Fibonacci Sequences and Its Significance

General Studies Paper 3

Context

• Fibonacci spirals are so common in plants today that they are believed to represent an ancient and highly conserved feature, dating back to the earliest stages of plant evolution and persisting in their present forms. But a new study, based on 407-million-year-old fossils, challenges this.

About

• What ties all of these botanical features together is their shared characteristic of being arranged in spirals that adhere to a numerical sequence called theFibonacci sequence.
• These spirals, referred to as Fibonacci spirals for simplicity, are extremely widespread in plants and have fascinated scientists from Leonardo da Vinci to Charles Darwin.
• Such is the prevalence of Fibonacci spirals in plants today that they are believed to represent an ancient and highly conserved feature, dating back to the earliest stages of plant evolution and persisting in their present forms.
• However, our new study challenges this viewpoint. Recently scientists examined the spirals in the leaves and reproductive structures of a fossilised plant dating back 407 million years and surprisingly discovered that all of the spirals observed in this particular species did not follow this same rule.
• Today, only a very few plants don’t follow a Fibonacci pattern.

Fibonacci spirals

• Spirals occur frequently in nature and can be seen in plant leaves, animal shells and even in the double helix of our DNA.
• In most cases, these spirals relate to the Fibonacci sequence – a set of numbers where each is the sum of the two numbers that precede it (1, 1, 2, 3, 5, 8, 13, 21 and so on).
• These patterns are particularly widespread in plants and can even be recognised with the naked eye.
• At first, you may only spot spirals in one direction. But look closely and you can see both clockwise and anticlockwise spirals.
• In a study that analysed 6,000 pinecones, Fibonacci spirals were found in 97% of the examined cones.
• Fibonacci spirals are not just found in pine cones. They are common in other plant organs such as leaves and flowers.
• Due to their frequency in living plant species, it has long been thought that Fibonacci spirals were ancient and highly conserved in all plants.
• However in a study it was found that non-Fibonacci spirals were the most common arrangement.
• The discovery of non-Fibonacci spirals in such an early fossil is surprising as they are very rare in living plant species today.

Distinct evolutionary history

• These findings change our understanding of Fibonacci spirals in land plants.
• They suggest that non-Fibonacci spirals were ancient in clubmosses, overturning the view that all leafy plants started out growing leaves that followed the Fibonacci pattern.
• Furthermore, it suggests that leaf evolution and Fibonacci spirals in clubmosses had an evolutionary history distinct from other groups of living plants today, such as ferns, conifers and flowering plants.
• It suggests that Fibonacci spirals emerged separately multiple times throughout plant evolution.

Conclusion

• Knowing of this study would help in the common understanding of plant evolution and its characteristics.