Mammal Teeth Jaws And Gut Flashcards
There is great evolution of heterodonty in mammals, what does this mean?
Evolution in different forms of teeth
What do possums not have in their skull and what does this allow
Tympanic bulla, allows them to have more teeth
What are bunodont (a type of cheek tooth) teeth?
Flattened for crushing in omnivores
Large roots
What are lophodont (type of cheek tooth) teeth?
Ridged grinding surfaces
Have dentine and enamel exposed leading to very uneven surface
What is the general structure of teeth?
Hard enamel surface, covering he dentine - main body of tooth
Pulp in centre
What are hypselodont teeth?
Open rooted for continual growth
Can be self sharpening because growing all the time
What are selenodont teeth?
Similar to lophodont, ridged for grinding
But crescent shaped
Deer have them
Why do deer have a gap between their front teeth and their back molars
Allows them to nip the grass with the front teeth and chew at the back
What are sectorial teeth?
Carnivores highly evolved molars, for slicing
Associated with tight jaw articulation
Cats and dogs have then
Who has the most adapted incisors?
Rodents
What are rodent incisors like
Open rooted, enamel only on front surface so self sharpening
What do rodents need to do to nip grass to eat?
Move their lower jaw forwardso that their incisors meet
Because when back teeth meet incisors don’t meet
What are the 2 types of herbivorous fermenters
Ruminants: foregut fermenters, food takes a long time to pass through because high level of digestion
Hind gut fermenters: pass food through much more quickly, but have less evolved stomachs
How do ruminants digest the cellulose so well?
They chew food twice, it is chewed, put into the reticulum, then chewed again
The stuff they chew the second time is called cud
How long does digestion take in ruminants
80 hours, they use about 60% of what they eat
