Mesozoic plants and invertebrates (final exam) Flashcards
What was the impact of continental distribution in the Mesozoic
- affected ocean circulation and climate
- greatly affected organismal evolution
> South America, India, and Australia became separated from other continents > animals on these continents evolved independently which increased diversity - diverse marine fauna in Mesozoic
What is the other name for The Mesozoic and why?
aka the Age of Reptiles
- bc dinosaurs and other reptiles were the dominant vertebrates
What are the main points/summary of the evolution/state of animals and plants in the Mesozoic
- marine bivalves, gastropods, and cephalopods rebounded strongly after the end Permian mass extinction
- Angiosperms (flowing plants) evolved during the Mesozoic and soon dominated land ecosystems
- birds evolved in the Jurassic from theropod dinosaurs
- end Cretaceous mass extinction eliminated all non-avian dinosaurs and set the stage for mammal radiation
- mammals first evolved during the early Mesozoic (Triassic) > remained relatively small until the Cenozoic
How did marine invertebrates and reefs recover from the end-Permian mass extinction and into the Mesozoic? (what was dominant)
- marine invertebrates repopulated seas quickly following end-permian mass extinction
- Cephalopods were dominant (ex. Ammonites)
- Reefs did not recover until mid-Triassic
- rudists (bivalves) were main reef builders > oil reservoirs today
- Scleractinian corals (modern corals) diversified
What happened to brachiopods and bivalves in the Mesozoic?
Brachiopods never fully recovered from the end-permian extinction
> replaced by bivalves and gastropods as dominant epifaunal and infaunal benthic animals, more burrowing
Explain the evolution of Ammonites in the Mesozoic
- their shells evolved greatly from Jurassic to Cretaceous
- straight shells to bigger and tightly curled shells that were stronger and able to move more efficiently and be better hunters
Where can Coccoliths, Diatoms, and Dinoflagellates be found (marine phytoplankton)
These were the primary producers in the Mesozoic and Cenozoic oceans
Coccoliths > chalk
Diatoms and Dinoflagellates > harmful algal blooms
Dinoflagellates > bioluminescence
What is the broad group of marine phytoplankton that became abundant during the Jurassic and Cretaceous?
Planktonic Foraminifera (Coccoliths, Diatoms, and Dinoflagellates)
Explain the state of aquatic and semiaqautic vertebrates in the mesozoic
- a few labyrinthodont amphibians survived the Permian extinction
- frogs and salamanders diverged during the Late Permian or Early Triassic > evidence from the “Frogamander”
What were the dominating plants in the early Mesozoic?
Mesozoic dominated by seedless vascular plants and gymnosperms in Triassic and Jurassic (primary producers on land - flowering plants only happened later)
What are Angiosperms and when did they appear? Explain their evolution
- flowering plants
> have enclosed seeds and flowers - appeared in late jurassic to early cretaceous
- co-evolved with insects (took advantage of another evolutionary niche)
- largely replaced seedless vascular plants and gymnosperms
- have adapted to nearly every habitat (mountain, desert, marsh, swamp, oceans)
Briefly describe the vessel of fertilization for seedless vascular plants, Gymnosperms, and Angiospersm
Seedless vascular plants: fertilize in water
Gymnosperms: fertilize with seeds that develop in cones and pollinate by the wind
Angiosperms: seeds develop in fruits, pollination through wind, water, animals (fruits attract other organisms that eat them and then secrete out seeds)
- attracting pollinators and other organisms to aid in its reproduction process > diversifying fertilization making it easier for them to survive
What are Squamates?
*they are scaled reptiles (lizards)
- derived from Permian stem reptiles
- oldest squamate: Megachirella (middle traissic)
- modern lizards are very divers
- extinct squamates include mosasaurs (marine reptiles)
- sister group = Tuatara
When did snakes appear? What is the main interesting evolutionary trait with them
Appeared in the Cretaceous (evolved from lizards)
- the first snakes had legs
- front limbs lost first, then hind limbs
- now modern snakes have vestigial limbs
> have two little bones sticking out in their underbelly - believed to be remnants of their femur for hind legs
why did they lose their legs?
- maybe to make swimming or burrowing more efficient or just to make their body more streamlined for better movement
When did turtles evolve? What’s the debate about them
- first evolved in the Triassic
> first turtles had teeth & armour - Turtles’ evolution is quite unknown - fossils are quite rare
- debate over the origin of their shell > was it for terrestrial digging or for aquatic swimming?
When did crocodilians evolve? What did they evolve from? what are some of their characteristics?
Evolved in the early Triassic from Archosaurs
- Crocodiles were them most common freshwater predator by the Jurassic (were bigger in size and number than the dinos to begin with)
- high diversity in Mesozoic
- characteristics: bipedal (but some walked on 4 legs too), herbivores, small, large (huge size range), very diverse
What were the first flying reptiles? what did they evolve from? what are they NOT? and what are their characteristics?
*first flying vertebrates/reptiles were Pterosaurs
- evolved by end Triassic from Archosaurs
NOT - dinosaurs, ancestors of birds, or all big scary beasts
Characteristics:
- large size variation - 35cm wingspan to 10m wingspan
- large pterosaurs soared - wing membrane attached to elongated digit
- some covered in pyncofibres > similar to feather or hair, but not actually (unique to pterosaurs)
