Lec 18 Mesozoic life Flashcards
test study
What is the Mesozoic Era known as
Age of Dinosaurs
What was rate of recovery from Permian extinction
slow for many groups
What was mollusc recovery after extinction
re-adapted to changed environment and became more diverse
what is adaptive radiation?
diversification and spreading out of a species into different habitats
What happened to ammonoids after extinction?
radiated from 2 to 100 genres
What happen to bivalves, gastropods, and sea urchings after permian extinction
increased in diversity during mesozoic
What modern sea animal appeared?
modern reef building corals
What happened to marine invertebrates in mesozoic
increased in complexity
What invertebrate formed reefs beginning in Jurassic?
rudist bivalves (extinct ring shaped 2 shell)
what are foraminifera?
single celled plankton with chalky shell
very important for photosynthesis
what are ammonites and beleminites?
2 important marine cephalopods that exploded in Mesozoic
what happened to the few remaining mammal like therapsids at the beginning of the triassic
the became extinct
What diapsid reptiles dominated the triassic
dinosaurs
what animal most common terrestrial vertebrate of triassic?
dinosaurs
What do lepidosaurs and archosaurs together make?
the diapsids reptiles
Lepidosaurs make up what animals
lizards , and snakes
What make up archosaurs?
- crocodyles 2. dinosaurs 3. birds 4. primitive diapsis
When did Archosaur group first appear?
Triassic
What four characteristics separate Archosaurs from other reptiles?
- upright feature (morphology) body shape/structure
- single skull opening
a. antorbital finestra (opening in front of eye) - finestra is a mandible ( open mouth)
- teeth compressed to the side
what single characteristic separated archosaurs?
a single skull opening in front of the eyes
What are the 5 orders of archosaurus? hint stop-c
- saurischia
- thechodonts
- ornithischia
- pterosaurs
- crocodylia
What is the only surviving archosaur group?
crocodylia
when did crocodylia first appear
late triassic
which group of archosaurs was primitive triassic?
thecodonts
which group was ancestor of dinosaur?
thecodont
When did first true mammal appear?
early triassic
Were mammals successful in mesozoic era?
no
Which group was warm blooded endotherms?
mammals
which group had advantage cold bloods (ectotherms) or warm bloods (endotherm) during mesozoic?
cold blooded
What advantage did cold blood ectotherm have during mesozoic?
Lower food requirement huge advantage
could sleep a lot not look for food
What 2 models proposed to explain rise of reptiles over mammals during mesozoic?
- climate change model
2. competition model
What is of mesozoic climate change model to explain reptile advantage over dinosaurs?
hot arid dry climate advantage to reptiles
Why hot dry climate advantage to reptiles and disadvantage to mammals?
- reptiles have lower food intake requirement
a. helps if food source drying up - scaly skin reduces water loss
What problem with climate change model of mesozoic
Red Beds … do not form in dry climate
what geologic formation found in mesozoic?
red beds
What advantage did reptiles have in competition model of mesozoic that explains lack of success of mammals?
Bipedal (walked on two legs upright) of reptiles that progressively developed huge advantage in hunting prey? so remaining therapsids eaten
when did bipedal posture develop in reptiles?
middle and late triassic
What problem of competition model for explaining why reptiles over took mammal like therapsids to extinction?
carnivores causing the extinction of their prey does not follow ecological model … (because the hunter would starve themselves
