland seas.
This, in turn, caused the water levels in these inland seas to rise, creating larger areas of shallow water that provided ideal conditions for marine life. However, the climate of the Cretaceous period changed drastically during the Late Cretaceous period (99 million to 65.5 million years ago). Temperatures cooled, and the global sea level dropped drastically due to a decrease in carbon dioxide.
This decrease in temperature and sea level resulted in a decrease in the size of inland seas. As a result, the area of shallow water available for marine life to inhabit was reduced, and many species were unable to survive in the now harsher conditions. Overall, the changing climate of the Cretaceous period had a significant impact on inland seas.
As temperatures rose and carbon dioxide levels increased in the Early Cretaceous period, these inland seas became larger and provided ideal conditions for marine life. However, as temperatures cooled and carbon dioxide levels dropped in the Late Cretaceous period, the size of these inland seas decreased, and many marine species were unable to survive in the now harsher conditions.
How The Extinction Of The Dinosaurs Impacted Inland Seas
The extinction of the dinosaurs is one of the most studied and discussed events in the history of Earth. It was an event that reshaped the world and affected many aspects of the environment, including the inland seas. The extinction of the dinosaurs had a powerful impact on the inland seas due to the changes in the Earth’s climate and environment that ensued.
For instance, the removal of large herbivore species such as the dinosaurs meant that the vegetation in the inland seas changed. Without the presence of the large herbivores, the vegetation was no longer grazed, allowing it to grow in abundance, leading to an increase in the amount of oxygen in the water. The loss of the large herbivores also impacted the level of sediment that was entering the inland seas.
As the herbivores had previously grazed the vegetation, their absence meant that there was less erosion of the soils around the coastal areas. This led to a decrease in sediment load entering the inland seas, leading to a decrease in turbidity levels and an increase in water clarity. The extinction of the dinosaurs also changed the food web of the inland seas.
Without the large herbivores, the quantity of plant material available for smaller organisms to feed on decreased. This, in turn, led to a decrease in the abundance of small invertebrates and an increase in the abundance of larger organisms such as fish and aquatic mammals. The extinction of the dinosaurs had a profound impact on the environment of the inland seas.
It changed the level of vegetation, sediment, and food available to organisms living in the area, leading to a major reshaping of the ecosystem. This event had long-term implications on the environment of the inland seas and is still studied and discussed today.
The Diversity Of Flora And Fauna In Inland Seas During The Cretaceous Period
The Cretaceous Period was a major period of transition in terms of the evolution of flora and fauna on Earth. During this period the world was much warmer than it is today, due to higher levels of carbon dioxide in the atmosphere, and the climate was much more humid.
This allowed for the evolution of a wide variety of plants and animals in the world’s coastal and inland seas. In the Cretaceous period, the marine environment was home to a diverse array of species. Among these were a large variety of fish, sharks, turtles, crocodiles, and marine reptiles such as mosasaurs. Many invertebrates such as squid, ammonites, and nautiloids were present as well.
A variety of plankton, coral, and sponges were also found in the seas. The Cretaceous marine environment was also home to a wide variety of plants. Many of these plants were primitive forms of seaweeds and algae, such as green and red seaweeds. There were also primitive forms of flowering plants and grasses, as well as ferns.
These plants provided a food source for the marine animals, as well as oxygen for the waters. The diversity of flora and fauna in the inland seas during the Cretaceous period was remarkable. The warm, humid climate allowed for the evolution of a wide variety of species, and these species diversified over time.
The combination of this rich variety of species, along with the abundance of food sources and oxygen, provided a unique and productive environment for the evolution of life.