Adaptations for nutrition

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Adaptations for nutrition BY2
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Types of nutrition
Nutrition is the process by which organisms
obtain energy to maintain life functions and
matter to create and maintain structure. There
are various ways in which this can be
done Autotrophic nutrition Autotrophic organisms
utilise an energy source to make their own
organic molecules from simple inorganic molecules
e.g. green plants, algae and some bacteria carry
out photosynthesis to make organic glucose from
the inorganic molecules .. and
., using energy from the Some
bacteria synthesise organic compounds using
energy derived from .... reactions
e.g. bacteria respiring at deep sea hydrothermal
vents. This is known as chemosynthesis.
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Heterotrophic nutrition Heterotrophic organisms
consume complex organic food material and break
it down into smaller, soluble molecules which
they then absorb and assimilate. Heterotrophs
include animals, fungi, some protoctista and some
bacteria. There are several different types of
heterotrophic nutrition

• Holozoic feeders these organisms have
  specialised digestive systems
• Carnivores
• Herbivore
• Omnivores
• Detritivores -

2. Saprophytes (or saprobionts) feed on ....
or decaying material and do not have specialised
digestive systems. They carry out external
digestion in which they feed by secreting
extracellular .. e.g. amylase or cellulase
onto the food material outside their body. They
then absorb the soluble products of digestion
(e.g. glucose monomers) by diffusion. All fungi
and some bacteria are saprophytes. 3. Parasites
are organisms that live in or on another
organism, the host. The parasite gains
nourishment and causes harm to the host. 4.
Mutualism is a close association (symbiosis)
between members of two different species, in
which both organisms benefit from the
relationship. e.g.
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Identify the types of nutrition carried out
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Human digestive system
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Human digestive system(alimentary canal)

• Functions of the digestive system
• Ingestion
• Mechanical digestion
• Chemical digestion

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Structure of the mammalian gut wall
Ileum T.S.
Photomicrograph Plan diagram
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Describe how the longitudinal and circular
muscles work together to move a bolus of food in
one direction along the gut______________________
__________________________________________________
__________________________________________________
__________________________________________________
_________________________________________Which
component of our diet helps stimulate
peristalsis? explain why_________________________
__________________________________________________
__________________________________________________
_________________
Peristalsis
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Glands in the gut

• Glands produce large amounts of secretions, some
  of which contain digestive enzymes. There are
  three types of glands in the gut
• 1. Large glands found outside the gut with
  secretions passing through tubes or ducts into
  the gut cavity.
• Salivary glands produce saliva which contains
  mucus to lubricate the food and amylase which
  breaks down its substrate ___________ into
  maltose.
• Liver -
• Pancreas -

• 2. Glands in the form of cells in the MUCOSA
  secretions pass directly into the gut cavity
• Gastric glands in the stomach mucosa secrete
  gastric juice, this contains
• - Hydrochloric acid -
• - Endopeptidase -
• Glands found at the base of the villi in the
  small intestine mucosa. These secrete digestive
  enzymes exopeptidase, lipase and maltase.
• 3. Glands in the form of cells in the SUBMUCOSA
  secretions pass directly into the gut cavity
• Brunners glands in the submucosa of the duodenum
  secrete alkaline mucus
• What is the function of this alkaline mucus ?

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Organisms with a varied diet require more than
one type of enzyme to completely digest
carbohydrate, protein and lipid substrates
present in the ingested food. Digestive enzymes
Enzyme Substrate Product Gland/s it is secreted from Site of action
Salivary amylase
Endopeptidases
Pancreatic amylase
Exopeptidases
Maltase
Lipase

• 1. Explain the difference between an
  endopeptidase and an exopeptidase.
• Which enzymes are involved in the complete
  digestion of
• Carbohydrates?
• Proteins?
• c) Lipids?
• 3. Note BILE is NOT an enzyme. It is produced
  by the liver and stored in the gall bladder
• Functions of Bile

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Ileum

• The ileum is well adapted for absorption as it
  has the following features
• Specialised cells in the mucosa of the ileum

• 1. Columnar epithelial cells give 2 adaptations
  of these cells
• 2. Goblet cells what do these cells secrete?
• why?
• Label a goblet cell and an epithelial cell
• on the micrograph

T.S. Ileum showing cells of the villi
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A villus
Substance Method of absorption
Glucose
Amino acids
Fatty acids and glycerol
Which blood vessel transports absorbed nutrients
to the liver?
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• Large intestine
• The large intestine is about 1.5 metres long and
  is divided into the caecum, the appendix, the
  colon and the rectum. By the time it reaches
  the rectum, indigestible food, sloughed off
  cells, bacteria and undigested cellulose (dietary
  fibre) are egested as faeces.
• What is absorbed in the large intestine?
• Uses of the products of digestion

