Paleo 201 midterm

fossils

something that has been dug up from out of the ground

adaptations

features that serve particular functions and are results of evolution. they help animals to survive by serving major functions

dinosaurs

• come in all different shapes and sizes

• the largest animal to exist

• members of the vertebrata

giraffatitan

the largest in height

diplodocus

the largest in length

argentinosaurus

largest in weight

bones

• act like support columns

• provide rigid framework for muscle attachment

• provide protection

• major components of horns and others

• mineral reserves

air sacs

more air inside the body compared to mammals

vertebrata

• presence of skull and vertebrae

• interlocks with the vertebral column

• the skulls has orbits, nares, and fenestrae

supratemporal fenestra

holes on the top of the skull

laterotemporal fenestra

lateral sides of the skull; provides room for large jaw muscles

antorbital fenestra

by the nasal and had the air sacs

oder of vertebrae

1. Cervical: in the neck, openings for blood and nerve channels and support the weight of the head.

2. Dorsal: in the back, tall spinous processes and large rib articulation surfaces.

3. Sacral: in the hips, solid anchors for powerful leg muscles, fused with each other (sacrum).

4. Caudal: in the tail, chevrons are there which protect a large blood and nerve channel to support the tail muscles.

scapula

shoulder blade, the largest bone in each side of the pectoral girdle

acetabulum

hip socket where the femur inserts - formed by the ilium, ischium, and pubis

vertebral processes

• provide attachment for muscles and sometimes provide articulation surfaces for ribs

• two types:

  • transverse processes: extend from the lateral sides

  • spinous processes: extend upwards from the neural arch

tetrapods

animals that evolved from an ancient ancestor with four feet and four limbs

Saurichians

• lizard shape hip pelvis

• the ischium and pubis face different ways - pubis is downward to the ribcage

• sauropods, theropod, prosauropod

sauropod

• long neck dinosaurs (longest to live)

• walked on all legs

• herbivores

• small heads

• vertebrae is filled with complex air sacs

• teeth are simple and peg like

theropod

• carnivores, herbivores, and omnivores

• big and small dinosaurs

• walked on hind legs (bipedal)

• three clawed fingers

• mostly carnivores with blade-like teeth and hooked claws.

prosauropod

• early group of plant eating dinosaurs

• much smaller than other sauropods

• small heads and long necks

• replaced by herbivorous dinosaurs

ornithischian

• bird shape pelvis - pubic bone that points backwards

• the predentary is a distinguishing factor

• herbivores - predentary bone, flat teeth, backward hip bone for larger digestive tract

• hadrosaur, ornithopod, ceretopsia, pachycephalosauria

hadrosaur

• complex dentitions - dental batteries

• broad and large beak

• “duck billed dinosaurs”

ornithopod

• bipedal all the time OR when running only

• spikey thumb

• no armnor

ceratopsia

• large horns over eyes and nose

• narrow skull that expands in the rear

• parrot beak

• banks of teeth (dental battery)

• bony

pachycephalosauria

• high domed skull but not intelligent - used to recognize each other

• legs are not long so they don’t move fast

• bipedal with short arms

• armored skulls

• sharp comical teeth in the front of their mouths

• and leaf shaped in the rear - could be omnivores

stegosauria

• walked on all four legs (front legs were shorter)

• long and low skull

• plates, spikes, and osteoderms across the back

• not fast runners but could pivot quickly

ankylosauria

• walked on all four legs

• blocky skulls

• very round

• tail glove with huge osteoderms

• heavily armored

• short legs

• wide ribcages

mummified dinosaurs

• skeletons with a lot of skin with the bones - “in the flesh”

• the first one found was a hadrosaur

• discovered that dinosaurs are scaly, but integuments are difficult to know

keratin

fibrous structural protein that is flexible but relatively durable, major component of the hair, scales, and feathers

melanosomes

• organelles containing colour

• black and grey - long and narrow melanosomes

• brown and reds - short and wide melanosomes

• white - no melanosomes

• iridescence or glossiness - narrow melanosomes aligned in the same direction

coprolite

fossilized fecal remains

taphonomy

• what happens between the time of death of an animal and when someone digs up the fossils.

• can learned about environments, cause of death, what animals were doing until their death

best fossilization locations

wet environments and low elevations

bloat and float

when dinosaurs die, they can swell with the putrid gasses which allows them to float and easily be taken by flowing water

sedimentary rock

• a good place for animals to fossilize

• a type of rock that forms from particles of other rocks that have been cemented together

igneous rock

rocks that form from cooling and solidification of magma or lava

metamorphic rock

a type of rock that forms through the transformation of other rocks under extreme heat and pressure

sandstone

rocks made out of sand

mudstone

rocks made out of mud, quiet water environments

coal

fossilized and compressed plants

limestone

sandstone, mudstone, and coal ; marine area

fluvial deposits

river and stream deposists

lacustrine deposits

lake deposits; these have better chances of preserving soft tissues due to little water movement

aeolian/wind based deposits

desert area

long-bone alignment

the bones will be configured in the same direction of the flow of water

preservation styles

• ways in which an organism can be preserved as a fossil

• permineralization and replacement

permineralization

fossilization processes in which minerals are carried by water into internal spaces of an organism and then solidify

replacement

when the original shell or bone dissolves away and is replaced by a different mineral

plastic deformation

taphonomic alteration to the shape of a fossil that does not result in fracture or breakage; usually the result of prolonged exposure to pressure.

