Comparative Morphology (Skulls & Muscles) Flashcards
For sight, what are some characteristics that are adapted by carnivores ?
Eye that are more forward facing, which provides binocular vision. Allows for accurate depth perception.
For sight, what are some characteristics that are adapted by herbivores ?
Eyes are located at the side of the skull, to provide the animal with a broader field of vision. To aid them to monitor their surroundings while grazing.
For smell what are some characteristics adapted by a carnivore (in their skull)?
They have a developed olfactory region in their brains and possess a complexed nasal structure with a high number of olfactory receptor cells. Their snouts are long and slender to help channel the scents to the olfactory regions and the nasal bone is usually thick for a stronger bite force.
For hearing what adaptations are found in the skull of carnivores ?
Their ears are pointed forward and positioned higher for better sound localisation and have enlarged auditory bullae which enhances sensitivity of sound.
For Smell, what are some adaptations in Herbivores and their skulls?
Have a good sense of smell, but not compared to carnivores. Nasal structures are less elongated and less specialised. They have Broder snouts suited for feeding on vegetation and thinner nasal bones.
For Hearing in Herbivores what are some characteristics they possess?
Herbivores have ears that are on the side of their skulls so that they are able to have a broader sense of perception as they feed. Some herbivores have a smaller auditory bullae compared to carnivores as they do not need that level of sensitivity to locate prey.
What are some prominent features in a carnivores skull when identifying one?
Carnivores usually have a sagittal crest located at the centre of the parietal bone, this crest is one of the distinctive features for carnivores and where the temporalis muscles would attach to for stronger bite force. Other features like have a wide zygomatic arch would imply that there are more muscles attached to the jaw indicating more bite force.
If the orbit were to be forward facing, it would also imply that this animal is a carnivore.
They would also have a sophisticated nasal structure where the olfactory region of the nasal structure would have numerous infolding bones to provide a larger surface area. The nasal structures tend to be thick and more elongated to aid in bite force and heighten sense of smell.
In the upper jaw, there is the premaxilla and the maxilla. The premaxilla, holding a set of canines and 4 incisors and at the maxilla, there are 4 premolars (1 being the carnassial) and 2 molars.
In the mandible, is 1 canine and 3 incisors, 4 premolar and 2 molars (1 being the carnassial)
What are some characteristics for hearing, smell and sight for Omnivores ?
Omnivores for hearing they have a versatile ears that can be directed forward of side facing.
For sight, they have a combination between forward facing and sightly lateral eyes which provides a balance between binocular vision and a wider field of view for overall situational awareness.
for smell, they have a diverse range of nasal structures, allowing them to detect both plant and animal food sources.
What are some features that can be seen in a herbivores skull ?
Herbivores have orbits that are usually side facing, and would have zygomatic arches that are thinner and not as distinct as carnivores. same for the ear canal which is more side facing.
Herbivores tend to have a more perpendicular condyle in relation to the lower tooth row and maybe have a tall ascending ramus.
Their teeth are flat crowned and have horizontal ridges which allow for grinding.
on the Maxilla there are 5 molars and on the mandible there are 5 molars an d4 incisors.
What are the 4 main muscles involved for biting and lifting of the mandible ?
The Temporalis muscle, the masseter, the larger medial pterygoid muscle and the lateral pterygoid muscle
What is the role of the temporalis muscle?
The temporalis muscle is a fan shaped muscle that is attached to the outside of the brain box spreading to just behind the eye to the the posterior and the dorsal ridges of the skull surface. It is inserted on the coronoid process of the dentary.
What is the role of the masseter muscle ?
The masseter muscle originates from the zygomatic bone. The larger superficial masseter bone is inserted from the ramus and angle of the dentary bone. It is the primary muscle for elevating the jaw while during biting
The smaller deep masseter muscle is inserted from the posterior ramus and runs along the surface of the lateral pterygoid muscle.
What does the larger medial pterygoid muscle do ?
The larger medial pterygoid muscle originated from the ventrolateral projection of the brain box and is inserted on the ramus at an angle.
What does the lateral pterygoid muscle do?
The lateral pterygoid muscle, originates from the dorsal to the internal pterygoid muscle on the wing of the sphenoid bone of the brain box and is inserted on the condyle.
