SCIENCE - YEAR 5
|
|
INVESTIGATING
LIVING THINGS |
|
1. MICROORGANISMS 1.1 Microorganisms are living things, they are also known as microbes.
1.
The following are some types of microorganisms.
2. All microorganisms breathe.
3. Like all
microorganisms, bread mould grows.
4.
Some microorganisms move.
5.
Microorganisms are very small. They cannot be seen with naked
eye. We have to
use a microscope to see microoranisms. Magnifying glass can be used to observe
certain microorganism such as yeast.
Magnifying glass
Microscope
1.2
Harmful and useful microorganisms
1.
Many microorganisms are very harmful but some are useful to human.
Useful microorganisms are used in the following processes.
2. Pathogens
Microorganisms that caused diseases are called pathogens. Some of
the diseases caused by pathogens are as shown below:
3. Some ways to
prevent diseases. Keeping ourselves and surrounding clean can prevent many disease caused by microorganism. .
2.1 Ways different animals ensure the survival of their species Some animals looks after their eggs and young. Examples of such animals are: Different plants have different ways to ensure the survival of their species 1. Plants have to disperse their seeds far away to avoid competition. 2. Plants depend on four agents to disperse their seeds. These agents are : (a) Explosive mechanism Example : Rubber fruit Balsam fruit - When the rubber or balsam fruits mature, they split open and the seeds are thrown far away. (b) Wind Example : ![]() - Shorea and lalang seeds are small and light. - They also have fine hair and wing-like structures to help them be blown away. (c) Water Example : - There are air spaces in the coconut and water lily to help the seeds float in water. Example : - The love grass has hooks that can cling on the fur of animals. - The papayas are fleshy and brightly coloured fruits which are eaten by animals. 2.3 The importance of survival of the species If plants become extinct: - there will be a shortage of food - other hervivorous species will become extinct, followed by carnivorous species 3.1 Food chains 1. A food chains - shows how organisms depend on one another for food - shows the relatioship in one direction only - always starts with green plants called producers 2. (b) The grasshopper is the primary consumer. (c) The frog is the secondary consumer. (d) The eagle is the tertiary consumer. ![]() (b) The deer is the primary consumer. (c) The fox is the secondary consumer. (d) The tiger is the tertiary consumer. 3. Herbivores are animals that eat plants and parts of plants. Example : Example :
5. Ombivores are animals which eat
both plants and other animals.
Example : 3.2 Food webs 3. For example, if the number of rats increases, the number of paddy plants will decrease and the number of grasshoppers, birds and eagles will decrease, because there is no or little food. However, the number of owls will increase and so will the number of snakes because there are more rats to eat. 4. Some animals eat onlu one type of food. Example : ![]() 5. These animals will die out and become extinct when their food source is not available. |
|
|
|
copyright
© 2005
|
NOTE
Subscribe to:
Posts (Atom)
0 comments:
Post a Comment