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  Answer quick check questions from page 123.  Answer Biochallenge questions 1-4 on page 125.  Answer the following chapter review questions from pages  2, 3, 5, 6, 11, 12a, 13 and 14