Simplify the following text for a Grade 14 native English-speaking person.
Original: Knight often restored extinct mammals , birds and marine reptiles in very dynamic action poses , but his depictions of large dinosaurs as ponderous swamp-dwellers destined for extinction reflected more traditional concepts ( Paul , 1996 ) .
Simplified: Knight often restored extinct mammals , birds and marine reptiles in action poses , but his depictions of large dinosaurs as ponderous swamp-dwellers destined for extinction reflected more traditional concepts .