ADAPTATIONS TO DIFFERENT DIETS

Question 1

how are carnivores adapted? (3)

Answer 1

• mostly protein diet, easily digested
• so short intestine compared to body length
• large intestine straight with a smooth lining

Question 2

how are herbivores adapted? (3)

Answer 2

• plant-diet, difficult to digest
• so long intestine compared to body
• pouched long intestine

Question 3

how are omnivores adapted? (2)

Answer 3

• medium length gut

- pouched long intestine

Question 4

why do omnivores/herbivores have a pouched gut?

Answer 4

• so it can stretch to accommodate the larger amount of faeces produced by digesting plants, containing cellulose

Question 5

what types of teeth do humans have? (4)

Answer 5

• incisors
• canines
• premolars
• molars

Question 6

herbivore dentition adaptations (7)

Answer 6

• incisors on the lower jaw only, with indistinguishable canines
• when eating tongue wraps around grass and pulls it tight across leathery dental pad on the upper jaw and teeth slice through it
• diastema gap separates front and side (premolars) teeth, grass is moved between the grinding surfaces of the molars
• molars interlock like M & W, lower jaw moves from side to side in a circular grinding action
• when grinding surfaces are worn down they expose sharp enamel ridges which makes grinding more efficient
• teeth have open, unrestricted roots so grow throughout the animals lifetime
• skull is relatively moved, lacking in strong muscles because food doesn’t try to escape

Question 7

carnivore dentition adaptions (7)

Answer 7

• sharp incisors to grip and tear muscle from bone
• canine teeth are large and curved for piercing and seizing prey, tearing muscle and killing
• premolars/molars have sharp cusps for cutting and crushing
• specialised cheek teeth, carnassials, sliding past each other like scissor blades, shearing muscle off bone, large & identifiable
• lower jaws move vertically to keep a better grip on prey
• carnivores open jaws more widely
• protrusions on the skull for muscle to insert into bond, leading to a strong grip and bone crushing

Question 8

how do ruminants digest cellulose?

Answer 8

• mutualistic microbes living in the gut that secrete enzymes

Question 9

ruminant

Answer 9

• a cud-chewing herbivore with a stomach divided into 4 (the rumen being the largest) with mutualistic microbes that secrete enzymes living in the gut

Question 10

steps of cellulose digestion (9)

Answer 10

• grass cut by teeth and mixed with saliva to form cud, swallowed via oesophagus to the rumen
• in the rumen food mixes with microbes and they secrete enzymes to digest cellulose into glucose
• products are fermented into organic acids, absorbed into blood and used as energy, waste released
• C6H12O6 = 2CH3COOH + CO2 + CH4
• fermented grass passes to reticulum and reformed into cud, regurgitated into the mouth for more chewing
• cud swallowed and regurgitated many times
• cud passes into the omasum
• then into the abomasum
• then small intestine/large intestine

Question 11

ruminant stomachs (4)

Answer 11

• rumen, where cellulose is digested
• reticulum, where grass is reformed into cud
• omasum, where water and organic acids are absorbed
• abomasum, protein is digested