A carnivore is an animal that requires a staple diet consisting mainly of animal tissue through
predation or scavenging usually dieting meat. While an herbivore is an animal that eats plants or
plant like organisms and an omnivore is an animal that consists of both diets of meat and plants.
Shark are a carnivore and consists a diet of fish, crustaceans, mollusks, plankton, krill, marine
mammals and other sharks which. Sharks has canine teeth which allows it to rip and the tear of the
flesh of its prey. The jaw chews up and down, but most sharks swallow their food whole or consume
it in large pieces. The shark’s food goes down the wide and short oesophagus. Sharks have U shaped
stomachs which contains strong acids and enzymes to dissolve most of what has been consumed.
The stomach produces a liquid mush, which then enters the intestines because of the pyloric valve
which is quite small. The stomach leads to the intestine which is referred to as spiral valve. The
intestines are short but have a large surface area due to the fact of the infolding of the inner surface.
The digestive tract leads to the rectum and to the cloaca, which is an opening for the urinary
digestive.
Giraffes are herbivores that consist of a diet of leaves and shrubs, while when fully grown can eat up
to 70kg of food in a day. Giraffes contain one set of molars at the front of their mouth on the bottom
jaw and another set at the back of their top jaw, they use their teeth to cut up food before the back
teeth and are able to chew the last bits before swallowing. The giraffe firstly chews its food and it
travels down through the oesophagus and in top the first part of the stomach called the rumen, it
then passes quickly to the reticulum, after this occurs the food is regurgitated back into the mouth
which is then chewed again and then passed through to the omasum and then the abomasum.
Mechanical digestion is the thick layer of the saliva located on the giraffe’s tongues allowing it to eat
plants and leaves with thorns without pain. The Chemical digestion is that the giraffe has four
stomachs that help with the process of digestion as plants and leaves are hard to digest. This makes
them a ruminant species, as they are able to digest food that other animals can’t, they contain a
special bacterium that helps break down the plants in order for them to produce nutrients.
Rats are omnivores which diets consist of fruit, vegetables, seeds, nuts, bugs, other small animals
and any other edibles they can find. Rats contain four long sharp incisors, twelve molars and only
contain one set of teeth during their lifetime. The rat chews food into particles allowing it to enter
the oesophagus, while saliva is used to minimise the size of the food consumed. The oesophagus
allows the food particles to pass through to the stomach, when the swallowing process begins the
food becomes involuntary. The pancreas then produces enzymes to breakdown glucose,
carbohydrates fats and proteins from the food, it then secretes to the duodenum the first part of the
small intestine. The sac like structures of the rat are kept for ingested food breaking down into small
particles, enzymes help to break down the food and then is released to the small intestine. The small
intestine is divided into three parts the duodenum, jejunum and ileum. The segments breakdown
food from enzymes the pancreas released. Once the nutrients are absorbed it travels through to the
large intestine. The large intestine connects the small intestine to the rectum and functions its
wastages. The cecum is the pouch that the rats have to store their excess food particles before
entering the rectum.
Carnivores, herbivore and omnivores digestion systems all differ. Carnivores digestive
system are quite simple as they have only one stomach, their teeth are sharp and strong
making it easy for digestion. Due to the lack of salivary enzymes, food doesn’t spend long
inside the mouth and is shortly swallowed down through the oesophagus. The stomach for a
carnivore has multiple roles in digestion- a reservoir for food, a sterilising chamber, due to
low pH, a churning chamber to mix food and an intentional site of protein digestion. The
food moves to the small intestine, then joins to the large intestine which consists of the
caecum, colon and rectum, the cecum has no function in carnivores. While Herbivores are
more complex as they consume plants, causing more difficult digestion. To overcome the
difficult digestion herbivores developed a symbiotic relationship with a population of
microflora e.g. the caecum of rumen of ruminants. There are two different types of
herbivores that ferment, those who ferment in the hind gut and the foregut. The difference
is the site of fermentation and the organ used for fermentation. The foregut fermenter
herbivores are a lot more efficient as food is digested first pass through the digestive
system. Omnivores digestive system is very similar to carnivores, but they also contain an
active working caecum. Due to this flexibility omnivores are available to consume a wide
diet, this also prevents losing the ability to synthesise products found in the body. Their
process of digestion is very similar to carnivores allowing them to digest plant matter but
