Types of Digestive System - CRCBiologyY11 by hcj

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									Long weekend homework powerpoint
LEARNING OUTCOMES
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
     matter.
    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
  stomach.
 Ruminants (cattle, sheep, goats) have a vastly enlarged,
  compartmentalised stomach for bacterial fermentation.
 Draw a flowchart to show how digestion works in a ruminant
  animal.
   The hindgut is comprised of
    the small intestine and large
    intestine.
   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
    on.
   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
    125.
   Answer the following chapter review
    questions from pages 125-127
     2, 3, 5, 6, 11, 12a, 13 and 14

								
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