Lecture 13 Flashcards
What do different teeth have different types of?
. Enamel
. Surfaces to them which can aid the variety of dietary items
Which teeth are for cropping and tearing?
Incisors and canines
Which teeth are for crushing and shearing?
Premolars and molars
What order is Sorex (shrew) in?
Lipotyphla
What does it mean if teeth are deciduous?
Are replaced. Will decrease/ fall out (we the jaw gets bigger you have more space for more teeth
Describe the teeth of shrew
. Dental formula of 44
. All teeth but molars are deciduous
. Incisors are highly modified- unique derived character state= autapomorphy (one of the defining characteristics of the species
Describe the cheek tooth (molars) specialisation Bunodont common in omnivores. Give examples
On top they aren’t sharp . Quite rounded . Completely covered by enamel . Quite flat They are quite common of omnivores eating berries- crushing e.g. fruit bags (Megachiroptera), bears (Carnivora: Ursidae), pigs (Artiodactyla: Suidae), humans (primates: Hominoidea)
Describe the cheek tooth (molars) specialisation Lophodont, common in herbivores. Give example
. Ridged grinding surfaces . Dentine is exposed . Common in herbivores which gives them sharp edges to break down material . Cement, dentine, enamel all exposed E.g. Rhinoceros
Describe the cheek tooth (molar) specialisation Hyperodont. What is a disadvantage of this specialisation?
. Open-rooted for continuous growth (has not got a into the jaw)
. This means they will remain sharp so they don’t run out of tooth
. Disadvantage if there is a gap or you eat the wrong things then could end up with over growth
Describe the cheek tooth (molars) specialisation Polyphyodont and give an example
. Cycles of teeth
. Don’t erupt vertically
. (Evolution of arm race with plants as they put silica to prevent being eaten)
. Elephants: 6 replacements/ sets of teeth and once they are gone they will starve
Describe the evolution of cheek teeth (molars) in horses and why this has happened
. Progressive development of hypsodont (deep-rooted, well embedded in the jaw) cheek teeth since the late Tertiary (20mya)
. Seen as an evolutionary arms race involving grasses depositing progressively more silica in cell walls (as an anti-herbivore defence) so the horses need better teeth for processing that material
Describe the cheek tooth (molars) specialisation Selenodont. Give an example and how it works
. Crescent shaped molars
. Convergent with hypsodonty in functional anatomy
. E.g. deer- exposed dentine and enamel. Gap between the incisors and the cheek teeth, known as diastema, allows nipping and grabbing the grass at the front and chewing at the back with the material moved around by the animals tongue (ruminants)
Give the Latin name for fallow deer
Capreolus capreolus
What kind of cheek teeth do carnivores have? What are they associated with? Give examples
. Sectorial: slicing carnassials
. Associated with tight jaw articulation
E.g. cats and dogs (Carnivora: canidae and felidae)
Describe sectorial cheek teeth
Modification of the last premolar and the first molar, very sharp and lobed allowing the animal to slice and the animal to close the jaw tight
In Artiodactyla (e.g. Cervidae) how are the teeth different to other mammals? Example of species
Complete loss of upper incisors, replaced horny pad
E.g. fallow deer
Give the 4 incisor specialisations. Give species examples
. Gnawing: open rooted, enamel only on anterior surface, so self-sharpening: rats, mice, squirrels, beavers (Rodentia)
. Enamel on both sides: rabbits and hares (Lagomorpha)
. Different jaw articulation positions for gnawing and grinding
. The front teeth overhang so, they have to move the jaw, depending on whether they are gnawing or grinding, because they couldn’t chew plant material while nipping off the same time
Sweat does incisor specialisations dependent on?
The need for additional strength as to if they have enamel on both side
Teeth are not necessarily just for feeding, what else are they for?
Reproduction- sexual selection
What type of diet is acid digestion in the stomach effective for? Give examples
. Omnivores (mixed diet)
. Carnivorous
. E.g. Lipotyphla, Carnivora, Hominoidea
What do herbivores require so they can digest cellulose?
Intestinal symbionts
Which animals are foregut fermenters? Give examples
Ruminants (Artiodactyla) e.g. cows, sheep, goats, moose, common warthog
Why are all species of foregut fermenters large?
Slow system prone to inhibition by tannins; so all species are large
How do herbivores tackle digestion differently to carnivores?
. Spend a lot of time chewing
. Material will not pass into the acid stomach until it is well broken down, the starch and silica cell walls are all broken down
How many chambers are there in foregut fermenters stomachs?
4
Why are hindgut fermenters usually smaller or more leanly built than foregut fermenters? Give examples of hindgut fermenters
They have a faster system because it is more efficient and tend to be more resistant to tannins
E.g. zebra, rabbits, horses
Smaller species have evolved coprophagy. What does this mean? Give an example
Means they eat faeces
E.g. rabbits,
Capybara- hydrochoerus hydrochaeris
Why have some species evolved Coprophagy?
Faeces has nutrients still left over/ the material has not been fully processed
Why is Coprophagy seen in smaller species/ species with a smaller gut?
The passage time is much smaller
What modification do wombats have and why?
Have a modified gut so have square ooo to scent mark so it doesn’t roll away
What do foregut fermenters allow more utilisation of?
Cellulose
Define home range
Area you need to do about your daily business
What does home range size correlate with?
The size of the animal
