Diversity in Animals

1. Diversity in Animals

2. Dog Jaw Structure http://www.wirefoxterrierassociation.co.uk/dentition.htm

3. Why do they need teeth? In carnivores, the front of the skull has a pair of enlarged canine teeth, and the lower jaw moves only in an up and down direction, which assists with the capture, killing, and holding of the prey. The premolars and molars located toward the rear of the mouth grind and crush the food into pieces that can be swallowed and then digested.

4. Dogs muscles • Dogs have 3 main jaw muscles: • Masseter - provides slow, powerful jaw closure with forward/back/side-to-side chewing motions. • Temporalis - delivers fast and forceful jaw closure in the up/down plane. • Pterygoid - produces sideways jaw movements • In carnivores the temporalis muscle drives the canine teeth forcefully into its prey.

5. Teeth • Dogs go through many different stages of teeth that have different uses. Fangs for grabbing, incisors for nibbling, pre molars for tearing and molars for crushing bones • Canine teeth help the wild dogs catch their prey; holding objects in the mouth for the normal house hold dog.

6. Cows Jaw structure http://www.wonderquest.com/2006-09-05-cow-jaw.jpg

7. Teeth-How they eat? • Cows have 32 teeth. They have 6 incisors and 2 canines in the front on the bottom. There are no incisors on the top; instead cattle have a dental pad (horny pad). Cows have 6 premolars and 6 molars on both top and bottom jaws for a total of 24 molars. There is also a large gap between the incisors and molars. This configuration allows cattle to harvest and chew a large amount of grass. • Because their teeth are manly used for grinding, cows use their tongues to grasp or gather grass and then pinch it off between their incisors and dental pad. Since they do not upper incisors, cattle cannot bite off grass very well, and they are inefficient at grazing closely. The inside of the cheeks and palate are rough which helps hold feed in while cows chew with a side to side motion.

8. Cows Jaw Muscles • Cows also have 3 main jaw muscles: • Masseter - provides slow, powerful jaw closure with forward/back/side-to-side chewing motions. • Temporalis - delivers fast and forceful jaw closure in the up/down plane. • Pterygoid - produces sideways jaw movements • Herbivores have well-developed masseter and pterygoid muscles because they need to move their jaws in a circular motion to grind and crush plant material.

9. Human Jaw Structure • http://www.daviddarling.info/images/human_teeth.jpg

10. Human Teeth • Humans are omnivores so thy eat both meat and plants, therefore need both • incisors - are the sharp-edged teeth in the front of the mouth that bite and cut food. We have 8 of these. • canines - are the pointed teeth next to the incisors that grip and tear food. We have 4 of these. • premolars - are the teeth just behind the canines. They help the canines with chopping and assist the molars with grinding. There are 8 of these in our mouths. • molars - are the teeth in the back of the mouth that pound, grind and crush food into mush so that it can be swallowed. We have 12 molars.

11. Human Jaw Muscles Masseter - provides slow, powerful jaw closure with forward/back/side-to-side chewing motions. Temporalis - delivers fast and forceful jaw closure in the up/down plane. Pterygoid - produces sideways jaw movements They can move there jaw side to side, forwards and backwards and up and down.