5. Growth & Development

What you need to know...
  • What conditions are needed for healthy growth and development?
Growth and development
We have looked at how our genes affect the features of living things, however the features of living things are down to more than just their genes. In fact it is possible for two living things with identical genes to actually look quite different. You may know identical twins who have quite different personalities, talents and whom you can easily tell apart. There is another important thing which affects how living things grow and develop which is their environment
In this topic we will consider what conditions will affect growth and development and so what conditions are needed for healthy growth and development.
Growth and development in plants
Lets take a look at an experiment into the conditions needed for growth in cress seeds. This experiment was set up and left for a week.
What does this tell us about the conditions needed for growth?
The cress plants with all of these factors present shows healthy growth and development but the ones without water, oxygen and a suitable temperature have not grown at all. Interestingly, the seed grown without light has germinated but has grown thin and pale. We can conclude that water, oxygen a suitable temperature and light are all important for the healthy growth and development in plants.
Below is a picture of a sugar cane field. Some of the sugar cane plants are growing and developing well but others are stunted in growth and their leaves are yellow or brown instead of green. The soil in this field is becoming deficient in iron, an important mineral in plants. We can conclude that minerals are also important for healthy plant growth and development.

Growth and development in humans

We don't need to tell you that a balanced diet, water, minerals and vitamins are required for healthy growth and development in humans but you may not know about why these vitamins or food groups are important.
If you want to read more about a healthy and balanced diet try the NHS Choices Live Well website. In summary your diet should have a balance between the three main food groups - carbohydrate, protein and fat.
  • Carbohydrates are food such as bread, pasta, rice and potatoes. These are important because they give you energy. Carbohydrates breakdown to form glucose which you should remember is used in respiration.
  • Protein is found in foods such as meat, fish, pulses, eggs and tofu. Protein is used to make up the basic framework of the body's tissues and organs. Protein can be used for energy but only in cases of starvation.
  • Fat is useful in the body for insulation. It is stored under the skin and keeps us warm. Fat is also important because it helps absorb and carry certain vitamins in the blood. Fat, however, is very high in energy and should only be eaten in moderation. It is important to know the difference between saturated fat and unsaturated fat.
    • Eating a diet high in saturated fat can lead to high cholesterol levels in the blood which can lead to various cardiovascular diseases. Saturated fat is found in butter, cheese, animal fat.
    • Eating more unsaturated fats can actually lower cholesterol levels in the blood. Unsaturated fats can be found in food like olive oil, oily fish and nuts.
  • Vitamins and minerals:  You should also get plenty of vitamins and minerals by eating at least five portions of fruit and vegetables per day. The table below shows some vitamins and minerals and their function in the body.    

    Vitamin or mineral

     Foods found in

    Function in human body 

     Vitamin AMilk, eggs, liver, carrots.Prevent eye problems.
     Vitamin B12Fish, red meat, poultry, milk, cheese and eggs.Helps make red blood cells.
     Vitamin CCitrus fruits, peppers, tomatoes, broccoli and spinach.Healthy bones teeth and gums.
     Vitamin DYour skin makes it when you are in the sun! It is also found in egg yolks, oily fishTo absorb calcium (see below)
     CalciumMilk and other dairy products.Strong healthy bones
     IronRed meat, fish, lentils, beans, green leafy vegetables. Some cereals are also fortified with iron.Helps red blood cells carry oxygen around the body.

 A healthy balanced diet