Types of Digestive System

Long weekend homework powerpoint
By the end of this lesson, you should
be able to:
Understand and explain the systems for
processing nutrients in a range of different
heterotrophic organisms.
Herbivores are animals that only eat plant
 Cellulose is the major carbohydrate found in
plants, but it indigestible by animals.
 Cellulose can only be broken down (fermented)
by bacteria, and so all animals that eat plant
matter have bacteria living in their gut.
 Depending on where the bacteria live in the gut,
herbivores are classified into two groups:
1) Foregut fermenters or
2) Hindgut fermenters
The foregut is comprised of the oesophagus and the
Ruminants (cattle, sheep, goats) have a vastly enlarged,
compartmentalised stomach for bacterial fermentation.
Draw a flowchart to show how digestion works in a ruminant
The hindgut is comprised of
the small intestine and large
Hindgut fermenters either
have a modified small
intestine (caecum fermenters)
or a modified large intestine
(colon fermenters).
Figure 5.30 page 121 – Cow and koala; two
different types of herbivores.
Some heterotrophs have highly specialised
diets, eating the pollen or nectar from only one
or two different species of plant.
Nectar is a sugary substance secreted by flowers
to attract animals to feed and help disperse
pollen to other plants when the animals move
As nectar is made of sugar, very little digestion
needs to occur before the glucose can be
absorbed into the blood stream. As such, the
digestive tracts of nectar and pollen eaters are
simple and short. This is also necessary as these
animals are normally tiny in size.
Carnivorous animals are those that eat the flesh
of other animals to obtain their energy and
nutrients for living.
Carnivorous mammals do not generally eat any
plant matter, and therefore, do not require
complicated, modified digestive systems that
are found in herbivores.
Similarly, the protein found in animal flesh is
much easier to digest than cellulose, resulting in
a fairly short and simple digestive system, often
also characterised by a muscular stomach.
Figure 5.30 page 121 – Tasmanian devil (carnivore) and honey possum (nectar feeder)
TEXT 118-123
Answer quick check questions 13-16 from
page 123.
Answer Biochallenge questions 1-4 on page
Answer the following chapter review
questions from pages 125-127
 2, 3, 5, 6, 11, 12a, 13 and 14

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