Biology Tutorials > Control of Growth & Development > Growth Patterns

Growth Patterns

Cicada shedding its old shell for a new growth

Table of Contents

When measuring growth, it is more desirable to use dry mass as a reliable indication. However, since you can’t just ‘suck’ an organism dry, we tend to measure growth as an increase in height or ‘fresh’ weight.

The following indicates various growth curves for the corresponding organisms.

Sigmoid Growth Curve

The sigmoid curve is a ‘growth average’ representing all organisms, where young organisms experience rapid accelerating growth to cope with their environment, followed by a continuous steady growth. Towards maturity, an organism’s growth rate slows down until no growth occurs.

Annual Plant Growth

Annual plants only live for one year. At first, the embryo of the seed harnesses the seed food supply and is illustrated by a decrease in growth to begin with as the food supplies shrink. Once this energy kicks in, and photosynthesis can occur in the plant, growth begins to accelerate. Throughout the year the plant will continue to grow, and when it has reached the Winter months, and seeds have been dispersed, it withers and dies, illustrated by the decrease in mass.

Tree Growth

Perennials such as trees continue to grow year after year, and in the instance of trees, can grow for an immense space of time. Most growth occurs in Spring.

Human Growth

Humans have two phases of growth ‘spurts’, one in infancy and one in adolescence. In between infancy and adolescence, there is a period of steady growth while adulthood is when growth halts.

Insect Growth

Insects possess exoskeletons (an exterior skeleton) which means continuous growth cannot occur without this skeleton allowing so. In light of this, the insects must shed their outer layer for growth to continue. This molting of the skin allows body mass to increase.

Credit: Stephanie Castle

Quiz

Write the letter of your answer in the space provided. Select from the box below.

A. Sigmoid Growth Curve
B. Annual Plant Growth
C. Tree Growth
D. Human Growth
E. Insect Growth

1. Insects shed exoskeleton to allow body mass to increase.

2. A ‘growth average’, where young organisms experience rapid accelerating growth to cope with their environment followed by a continuous steady growth.

3. Two growth spurts, one in infancy and another in adolescence.

4. For some plants, the lifespan is only about a year and in this lifespan, they continuously grow until they wither during Winter months.

5. Some trees form annual rings as they continue to grow year after year.