“Yes, well there are spirals in botany too, one of the best known being the overlapping spirals that you can see in the sunflower head. There is an equation for this sort of spiral (Note 1), of which the Fibonacci spiral is a particular case, but some species of snail do, pretty much, hit the exact spiral that comes from the Fibonacci sequence.” 3) Is it relevant to talk about the Fibonacci sequence in botany? Why? However, I say roughly, because actually, not all snail species conform to the Fibonacci sequence. This doesn’t grow according to a geometric sequence, or a linear one, but (roughly) a Fibonacci one (in terms of the increasing area that each successive part of the spiral sweeps through). So for instance the spiral of a snail shell, which starts small, in the centre of the snail, and grows wider towards the edge of the snail. “It is useful and interesting because it describes fairly well how certain things in nature grow. This is the way certain specialized things in nature grow, so it is useful.” 2) In your opinion, what is interesting about this sequence? We get the next number by adding the previous two, so it goes 0, 1, 1, 2, 3, 5, 8, 13, 21, 34 etc. The Fibonacci sequence is a bit more complex. We also have a linear sequence where we add the same number again and again: 2, 4, 6, 8 etc. One type of sequence is the geometric sequence that we use if we wish to describe population growth: 2 rabbits make (say) 4 rabbits, which make 8, which make 16 etc. “The Fibonacci sequence is one of many sequences we use to describe growth.

Q&A on the Fibonacci Sequence 1) What is the Fibonacci sequence? This sunflower head has 55 clockwise spirals and 34 counter-clockwise spirals (34 and 55 are successive numbers in the Fibonacci sequence.

Fibonacci sequence spirals in nature