Internal and external growth
Firms are rather like shellfish; they are constrained by their shells. To go on growing they have to shed the old one and grow a larger, new one. So, many things have to adapt and change as size grows beyond a certain critical size. For shellfish it is the shell, for a firm it is the way that it is organised. This is why many companies seem to grow in a cyclic manner.
Growth is often split into two types - internal and external. These can be defined as follows:
Internal growth is where a firm gets larger from expanding by using its own resources. This is often known as organic (natural) growth. Growth comes from increased sales and higher profits, which are then reinvested in the business.
External growth is when a firm grows by taking over or merging with another firm (integration). This is often known as inorganic growth.