Living things are made up of animals and plants. Living things engage in many different processes in order to survive. The seven life processes characterize the living things. The life processes are always represented by the acronyms MRS GREN or MRS NERG which simply refer to the same thing. The letters in the acronyms stand for Movement, Reproduction, Sensitivity, Nutrition, Excretion, Respiration and Growth. All living organisms must portray all these characteristics. All the characteristics of living things are explained as follows.
Movement is one of the characteristics of living things. They move in order to get food or to escape danger or just as a means of survival. Movement can also be known as locomotion. Animals move on land, in air or in water. They move their whole bodies from one place to another to look for food or to escape prey. Birds are capable of flying in the air from one point to another. Humans on the other hand can move freely on land in their daily routines or as a way of surviving. Animals of the amphibian family move freely in water and also on land. Frogs and newts can hop on land and at the same time swim in water. Fish have the ability to swim under water by the help of their fins (Kalman, 1998,pg 22).
Plants also can engage in movement. However their whole bodies cannot move from one place to another. They can only move their roots towards water as they grow and towards the centre of the earth. They can also move their stems hence leaves towards light (Kalman, 1998).
This is an important process in living things. This is the process where living things generate new offsprings that resemble them. However they must reach the maturity stage in order to reproduce. Animals produce their young ones known as babies. Amoeba belongs to protists. It has a single cell body which splits to two in its reproduction process. Mammals are known to make eggs and sperm but the fertilized eggs remain inside the mother’s bodies till they are babies and ready to be born. Human beings being mammals undergo this process. Other animals lay eggs which later hatch to young ones (Hunter, 2009,pg 161). These include birds and snakes.
The amphibians also lay eggs which are fertilized in water by the males. Their young ones are known as tadpoles. On the other hand plants also reproduce. Unlike animals, they use their flowers as reproduction organs where seeds are produced. These seeds grow into big plants (Hunter, 2009).
Sensitivity means response to external environment by the living things. Living things notice and understand changes in their external environment and hence respond or react to them with the aim of controlling their internal environment. Mammals can be observed to shiver whenever it is cold for example rabbits. Human beings also portray this trait. This is an evidence to their reaction to temperature changes (Claybourne, 2012). Animals are basically sensitive to what happens around them. They also have complicated nervous systems. They have the sense of sight, hearing, touch, smell and taste. Humans sweat whenever temperatures are high as a way of reaction to environmental change.
Plants also respond differently to stimuli. They portray phototropism which is a survival mechanism. With this, plants are able to use their leaves to trap more sunlight which is essential for their survival. They can also use their roots to sense the presence of water and move towards it (Claybourne, 2012).
Nutrition is the taking in of food by the living things in order to stay alive. By this they are in a good position to supply themselves with energy. Animals do not manufacture their own food. Animals feed on other animals and on plants as their food. Food is important to animals as it helps them to grow and repair their body cells. These cells require nitrogen. This nitrogen is found in foods like meat, peas and beans. Human beings are omnivorous because they can feed on both meat and vegetables. In animal kingdom, there exist herbivores, omnivores and carnivores (Kalman, 1998, pg 18). Lions are carnivores because they feed on flesh only. Amphibians feed on small insects and animals.
Plants make their own food through the process of photosynthesis. They use carbon dioxide gas and water as the main raw materials. Chlorophyll is however necessary and with the help of energy from the sun. Oxygen is the byproduct of this process (Hunter, 2009).
This is the process by which living things remove harmful substances from their systems as waste products. These waste products can be carbon dioxide, water and nitrogen. Animals like dogs and cows excrete carbon dioxide by breathing out. Water vapor is also excreted through breathing out. Animals and human beings need to excrete so as to help them grow and repair cells of the body. Waste is excreted from them into the blood. From the blood, the kidneys take the role of removing the nitrogen. The wastes are removed from the body through sweat, urine, urea and salt (Claybourne, 2012, pg 19). Amphibians excrete through their skin. This can be identified in frogs, newts and salamanders.
Plants excrete nitrogen but in very small amounts. This is because plants do not possess organs to remove it. The nitrogen is stored in cells after being converted to a harmless form. Vacuoles store the waste which later falls out from the leaves.
Respiration simply means breathing. It involves releasing of chemicals. All living things need oxygen to stay alive. This oxygen is used to turn food to energy. Animals and plants respire and in the process exchange gases between themselves and the surrounding. Cells need oxygen in order to undergo respiration for instance in the mitochondria. This oxygen is used in the process to break down nutrients and chemical energy is released. Many animals like cows, dogs, cats and birds use the lungs to obtain oxygen and in the respiration process (Kalman, 1998, pg 14).
Amphibians like toads and frogs use both lungs and gills to respire. Lungs are used when the amphibians are on land while gills are used when they are in water. However the tadpoles only use gills to breathe since they spend all their time under water. Plants also respire. They use tiny holes under the surface of their leaves known as stomata. Plants respire oxygen during the day while carbon dioxide during the night.
Living things have the characteristic of growth. They increase in size by growing wide and taller. Baby animals grow gradually to big animals. They increase in size in a definite shape. Human beings give birth to babies that gradually grow to become full grown adults. Young ones of amphibians are known as tadpoles. The tadpoles use gills to respire and also a fin and a tail to swim in water. However when they grow into adults, they lose the tails and develop legs to help them move on land. They also develop lungs for breathing (Claybourne, 2012).
Plants also grow by producing new cells and tissues. New cells are produced through mitosis. In this process, seedlings grow to bigger plants. Plants grow taller and wider and their shapes keep changing all the time. Growth can be observed in increase in the sizes of leaves, flowers, roots and stems (Claybourne, 2012).
All living things must possess the above characteristics which are of great importance for their survival.