Why did dinosaur species that lived in the sea also become extinct?
Whether it's continents drifting apart, volcanic eruptions, or the alleged massive meteorite impact, some species like birds and crocodiles have been proven to have survived on land. Now I wonder why nothing from that time survived in the water? That's where the effects on land should have been the least significant.
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Dinosaur species living in the sea have developed only in one subgroup, namely among birds (Aves). The penguins (Sphenisciformes), the birds that are best adapted to life in the sea today, have only developed after the chalk season. In the Cretaceous period there were similar bird forms which occupied the same ecological niches, for example the hesperotnithiformes. However, as they laid eggs, they remained limited to the coastal areas. All other dinosaurs were landlords, although some similar to the crocodiles led an amphibious way of life, e.g. Spinosaurus .
The great marine reptiles of the Cretaceous period, the Mosasaurians and the Pliosaurs, including the Plesiosaurs, were not dinosaurs. Mosasaurs were closely related to monitor lizards, so they belonged to the scale crimes (squamata), plesio and pliosaurs were not real squamats, but were close to them.
The impact of an asteroid was not supposedly, but proved. This demonstrates the high iridium concentration in the KT limit. The Chicxulub Crater could also be dated to Yucatán at an age of 66 million. years. In the meantime, by fossils in the site Tanis in the Hell Creek Formation in the USA it is even shown that the organisms found there (including a dinosaur) died as a result of the impact. In this site, last hour of chalk time preserved.
It wasn't like that. There were shapes in the sea that survived the mass extinction: sharks and rays, "bone fish", head feet, jellyfish – to name just a few examples.
This may be due to the immediate consequences of the Impact such as the global fires, earthquakes and tsunamis. However, the enrichment of the atmosphere with dust particles had an impact on the marine ecosystems as well as on terrestrial. In the oceans, too, all life depends on the biomass produced by the primary producers, namely the phytoplankone phytosynthesis. By darkening the sky, this system also collapsed into the marine ecosystems. Not only on land, there was hardly any food in the oceans. In addition, the impact resulted in rapid acidification of the oceans , which has affected both the global climate and the global carbon cycles.
have survived, on land as in the oceans, especially small, opportunistic species. So, species that came out with little and could exploit all that was found in sperm food. Why certain groups died, although they actually met these criteria, but others do not, is largely unclear. So died. the ammonites, while they survived quite similar utiloids.
Dinosaurs never lived in the sea. There were the great seafood but they weren't dinosaurs. They belonged to another group of sours.
The great marine reptiles had some problems with the impact. They got living young, they needed quite a lot of food. They could no longer immerse themselves in deeper regions such as sharks, other fish, jellyfish, head fins and other animals that have not breathed air. In the upper layers there was a stronger acidification and there was hardly any food. Living young people weren't good either. They couldn't survive. Sharks etc could survive because they could escape into deeper regions. Sharks have been there long before sea reptiles and dinosaurs, jellyfish and choppers as well as bone fish
Crocodiles still come out with very little food today. It's a meal a week. You can survive without problems for months without food. Some can even last longer time in a kind of rigidity over a year when it must be. Crocodiles take everything to prey if there is an opportunity.
They also lay eggs like turtles. Some eggs were able to survive the worst time of mass depletion also some adult animals.
The direct ancestors of the birds were quite small dinosaurs. Small animals were able to survive and develop on land rather than large because they needed less food. Certainly some eggs have survived with them.
Small species of mammals also did not survive many but enough that the mammals could rise.
The impact is completely unquestionably demonstrated by a variety of hard evidence.
Most Ichthyosaurs had already died in the early Cretaceous period, the remaining in the further course of the Cretaceous period. The cause is still unknown. Other marine reptiles have survived until the end of the Cretaceous period and have died together with the non-avian dinosaurs.
Otherwise, quite similar groups have died in the sea as on land. Nasty species that need the complete large amounts of food. These concerns all the marine lizards still present.
The reason is the same on land and in the sea. The short-term, extremely hard climate change after the meteorite impact and the simultaneous (induced), very strong re-ignition (the first phase was already before the impact) of the extreme river basalt outbreaks of the Deccan Trapps in India, has interrupted the food chains everywhere on Earth.
Survived on land and in the sea are species that can spend a long time with little food or are particularly opportunistic when choosing their food. After the environmental conditions had improved again, many ecological niches were free, which were newly occupied. That is why the mass extinction followed a true fireworks of evolution.
Yes, the Galapagos marine iguanas survived. And the turtle. But the other seasaurs have died. Nobody knows why. I personally think the Megalodon was eating them all. 🤣
It wasn't a dinosaur.
Neither Ichtyosaurs, Plesiosaurs, Pliosaurs nor Mosasaurs are closely related to "real" dinosaurs. The development lines have been separated long before.
It is believed that these Sea events have led to strong acidification, which is why marine organisms were also affected by extinction.