Lesson 3: Eating Flashcards
why is knowing about a dinosaur’s diet important?
A Dinosaurs diet can help us understand where it was on the food chain and how it lived in the ecosystem
what are the 9 types of eaters?
herbivores, carnivores, omnivores, Serrations , Frugivores, Piscivorous, Insectivores, Durophagy, Scavengers
what type of teeth do herbivores have?
Tend to have thin, ridged or “leaf shaped” teeth for shearing and broad, flat teeth for grinding and for herbivores that browse high in trees, but cannot climb, have long legs and necks
what type of teeth do carnivores have?
Tend to have sharp pointed teeth for piercing, and sharp hooked claws for holding onto struggling prey
what are serrations and what type of eater has them?
Are small sharp bumps on a tooth that are arranged in a line that usually runs from the tip to the base of the tooth. common in carnivores
what is a frugivores
A type of herbivore
Parrots
Eat primarily fruit
Beak of a parrot is sharp and hooked
what is a piscivorous
Are specialized carnivores that primarily eat fish
Piscivores tend to have tall, sharp, conical teeth that usually lack serrations. These adaptations make piscivore teeth good at spearing and holding onto slippery fish. Have elongates jaws that can reach far and snap fast
Teeth are usually tall and conical which are good for spearing and holding on to slipper fish
Have procumbent dentition which means that the teeth in the front of the mouth point forward at an angle rather than straight up or down.
This allows front tips of the jaws to be used to impale fish like a harpoon
what are insectivores
Specialized carnivores that primarily eat insects
But many insects are soft bodied and can be swallowed whole, without being chewed, so many insectivores have weak jaws and reduced teeth
what are Durophagy
Some carnivores, like hyenas, Tasmanian devils, and alligators, have sharp teeth for puncturing and ripping flesh but also have strong rounded molar teeth that enable them to crack bones
Extremely powerful jaws
what are omnivores
Are animals that eat significant amounts of both meat and plants
Some shaped like those of herbivores and others like those of carnivores
what is resorption of teeth?
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. When bones and teeth are broken down while an animal is alive and the minerals are transferred back into the blood
what is cellulose and how do animals deal with it?
It makes plants a difficult source of food. Animals cannot digest cellulose on their own. dental batteries and Gastroliths
what are dental batteries
Some herbivorous dinosaur groups are one way of dealing with the challenge of cellulose. Dental batteries are arrangements of densely packed teeth that collectively form a single, large chewing surface, and two groups of dinosaurs evolved dental batteries: hadrosaurs and ceratopsians
what are gastroliths and why are they important
Stones inside the ribcage that help digest food in oviraptorosaur and ornithomimids. It helps toothless animals to “chew” their food
Many modern birds, including chickens, have a gastric mill, which they fill by swallowing pebbles that they pick up from the ground. Small masses of little stones found in rib cages of some herbivorous dinosaurs. Form part of the ‘gastric mill’ that helps some dinosaurs and birds grind up plant matter
what is a Dromaeosaurs
A group of theropods with an enlarged and sickle-shaped claw on each foot and stiffened tails; lived during the Cretaceous period; examples: Velociraptor, Utahraptor, Deinonychus. Stomach content that can provide information on diet
what is a Spinosaurus?
Are a group of theropods with skulls that strongly resemble those of crocodiles
Piscivores
what’s an Alvarezsaurus
Short front limbs and compact hands
Insectivores
Have reduced teeth and short, but strong, front limbs
what type of teeth and jaw do Tyrannosaurs have
Have serrated edges
Have blunt tips and the attachment sites for jaw muscles indicate a capacity for tremendous biting force
Scavenging definition
Refers to the consumption of an already dead animal by a carnivore that did not play a part in killing it
what are Cololites
Fossil gut contents found in the colon
Can help figure out a dinosaurs diet
what are Coprolites
fossilized poop
what are Durophagy?
The eating behaviour of animals adapted to crush bones
what are dentine
Hard tissue that helps to form teeth
what is the study of ontogeny
The development of an individual Growth Why is it important? Vast ontogenetic changes may lead to ecological changes Study gave evolutionary implications
agonism definition
Certain forms of conflict
Why is it important?
To identify play fighting between juvenile dinosaurs vs. embedded tooth in adults
what is Paedomorphism?
