Many types of large reptiles died out, along with non avian dinosaurs, during the K-T mass extinction. These include pterosaurs, plesiosars, mosasaurs, and marine crocodylomorphs. Ammonites, a highly successful group of molluscs, became extinct. On land, scientists believe that no species larger than a housecat survived.
By the way they look, (their bone structure, body weight) and DNA too.
The background rate of extinction is much smaller than those that occur during a mass extinction. For example, carnotaurus sastrei went extinct during the mid-Cretaceous, when only a handful of dinosaurs went extinct. On the other hand, 65 million years ago, all dinosaurs went extinct during the K/T mass extinction event.
The higher the biodiversity, the higher the number of species, and the lower the rate of extinction. A decrease in biodiversity means a single species will become extinct and this will have a negative impact on other organisms for all organisms in an ecosystem are connected.
many river dolpinhs face extinction(in Asia one species was declared extinct) and so do many other species
The extinction rates of terrestrial and freshwater organisms varies per location. This is largely dependent on other growing and declining populations.
The answer to your question is: Extinction. If you are wondering what causes extinction, there are nearly as many answers to that question as there are extinct species. Examples: Pandemics Cometary or asteroidal impacts Competition Ecological imbalance And thousands of other causes.
The Allosaurus became extinct during the Late Jurassic period, approximately 150 million years ago. The exact cause of its extinction is still debated among scientists, but some theories suggest that changes in climate, competition with other predators, and possibly even disease could have played a role in the decline of the Allosaurus population.
The process in which groups of organisms die out is called extinction. Extinction occurs when a particular species cannot adapt to changing environmental conditions or faces competition from other species, leading to their eventual disappearance.
Placoderms appeared in the fossil register during the Silurian period, and all placoderms (including the nightmarish Dunkleosteus terrelli) went extinct on the Late Devonian extinction.On the Carboniferous period there were already no placoderm fishes in the oceans.This Paleozoic era extinction(s) is not yet fully understood.However, the extinction of many marine life families in the Devonian/Carboniferous mass extinction, during the Frasnian/Famennian stages and specially the Kellwasser event, was due to the widespread oceanic anoxia.Few other reliable paleontologic data is known.
A hole in the ozone is a big threat. It can cause humans and other organisms to extinct.
Organisms that are not well adapted may struggle to survive and reproduce in their environment. This can result in low fitness, decreased reproductive success, and ultimately may lead to population decline or extinction. Factors that contribute to poor adaptation can include changes in the environment or competition from other species.
Pterodactyls died out along with the dinosaurs and many other animal and plant species during the K-T extinction event. It is believed that an asteroid, along with other environmental changes, struck the Earth and contributed to the mass extinction. Dinosaurs, pterosaurs, and many marine reptiles were not able to cope, so they went extinct.