Lesson 1: Appearance and Anatomy Flashcards
What is paleontology?
the study of dinosaurs is a subdivision of the branch of science known as paleontology
it is the study of prehistoric life
a paleontologist’s knowledge of prehistoric life comes primarily from fossils
What is a fossil?
a fossil is any persevered evidence left behind by a prehistoric organism
means “dug up”
fossils are usually objects or structures found buried in ancient rock formations
dinosaur fossils include footprints, eggshells, coprolites (fossil poop), and in rare instances even skin and feather impressions
most dinosaur fossils are bones
Why are most fossils comprised of bones?
bones are partially made of minerals, which do noy decay as easily as flesh and other soft tissues
for this reason, bones have a much greater chance of being preserved as fossils
How can the sizes of dinosaurs be compared to modern animals?
although birds are the smallest dinosaurs that we know of, we still have many examples outside this group of living dinosaurs that were no larger than a house cat
Why is it hard to accurately estimate the weight of dinosaurs?
dinosaurs filled with air sacs like birds so it’s hard to estimate weight
What are adaptations?
traits that have evolved because they serve specific functions
How are bones adaptations that help an animal survive?
bones passively resist gravity and maintain an animal’s form
bones provide a ridged framework for muscle attachment
bones provide protection and can also be major components of horns and other robust weapons
bones store mineral reserves
What are vertebrates?
are animals that have two special kinds of skeletal adaptations: skulls and vertebrae
fish, amphibians, turtles, snakes, birds, and mammals are all examples of vertebrates
What are vertebrae?
structures made primarily of bone and cartilage that surround a portion of the spinal nerve cord
together, vertebrae interlock with each other in a series and form the vertebral column
What are invertebrates?
animals that lack vertebrae
include animals like insects, spiders, snails, squids, clams, jellyfish, and worms
Why are vertebrates more numerous when it comes to species of large animals?
this success is probably related to the vertebral column’s ability to passively support weight and to anchor enlarged muscles
What is the skull?
the skull is not a single bone
rather, the skull is made up of many bones that are tightly locked together
What are the upper and lower jaws in the skull?
the upper and lower jaws may contain teeth and/or include a beak, and they are critical for interpreting what a dinosaur was adapted to eat
What is the brain case?
is a hollow chamber formed by multiple skull bones that houses the brain
there are many small openings into the brain case
nerves pass through these opening and connect to the brain
the size and shape of a brain case can indicate the size and shape of the brain case can indicate the size and shape of the brain that it housed, and , therefore, can provide clues to a dinosaur’s mental capabilities
What are the nares openings in the skull?
the nares are the pair of openings for the nostrils
What are the orbit openings in the skull?
the orbits are the pair of openings for the eyes
What are the fenestrae openings in the skull?
additional skull openings
behind each orbit, dinosaurs have two fenestrae
What are the laterotemporal fenestrae in the skull?
fenestrae on the lateral sides of the skull
What are the supratemporal fenestrae in the skull?
fenestrae on the top of the skull
What is the function of the laterotemporal fenestrae and supratemporal fenestrae?
provide extra room for large jaw muscles
What are the antorbital fenestrae in the skull?
between each orbit and naris
the function is unclear
they may have simply been adaptations that made dinosaurs skulls lighter, or they may have also housed large sinus cavities that helped warm the air that dinosaurs breathed
What is the vertebral column?
is comprised of a series of interlocking vertebrae that begins with the first vertebra in the neck and ends with the last vertebra in the tail
What is the centrum?
spool or disk shaped body on the vertebra
What is the neural arch?
above the centrum
covers the neural canal
What is the neural canal?
is the opening in each vertebra through which the spinal nerves run
What are vertebral processes in the vertebra?
extending from the centrum or neural arch
provide attachment surfaces for muscles and sometimes provide articulation surfaces for ribs
What are transverse processes in the vertebra?
extend from the lateral sides of the vertebrae
What are spinous processes in the vertebra?
extends upwards from the neural arch
What are cervical vertebrae?
vertebrae in the neck
often have extra-large openings for blood and nerve channels and are adapted to support the weight of an animal’s head
What are dorsal vertebrae?
vertebrae in the back
dorsal vertebrae often have tall spinous processes and large rib articulation surfaces
What are sacral vertebrae?
vertebrae in the hips
because the pelvic bones in terrestrial vertebrates serve as solid anchors for powerful leg muscles, the pelvic bones are fused to the sacral vertebrae
What is the sacrum?
to further increase the strength of the hips, the sacral vertebrae are also fused with one another and form a single solid bone structures called the sacrum