Fibonacci in Nature
Karam Habchi
Providence College Class 2012 Alumnus
Mathematics & Biology Double-Major
The Fibonacci sequence is the numbers in the following integer sequence: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, etc. The first two numbers in the sequence are 1 and 1 (alternatively, 0 and 1) and each subsequent number is the sum of the previous two numbers. In mathematical terms, the sequence is defined by Fn = Fn-1 + Fn-2 where F0 = 0 and F1 = 1. The sequence is named after Leonardo of Pisa who was also known as Fibonacci. He first introduced the sequence in his book on arithmetic, Liber Abaci, which was written in 1202 (although it wasn’t named the Fibonacci sequence until the 19th century). In the book, Fibonacci used the sequence to describe the growth of an idealized rabbit population and centuries later it was discovered that the Fibonacci sequence could describe many patterns that occur biologically in nature. We will explore some of these naturally occurring patterns, which include bee ancestry, nautilus shells, phyllotaxis (the arrangement of plant leaves), and plant seeding. We will also discuss the relationship between the Fibonacci sequence and the golden ratio, a number that has fascinated intellectuals since 500 BC, and how the golden ratio influences plant biology and its possible connection to human biology as well.