Glucose
Amino acids
Uses of products of digestion
Lipids
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Summary sheet annotate this to help consolidate
what you have learnt about the digestive system.
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Adaptation for different diets

• Reptiles and amphibians swallow food immediately
• when caught, but in mammals food is retained in
  the
• mouth whilst it is cut up and chewed.
• Mammals have a palate that separates the nasal
  cavity from
• the mouth. This allows the food to be retained in
  the mouth
• rather than swallowed whole between breaths.
  Different
• mammals have different gut and dental
  adaptations specialised to their diet.
• Dentition
• Teeth are important in the .. digestion
  of food. Chewing is important as it makes it
  easier to swallow and also increases the ..
  .for enzyme action. Human teeth are
  relatively unspecialised as humans
  are.. However there are four
  different types of teeth with different
  functions.

Tooth Type Function
Incisors
Canines
Molars and pre molars
Question. How many teeth do humans have
altogether?
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Herbivore adaptations .
This diet is cellulose based. Cellulose is
difficult to digest. Herbivore teeth are
adapted for GRINDING to increase surface area
for bacterial cellulase action. Herbivore
dentition

• Features of grazing herbivore dentition
• Incisors and horny pad
• Canines
• Molars
• Diastema
• Jaw movement
• Open roots

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Carnivore adaptations
Carnivore dentition

• Carnivorous mammals have teeth adapted for
  catching and killing prey, cutting or crushing
  bones and for tearing meat.
• Features of carnivorous dentition
• Small sharp incisors
• Large curved canines
• Premolar/molars
• Carnassials
• Powerful jaw muscles
• Jaw movement
•  

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Adaptations of the gut Ruminant Herbivores

• Ruminants are animals such as cows and sheep
  which mainly eat grass and forage.
• This food contains a lot of cell walls made out
  of .. which they are unable to digest as
  they do not produce the enzyme
• To overcome this, they have a specialised stomach
  composed of 4 chambers. One of these chambers,
  the RUMEN, is where MUTUALISTIC . live.
• Cellulose digestion
• The grass is chewed, mixed with saliva and
  swallowed. In the rumen it is churned and mixed
  with bacteria that secrete cellulase to digest
  ., forming ß-glucose. The glucose is
  fermented (under anaerobic conditions) to form
  organic acids which are absorbed into the blood,
  providing energy for the cow. The waste products
  are carbon dioxide and methane which are passed
  out. The saliva contains urea which the bacteria
  can use as a nitrogen source to manufacture amino
  acids and proteins. 
• The contents of the rumen are regurgitated to
  the mouth via the reticulum, where the grass is
  rechewed this is known as chewing the
• When the rumen contents are reasonably liquid
  they pass to the omasum where is reabsorbed
  and the abomasum (the true stomach) for digestion
  of protein. 
• The bacteria in the rumen are kept separate from
  the acid found in the abomasum. Once the bacteria
  enter the abomasum they are killed by the acid.
  And provide an important source of ..for the
  animal.

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Non-ruminant herbivores
e.g. rabbit In the rabbit the
caecum is enlarged to accommodate the cellulose
digesting bacteria. As the bacteria are towards
the end of the gut, regurgitation is not
possible. Instead, refection (or copraphagy)
occurs, where the rabbit ingests faecal pellets
so that the material passes through the gut twice
to increase efficiency of digestion.   Question
Why are the guts of herbivores longer than those
of carnivores and omnivores?  
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Parasite nutrition.
Definition of a parasite.

• The pork tapeworm a parasite of the gut.
• Taenia solium, the pork tapeworm has two hosts
• the primary host is the human where it lives in
  its adult form in the intestines.
• the secondary host is the .. where it lives
  in the muscle as cysts.

The adult tapeworm.
Add the labels hooks, suckers and proglottid
(segment)
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Tapeworm lifecycle (note you do not need to
memorise the details of this.)
Fill in the labels. Using the diagram to help
you, what simple precautions should be taken to
avoid becoming infected with tapeworm?
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PROBLEMS FACED BY THE TAPEWORM ADAPTATIONS THAT THE TAPEWORM HAS EVOLVED
Gut is in constant motion (peristalsis and stomach churning)
Extremes of pH along the gut, exposure to digestive enzymes and the hosts immune response
Reproduction - Unlikely to find a mate in host High offspring mortality Difficult for eggs to reach a new host
Host death

• Question
• Why does the tapeworm not require a digestive
  system?
• How is the tapeworm adapted to gain its
  nutrients?
• (hint- think about the size and shape of the
  organism)