THE CHARACTERISTICS OF LIVING THINGS

Living things have characteristics different from those non-living things. Below are explained in simple details...

Movement/locomotion 

All living organisms are capable of movement. Movement is the change of position of the whole organism or just part of an organism. For animals and unicellular organisms the movement is of the whole body. This is known as locomotion. 

Most animals move about using legs, wings or fins. Unicellular organisms such as amoeba, paramecium and euglena use the locomotory structures pseudopodia, cilia and flagella respectively. 

In plants only part of it may move towards different factors such as light, water, gravity etc. They move by growing. Their roots grow down in the soil and their shoots grow up into the air or towards a source of light. 

Irritability (sensitivity)

Irritability is the ability of an organism to respond to a stimulus. Stimulus (plural; stimuli) is anything that causes a response in an organism. 
Examples of stimuli include: an alarm clock, a smell of breakfast cooking and a fly landing on your skin. 

All living things are sensitive to certain changes in their surroundings, that is, they are aware of what is happening around them. This is possible because they have special organs known as sense organs by which they detect these changes. 

Examples of sense organs include: eyes for vision (sight); skin for temperature, touch, pressure detection; tongue for tasting; nose for smelling; and ears for hearing and body balance. Plants do not have sense organs but are still able to detect and respond to things like gravity, water and light.

Feeding (Nutrition) 

All living things need food to provide energy for such activities such as growth, repair and health. Animals get their food by eating other living things or food materials that were once living things. Herbivores (e.g. rabbits) eat plants, carnivores (e.g. lions) eat other animals, and omnivores (e.g. humans) eat animals and plants. 

Plants make their own food through the process called photosynthesis. The process of taking in food, synthesizing it, digesting and oxidizing it to release energy or build the body is called nutrition. 

Respiration 

Respiration is the breaking down of food materials within cells to release energy. Respiration usually involves the use of oxygen. All living things need energy for movement, growth and development, and functioning of body organs.

Excretion

All living things produce wastes such as carbon dioxide, water, urea, ammonia etc.. Some of these chemicals if left to accumulate in the cells would seriously poison the living organism hence they need to be removed. 

The process of removing metabolic waste products from the body of living organisms is called excretion. Waste products are removed from the body by excretory organs such skin, kidneys, lungs and liver.

Reproduction 

Reproduction is the process by which living things produce new individuals of their own kind. All living things reproduce, to replace organisms lost by death. If a group of organisms does not reproduce fast enough to replace those which die, the group becomes extinct. 

Reproduction ensures continuation of life when parent generation dies. Human beings bear babies; birds hatch chicks; and plants produce seedlings as new organisms, which eventually grow to mature organisms to replace those lost by deaths.

Growth 

Growth is defined as an irreversible (permanent) increase in size and dry weight of an organism involving differentiation. All living things need food in order to grow and build up their bodies. 

Animals grow until they reach certain adult size, but most plants can grow continuously throughout their lives. 
Examples of growth in living things

Examples of living things 

Fucus (bladderwrack) 
Man
Cow
Flagellate bacilli
Mushroom
Oak
Butterfly etc.

                A table of differences between living things and non-living things

Living Things	Non Living Things
They respire	They don't respire
They grow	They don't grow
They respond to stimuli	They don't respond to stimuli
They reproduce	They don't reproduce
They excrete	They don't excrete
They feed	They don't feed
They move	They don't move

                    A table showing differences between plants and animals 

PLANTS	ANIMALS
(i)They are autotrophic, i.e. they can make their own food	They are heterotrophic i.e. they feed on complex organic compounds
(ii)Contain chlorophyll, can undergo photosynthesis.	No chlorophyll, cannot undergo photosynthesis
(iii)Growth occurs in some parts only i.e. root and shoot tips.	Growth occurs in all parts of the body.
(iv)They have branched bodies	They have compact bodies
(v)No nerves, muscles, blood system or special sensory cells.	Have nerves, muscles, blood system and special sensory cells.
(vi)Usually rooted in the ground and do not move from place to place.	Not rooted in the ground, move to get food and escape enemies.
(vii)Have no digestive system	Have digestive system needed to break down food
(viii)Cells of plants have cell walls	Cells of animals have no cell walls