Retention of juvenile characteristics into adulthood
what is Evolutionary encapsulation
The evolutionary history of an organism is reflected in its ontogeny
what is Evolutionary developmental biology
Evolution occurs when ontogeny is altered
Extant embryos: the evolutionary changes in genes and proteins that control the formation or morphologies at different ontogenetic stages
how many ontogenetic stages? and what are they
Macroscale and microscale
what is macroscale and what is its importance
Epiphyseal fusion
open/close sutures
Surface texture
Size
It is possible to determine the age of death of an animal by examining degeneration of a certain particular surface where bones meet together
Suture fusion, especially in skull material and vertebrae
Bone texture
Texture of periosteal (surface) bone can indicate relative age
Juveniles have striated bone texture vs smooth adult surface bones
what is microscale and what is its importance
Histology
Amprino’s rule
Lamellar vs fibrolamellar
Juvenile vs adult
what is Amprino’s rule
Difference in bone tissue types reflect variations in bone deposition rates
Slow rate of bone formation: lamellar bone matrix, ordered arrangement of collagen fibres and osteocytes
Fast rate of bone formations: fibrolamellar bone tissue - collagen fibres more haphazardly arrange (woven bone)
dinosaur growth rate
Most dinosaurs experience extremely rapid growth rates
All but the smallest display highly vascularized fibro-lamellar bone texture at some stage
Fibrolamellar bone through ontogeny
Original woven bone matrix; entrapped blood vessels create porous spaces
Increases age, lamellar bone fills spaces; primary osteons
Lamellar bone eventually encircles primary osteons: secondary osteons
Juvenile vs adult
Juvenile: lots of woven (fibrolamellar) bone and LOTS OF VASCULARISATION
Adult: more lamellar bone, LESS VASCULARISATION and primary/secondary osteons
aging in a dinosaur
Once thought to be continuous, in concurrence with some modern reptiles
1. Lines of arrested growth (LAGS)
Periods of reduced or halted growth; annual; only means to tell actual age of dinosaurs
2. External fundamental systems
Series of tightly packed growth lines near external surface
Predicting growth rates
Allows us to plot growth rates by plotting estimates of body size against ontogenetic age (LAG count)
What have histological studies taught us?
All dinosaurs grew more rapidly than reptiles of a similar size nowadays
Larger dinosaurs grew super fast
Exceptions
Gigantism: sauropods rarely display LAGs
More often we find “polish lines” which are smaller annual markers of reduced growth
“Plexiform bone”: layers of similar thickness separated by small layers of highly vascularised tissue
Extremely rapid, nearly continuous growth
Exceptions
Small theropods: slow growing dinosaurs with ‘parallel-fibred’ bone tissue
Parallel-fibred bone tissue is one of the slowest types of bone tissue
Von Ebner line counts
Incremental lines of short period growth
Dentine sporadically deposited natural biorhythms
Shown to represent daily dentine deposits
Von Ebner line counts can be used to estimate tooth growth
Compared to other Tyrannosaurids e.g. Albertosaurus
Allometry of relative growth
“The study of size and its consequences”
Differences in proportional growth (specific parts growth)
Huxley’s equation of simple
Equation
Y = bXa
X = overall size of organism
Y = any part of organism
a = allometric coefficient
The size of any part may be expressed as an exponential of another…which means?
Positive allometry
a>1 : Y has faster growth than X
In caribou (antlers grow faster than the rest of the body
Positive allometry has been denoted as non isometric growth
Negative allometry
a<1 : Y has slower rate than X
Human cranium grows extremely quickly as a baby, but as you get older it stops
Modern analogy
Parallel them with Cassowaries Hatchlings lack any trace of ‘casque’ Negatively allometric <80% full size Strong positive allometry > 80% Crets are used in mating Amplifiers for females Visual display for males
4 Problems with dinosaur ontogeny
- Lack of complete sequences
- Dinosaurs grow differently to everything else
- Dinosaurs grow differently to other dinosaurs
- Particular features on dinosaurs can grow at different rates to the rest
Juveniles might not look like adults
what are 3 indicators of ontogeny
Macroscale - fusion, bone texture, size
Microscale - amprino’s rule, fibrolamellar bone vs lamellar, vascularised (juvenile) vs remodelled (adult)
Dinosaur growth rates, LAGs and Body Mass
which two types of dinosaurs have dental batteries
hadrosaurs and ceratopsians
what type of teeth do piscivorous have
conical teeth
which of the following is the best evidence that a dinosaur chewed its food
dental batteries
which of the following is a food-processing adaptation found in many modern herbivorous birds?
stone-filled gastric mill
Which of the following groups of dinosaurs is thought to have been primarily insectivorous?
Alvarezsaurus
