Lesson 3: Eating Flashcards
How can paleontologists determine the diet of a dinosaur?
sometimes, a dinosaur skeleton includes fossils of its incompletely-digested last meal inside of its ribcage, but such fossil gut contents are rare
usually, to figure out a dinosaur’s diet, paleontologists must compare its feeding adaptations with those of modern animals whose diets can be directly observed
What are herbivores?
tend to have thin, ridged or “leaf-shaped” teeth for shearing and broad, flat teeth for grinding
modern birds lack teeth, but herbivorous birds tend to have short, triangular beaks
herbivores that browse high in trees, but cannot climb, have long legs and necks, like giraffes
What are carnivores?
tend to have sharp pointed teeth for piercing, and sharp hooked claws for holding onto struggling prey
raptorial birds have sharp and hooked beaks and claws
like modern carnivores, carnivorous dinosaurs usually have sharp teeth and hooked claws, and, like some carnivorous lizards, most also have teeth with serrated edges
What are serrations?
small sharp bumps on a tooth that are arranged in a line that usually runs from the tip to the base of the tooth
you can see serrations at work on the edge of a steak knife, and, just like the serrated knife edge, serrated tooth edges helped carnivorous dinosaur teeth to slice through flesh
What are frugivores?
eat primarily fruit
the beak of a parrot is sharp and hooked (not unlike the beak of a carnivorous bird), because it needs to rip and tear apart the peels and protective husks of large tropical fruits
What are piscivores?
specialized carnivores that primarily eat fish
tend to have tall, sharp, conical teeth that usually lack serrations
these adaptations make piscivore teeth good at spearing and holding onto slippery fish
also tend to have long jaws that are long, strait, and sharp at the tips
What are insectivores?
specialized carnivores that primarily eat insects
have sharp piercing teeth for puncturing the chitinous exoskeletons of insects
but many insects are soft bodied and can be swallowed whole, without being chewed, so many insectivores have weak jaws and reduced teeth
some have no teeth at all
have large spade-shaped claws and powerful, but short, limbs
What is durophagy?
some carnivores, like hyenas, Tasmanian devils, and alligators, have sharp teeth for puncturing and ripping flesh but also have strong rounded teeth that enable them to crack bones
durophagy also requires extremely powerful jaws
What are omnivores?
animals that eat significant amounts of both meat and plants
humans are a good example of an omnivore, as are pigs, most bears, rats, crows, and many turtles
tend to have either unspecialized beaks and teeth or a variety of teeth with different shapes (some shaped like those of herbivores and other like those of carnivores)
in your mouth, you have pointed canines, which have a shape characteristic of a carnivore, and you also have molars, which have a shape characteristic of a herbivore
What is resorption?
is the chemical process by which a dinosaur breaks down its own teeth and bones so that the minerals and nutrients that compose them can be reused
after a new tooth was ready to replace an old one, and after the old tooth’s root was reabsorbed, the top, or “crown”, of the old tooth could be shed
How did dinosaurs shed their teeth?
teeth that are ready to be shed still usually require a little help getting free from the little bit of gum that still surrounds their base
often loose teeth are shed while an animal is feeding
throughout their lives, dinosaurs were constantly in the process of replacing teeth
What can shed teeth tell us about the dinosaurs diet?
often, the skeletons of dinosaurs will be discovered with many shed teeth nearby
that tells us that the dinosaur to whom the shed teeth belong to was probably feeding on the other dinosaur’s carcass
What is a dental battery?
Dense arrangement of teeth found in the jaws of hadrosaurs and ceratopsians
two groups of dinosaurs evolved dental batteries: hadrosaurs and ceratopsians
because the individual teeth that make up dental batteries are small, and because chewing grinds teeth down quickly, dinosaurs with dental batteries replaced their teeth rapidly
in the skull, there can be over 1,000 teeth
surface is intricate, varied, and abrasive
What is cellulose?
Tough organic compound that forms plant cell walls
How do animals digest cellulose?
animals cannot digest cellulose on their own
animals need help from bacteria that live within their stomach and intestines
even with the help of bacteria, getting all the raw energy that a large animal needs to survive from plants is not easy
chewing food before sending it down to the digestive organs helps, because chewing breaks plants into smaller pieces that are easier for bacteria and digestive enzymes to envelope
