FEEDING Flashcards
Why is feeding so important?
- the transition from ectothermy to endothermy has meant that energy requirements are much higher
Feeding begins in the (a) and mammals chew to create a food (b) which is swallowed.
a) mouth
b) bolus
Edentate means what? give examples of species that come under this?
This was likely to be an example of ___ evolution.
Without teeth
- includes xenartha (armadillos)
pholidota (pangolin) - convergent
What were the original triassic mammals like?
small and insectivores
Where is the zygomatic arch? What is it composed of?
junction of squamosal and fugal muscles
Where is angular process? Attachment for what muscle?
lower jaw, bottom right
- masseter
Where is the coronoid process? Interlocks with?
Top right of lower jaw
- locks into the zygomatic arch
Describe the two fossae
Temporal fossa on upper half of skull, attachment point
Massteric fossa, attachment point
The temporalis muscle originates at the (a) fossa and inserts into the (b) process. What is its function?
a) temporal
b) coronoid
- to pull the mandible upward and backward
The masseter muscle originates at the __ (a) ___ and inserts at both the (b) fossa and the (c) process. What is its function?
a) zygomatic arch
b) masseteric
c) angular
- to pull the mandible sideways and forward
Pterygoideus muscle originates at the (a) plates and inserts into what? (b)
c) Also what function does it have? Same as?
a) pterygoid
b) medial angular process
c) - mandible upwards and forwards
Why is the digastric muscle so weak?
because it functions to pull the jaw downwards but gravity does most of that work
Function of teeth
a) incisors
b) canines
c) premolars
d) molars
a) nipping and biting
b) crushing and grasping
c) slicing and shearing
d) grind, crush, chew
Why are occlusal surfaces important?
interlocking and interdigitation of teeth to maximise efficiency
Distinguish between non-mammalian and mammalian teeth repair/ replacement? Why is this important?
- non-mammals can simply replace teeth by creating them between digits/ teeth
- mammal species will erupt new teeth beneath the original ones in order to maintain occlusion
What is anisognathy?
the lower jaw is narrower and chewing is done on one size to improve occlusion
What qualities of a carnivore skull allow a larger temporalis muscle than masseter?
What does this allow carnivores to do?
- wide zygomatic arch
- large temporal fossa
- large coronoid process
- small angular process
- large occpital region
-put greater emphasis on closing and biting DOWNWARDS
Carnivores have a jaw joint that is (a) with the teeth line to allow the teeth to function like (b). Condyle of mandible allows the jaw to function like a (c).
a) level
b) scissors
c) hinge
In herbivores the jaw joint is (a) from the tooth row, and is set much (b). This allows what?
a) offset
b) higher
c) teeth to come into contact simultaneously in order to allow grinding
What qualities of a herbivore skull allow a large masseter muscle?
- narrow zygomatic arch
- large angular process
- small coronoid process
- small occipital region
- small temporal fossa
What is a diastema?
where canines have been lost allowing cropping at front and grinding at rear
The monotremata are an infraclass of the _(a)_theria.
proto
a) What is a cloaca?
b) what kind of posture to the monotremata have?
a) one orifice where the eggs, urine and faeces all exit through
b) sprawling
What do monotremata have instead of teeth as adults?
What does this mean for their skull?
- horny barbs or plates
- limited area for muscle attachment and weak jaw muscles
How are leathery beaks used to detect prey?
electromagnetic signals
The marsupials belong to the subclass __ and are also known as the __
theria
metatheria
What is interesting about the Marsupial post canines?What function do they have?
they are all the same size
- shearing function
Key differences in dental formula between metatheria and eutheria (ancestral forms)
- reduction in number of incisors
- more premolars
- 1 less molar
When did Marsupials thrive?
tertiary
Australidelphia is a good example of an ancestral (a) and its angular process is (b) and points (c)
marsupial
b) inflicted
c) inwards
The infraclass Eutipolyphyla feed on (a) using mainly incisors which are specialised to pierce (b).
a) invertebrates
b) chitin
How are the class Xenartha (anteaters) adapted for eating ants?
- huge reduction or loss of teeth
- little muscle attachment
- big salivary glands
- ripping forelimbs
How are fruit eaters such as (a) adapted for eating?
have sharp anterior teeth for piercing fruit
- rounded palate
- CHIROPTERA (bats)
Cetaceans are adapted in what sense?
baleen or increased teeth number for fish traps
What characteristics change in the transition from carnivore to omnivore?
- reduced sagital crest
- elongated post canine teeth
How have herbivores overcome teeth decay?
have very high crowned teeth
What is a carnivore gut like?
- short caecum
- short intestine
- short colon
Distinguish between ruminants and non-ruminants in herbivores
RUMINANTS - are foregut fermenters, 4 chambered stomach
NON-RUMINANTS - simple stomach but large ceacum