bone bed

accumulation of bones from many different animals. this represents bones that washed downstream and dropped in a body of water. it normally shows animals that lived in the area of 100s of 1000s of years

quarry

an open pit where a bone bed is exposed

overburden

the earthen debris that overlays a bone bed. use large indelicate tools

carnivore

• have sharp pointed teeth

• sharp claws for eating meals

• serrations

herbivore

* flat rigid teeth for grinding vegetable matter

omnivore

sharp and flat teeth for meat and plants

insectivore

• animals that eat insects

• weak jaws and reduced teeth

• long spade-shape claws for digging

piscivore

• animals that only eat fish

• they don’t need teeth for ripping prey

• tall, sharp, conical teeth

• elongated jaws that move fast and hold on to slippery fish

frugivores

only eat fruit

durophagy

• eating behaviour

• have sharp teeth for puncturing and ripping flesh

• have strong rounded teeth that enable them to crack bones

• powerful jaws

teeth

• dinosaurs are always growing new teeth - they can be layered

• a large hadrosaur can have 1000 teeth at a time

• herbivores replace their teeth often (they wear down)

• shed teeth are common fossils

dental battery

• dense arrangement of teeth found in the jaws of hadrosaurs and ceratopsians.

• helps with the challenge of cellulose

• animals with these replace teeth rapidly, chewing is uneven

• HADROSAURS: dental batteries are angled downwards, but still mostly horizontal. They moved their jaw forward, backward, and side-to-side. They are inset in the jaw.

• CERATOPSIANS: slid together like scissors blades, with the opposing lateral sides of teeth doing most of the grinding. They are inset in the jaw.

resorption

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

dromaeosaurs

• group of theropods

• enlarged sickle-shaped claws on each foot

• stiffened tails

• retractable claws and walked on two legs

• lived in the cretaceous period

gastric mill

muscular pouch in the digestive tract near the stomach that holds gastroliths. as the muscles rub the stone against each other, food passing through the mill is ground up, performing the same function as teeth

spinosaurs

group that resembles crocodiles which are thought to be piscivores

alvarezsaurs

group of theropods with short limbs and compact hands which are insectivores

tyrannosaurs

group of theropods that have reduced front limbs and robust skulls. their teeth are serrated and are adapted for puncturing and cutting flesh. they have a powerful bite

scavenging

refers to the consumption of an already dead animal by a carnivore that did not play a part in killing it.

cololites

fossil gut contents

erect stance

• legs directly underneath; mammals and birds

• more efficient and take less energy

• passively support the weight with no strain

• helps with speed

sprawling

• legs out to the side of the body; lizards, turtles

• these animals stay on their belly a lot

comparative morphology

• comparing shapes from one animal to another

• this helps relating back to dinosaurs

• the study of physical feature across various species

graviportal

• supports heavy loads

• thick and column like

• heavier loads but not fast

• large feet

• joints bend as little as possible

cursorial

• adapted for running

• longer lower leg bones

• walk on toes or toe nails (horses)

• not meant to have a lot of weight

• limbs elongate for faster locomotion

• digitigrade, unguligrade, plantigrade

digitigrade

stand on their toes

unguligrade

stand on their nails that have been modified to hoofs

plantigrade

stand on toes, the flats of the feet, and heels

muscle reconstruction

show movements of animals and what is most efficient

caudofemoralis

• hind limb retractor muscle positioned at the tail base

• flex the tail laterally to its corresponding side when the pelvic limb is bearing weight

• shows that the T rex was faster than expected

• when the lever arm is short, it takes more energy for movement

• large theropods and hadrosaurs

trochanter

femora of crocodiles and birds, where the caudofemoralis muscle-ligament attaches

bipedal

• walk on two legs

• advantages: fast runner, flight, and grasping prey

quadruped

walks on four legs

facultative biped

capable of walking on all four or just two legs

obligate bipeds

• no choice but to walk in two legs

• ancestor of all dinosaurs

• sauropods, stegosaurs, ankylosaurs

ichnofossil

any trace or track left by an animal; biologic activity

footprints

• Mud can dry out with footprints on it allowing it to harden, then more mud hardens on top to preserve it.

• shallow footprints show that they walked on all four legs

• when footprints are spread out, it can be determined that they were running

• the size of the animal can be determined by the size of the footprints

endotherm

• animals that generate their own internal heat and control their body heat metabolically

• lots of energy used

• advantages: survive in cold climates, always ready for action, and can be out and about

ectotherm

animals that do not generate their own heat and must regulate their temperature through behaviour

histology

• the technique of slicing samples of bones into very thin sections, such that the internal structure of the bone can be observed under magnification

• shows that bones grew fast

osteons

bone cells

cube-square law

• A mathematical principle that explains the discrepancy in the relative change of surface area and volume as an object grows or shrinks

• as the size of an object increases its volume increase by a factor of three, while its surface area increase by only a factor of two

• large body volume and small surface area = internal temperature is less affected by the external environment.

gigantothermic

animals so large their internal temperature is unaffected by the surrounding environment

amniotic eggs

• they have an amniotic sac

• don’t have to live in the water - shells

• hard shell advantages: mom can live far from the water, they are permeable

new born dinosaurs

• less prominent facial extrusions

• larger eyes

• smaller sizes

• shorter relative limb strength

• larger head.

• When growing into adulthood, the limbs grow much faster than the rest of their bodies.

Lines of Arrested Growth

• growth rings inside of the bones

• determines how long it took dinosaurs to grow to a particular size and what speed a dinosaur grew

high vascularity

bones of young dinosaurs with many blood vessels; texture is called lamellar bone

remodeling

bone cells replaced by newer bone cells

external fundamental system (EFS)

• spaced series of LAGs when growth slows or stops

• indicates the dinosaur is skeletally mature

ontogenetic changes

• anatomical changes that occur during an individual’s life

• newborns can look much different than the adult form

• Horned dinosaurs didn’t grow horns until they were old enough to use them.