Life Processes
Biology is the study of living things. All living things are called organisms, both plants and animals are living organisms. But how we decide whether something is living or non-living depends on 7 life processes. If something is living it will carry out the 7 life processes below.
Both animals and plants have the ability to move.
Plants are rooted and move slowly as they grow. Their roots move down
into the soil and their stems move up towards the light. Animals on the
other hand move quickly and can move their entire bodies. They can
move in search of food, shelter or to avoid danger.
2. Respiration
Respiration is the process of extracting energy out
of the food we eat. All living things respire because they need energy
to grow, to replace worn out parts and to move. Respiration takes place
in the mitochondria of the cell. There are two types of respiration,
with and without oxygen. Aerobic respiration uses oxygen and releases a
large amount of energy. Anaerobic respiration does not require oxygen
and releases a smaller amount of oxygen.
3. Sensitivity
All living organisms are sensitive, this means that
they have an awareness of changes in their environment. Animals respond
quickly to stimuli such as heat, light, sound, touch and chemicals
which have taste and smell. On the other hand plants generally appear
less sensitive and their response is slower. Plants respond to light
by moving their leaves towards it, the flowers of some plants open in
the morning and close at night when it is dark. Some plants, however, do
respond quickly such as the Venus flytrap response to touch.
4. Growth
All living organisms grow. Plants continue growing
throughout their lives. Animals stop growing once they reach
adulthood. Even when growth stops, materials within an animal’s body are
still being replaced from its food.
5. Excretion
All living things make waste products these can be
useless or harmful to it and therefore need to be got rid of. Excretion
is the process of getting rid of metabolic waste. Plants store waste
substances in their leaves, the waste is removed when their leaves fall
off. Animals breathe out waste carbon dioxide, other waste substances
leave the body in urine and sweat. Note: Getting rid of faeces or
undigested food is not excretion but egestion.
6. Reproduction
All living things must produce offspring like
themselves in order for their species to survive. This is the process
known as reproduction. Plants produce seeds that give rise to new
plants of the same species. Animals lay eggs or have babies.
Reproduction can be of two types, Sexual which involves two parents and
the union of two gametes and Asexual where one parent can reproduce
itself.
7. Nutrition
Nutrition is needed for energy and growth, both
plants and animals need food. Plants are able to make their own food by
photosynthesis. They use sunlight to turn simple molecules like carbon
dioxide and water into more complex carbohydrate molecules. Animals
are unable to make their own food so rely on other plants and other
animals for their nutrition. Animals take in complex substances and
break them down into small, simple, soluble molecules which can be used
for energy and growth.
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