Dinosaurs!

Question 1

What happened to life during the Pr-T extinction event?

Answer 1

-83% of all genera went extinct.
-Palaeozoic faunas never recovered but modern faunas do.
-Trilobites (100%), Crinoids (98%), Corals (96%) and Cephalopods (97%) went extinct.
-Bivalves flourished and replaced Brachiopods
-Organisms with calcareous skeletons and O2 sensitive were most impacted

Question 2

The Triassic

Answer 2

-Hot dry climate
-Temperate poles
-Formation of red sandstones and evaporites
-Pangaea

Question 3

What are Archosaurs and their two main lineages?

Answer 3

Archosaurs are a major group of diapsid reptiles that includes both extinct and extant species. The clade Archosauria is divided into two main lineages: Pseudosuchia (crocodylian-line archosaurs) and Avemetatarsalia (bird-line archosaurs)

Question 4

What are the 3 main clades of dinosaur?

Answer 4

Therapoda, Sauropoda and Ornithischia

Question 5

What were Mesozoic oceans like?

Answer 5

-Fauna bounced back quicker
-Inhabited by marine reptiles (Plesiosaurs/Ichthyosaurs), Cephalopods (Ammonoids)

Question 6

The Jurassic

Answer 6

-Pangaea began to split apart (Laurasia went north and Gondwana went south)
-Tethys ocean began to close
-More humid and sub tropical climate
-Gymnosperms diversify and spread
-Sauropods, Theropods and Pterosaurs diversify and spread

Question 7

Sauropods

Answer 7

-Long necks adapted to reach high places
-Originated in the Triassic but increased in size during the Jurassic

Question 8

Pterosaurs

Answer 8

-Flying reptiles not dinosaurs
-Hollow bones and fluffy proto-feathers
-Originated in the Triassic but diversified during the Jurassic
-Also got very large

Question 9

Therapods

Answer 9

-A diverse clade that includes birds
-3 toed limbs, feathers and mostly carnivorous
-Originated in the Triassic but diversified during the Jurassic

Question 10

Cretaceous

Answer 10

-Laurasia splits into North America and Eurasia
-Gondwana splits into South America, Africa, Antarctica, Australasia and India
-Atlantic ocean opens and the Tethys closes
-Warm climate and high sea levels (high sedimentary deposition in inland seas=limestones)
-Angiosperms and Ornithischians diversify and spread

Question 11

Ornithischians

Answer 11

-Beak like jaws
-Mainly herbivores and quadrupedal
-Some present during the Jurassic but peaked during the Cretaceous

Question 12

Avialae (Flying Therapods)

Answer 12

-Archaeopteryx and Confuciusornis
-True feathers and powered wings
-First diversified during the Cretaceous
-Transition between dinosaurs and modern birds

Question 13

Cretaceous-Palaeogene extinction event

Answer 13

-Large faunal change (end of the dinosaurs, ichthyosaurs, pterosaur and ammonoids)
-Caused by either an asteroid impact (Chicxulub crater ) or volcanism (Deccan Traps)
-Evidence for the asteroid is seen in the form of a global Iridium layer

Question 14

What engineering approaches are applied to fossil organisms to reconstruct anatomy, motion, behaviour?

Answer 14

DNA analysis, LiDAR (digitised models), CT scans (can see internal anatomy), Biomechanical digital modelling (reconstruction of movement), Comparative anatomy and Finite Element Analysis (FEA)

Question 15

How are modern scanning technologies used on soft tissues of fossil organisms?

Answer 15

-Synchrotron (a particle accelerator used to reconstruct cell nuclei)
-Melanosomes can be used to determine colours in preserved fossils

Question 16

Evaluate the limitations and ethical implications of genetic engineering and cloning approaches to de-extinction

Answer 16

-DNA doesn’t last long enough to survive and be used to reconstruct the deep past.
A US research group claimed to have extracted proteins from bone tissues (nobody else has replicated it).
-Sensitive to contamination.
-Oldest known reliable DNA is 800000 years old.