10 Question Sci / Tech Quiz: Dinosaurs for Dummies | Paleontology

Answer: Palaeontologists

Palaeontology is the scientific study of prehistoric life which includes dinosaurs. The study of dinosaurs is traditionally achieved through examination of fossils. There are elements of the other specialisms involved in palaeontology. In fact, it borrows techniques from a multitude of sciences.

Geology could be said to be the study of the solids and liquids which make up the planet and the processes involved in getting there. Archaeology is more to do with man's historical impact on the planet and biology is the study of life and living organisms.

Answer: Mesozoic

The Mesozoic Era is broken down into three periods: the Triassic, Jurassic and Cretaceous. The era spans the period from around 252 million years ago to 66 million years ago and is sometimes known as the Age of Reptiles. The Paleozoic Era started around 541 millions years ago and immediately preceded the Mesozoic Era.

The Proterozoic Eon preceded the Paleozoic Era and the Cenozoic Era took over from the Mesozoic Era and runs to the present day.

Answer: Dinosaurs having an open hip socket

Dinosaurs were classified according to morphological (form and structure) features. Most dinosaurs (but not all) had a perforate acetabulum, or a hip socket with a hole on its inside surface. There are a surprising number of such features which separate dinosaurs from lizards.

There is still some debate as to whether dinosaurs were warm or cold-blooded. Modern reptiles (including lizards) are cold-blooded and mammals are warm-blooded with few exceptions. Dinosaurs certainly laid eggs and there is no evidence of dinosaur live-births. There are lizards which lay eggs and some which give birth to live young (viviparous).

Answer: Birds

It's a bit hard to imagine it, but a hummingbird has a dinosaur ancestor! Birds are believed to have evolved from the theropod (meaning 'beast feet') group of dinosaurs. These had features including air-filled bones and a wishbone. One or two theropods also had feathers.

Although crocodiles date from around 200 million years ago, they are not considered part of the dinosaur family. Crocodiles and dinosaurs share a common ancestor called the archosaur. When the archosaur family tree split, crocodiles were determined to be on a different branch from dinosaurs (and hence birds as descendants of dinosaurs).

In ancient times fish gave rise to amphibians which in turn led to reptiles. The lineage of modern day fish and amphibians bypassed dinosaurs.

Answer: Bird-like hips

One of the features of Ornithischia branch is that the pubis bone points to the rear of the animal, unlike in Saurischia animals, where it usually points to the front. Birds have a rearward-pointing pubis bone and it was this feature in birds that gave rise to the name. It has since been recognised that birds belong to the Saurischia branch and that some convergent evolution has taken place. In fact, the change to a rear-facing pubis bone occurred independently in three separate dinosaur groupings.

Answer: Avialae

Names are deceptive. Ornithomimosauria were theropod dinosaurs that looked a bit like ostriches hence the name 'ostrich mimic'. Ornithopoda were ornithischian dinosaurs with 'bird-like' feet. Pterosaurs were flying lizards in the order Pterosauria and were not dinosaurs.

Answer: Mammoths

Mammoths did not appear until about five million years ago, long after the demise of dinosaurs. Sharks have been in existence for around 340 million years, well before dinosaurs. Pterosaurs appeared twenty million years after the first dinosaurs and coexisted with dinosaurs until they both died out around 66 million years ago.

Answer: Yes

Surprising perhaps. The therapsids in the Triassic Period (250 - 200 million years ago) were the source of all mammals. The first mammals appeared around 220 million years ago and were small nocturnal insectivores, not surprising considering the dominance of dinosaurs at the time. Mammals filled the ecological niches vacated by dinosaurs and reptiles after the Cretaceous-Paleogene extinction event.

Marine mammals (such as whales, dolphins, seals and walruses) did not evolve until the Cenozoic period. They evolved from land mammals that returned to the sea.

Answer: Asteroid impact

All of the above answers may have contributed to dinosaur extinction; however it is the Chicxulub asteroid impact in the Yucatán Peninsula of Mexico which is considered to be the main factor. This affected the amount of sunlight reaching the Earth and changed the planet's ecology as a result.

The Cretaceous-Paleogene extinction event around 66 million years ago marks when the fossil record for dinosaurs disappears and dinosaurs (with the exception of the line giving us birds) became extinct. This ties in with the time of the impact.

The Deccan Traps in modern-day India are multiple basalt flood layers more than two kilometres deep and covering half a million square kilometres. They date from 68 million years ago to 65.5 million years ago and the volcanic activity associated with them affected atmospheric conditions and the composition of gases over a prolonged period.

Some argue that it was reduced volcanic activity towards the end of the Mesozoic Era that led to a rapid drop in atmospheric oxygen levels. This may have killed off the larger dinosaurs with their large demands for oxygen and which were unable to adapt. Competition from other species may have seen the demise of any survivors.

Answer: 75% or more

Marine fossil records point to a sudden (a millennium or less) rather than a gradual die off. It evidently affected all seas, oceans and land masses at the same time. Some species were decimated, others such as alligators and turtles did okay. When plants died off due to lack of sunlight, dependant herbivores followed. The large carnivores then died off. Omnivores and insectivores did better.

There have been four earlier extinction events. The worst, just over 252 million years ago, was the Permian-Triassic extinction event. This saw up to 96% of all marine species and 70% of all land vertebrate species perish. Unusually, insects also suffered badly in this one. What factors or combination of factors caused this extinction event is not clear. It took life on Earth about thirty million years to recover.