Fractals play an important role in biology. A great deal of work has been done to discover the fractal properties of genetics. Chromosomes are now known to have a tree-like structure with a dimension of 2.34. In addition, using microprobes, it was determined that protein surfaces have a dimension of 2.4. Glazier et al. showed that DNA has fractal properties which helps in understanding evolutionary relationships. Xiao et al. showed that animals, plants, and humans have nucleotide sequences with fractal properties and that the intron and extron sequences are very different in their fractal properties. Work has also been done with protein ion channels, and it has been determined that the timing of their openings and closings have fractal properties.

Fractals patterns have also been found in the body. For example fractal patterns have been seen in the structure of lungs, intestines, and leaf mesophyll, and because these patterns allow for a greater surface area, they aid in the absorption of oxygen, carbon dioxide and nutrients. Fractals are also present in blood vessels, bile ducts, bronchial tubes, and leaf vascular tissue, allowing for distribution and collection of nutrients. Nerves which are responsible for relaying messages also contain Fractal patterns. It was originally thought that young people have a more normal and steady heart beat, and older people have a more random and irregular heart beat. However, there has been new evidence for the opposite theory: that heart rate tends to stabilize with age. Young people’s hearts tend to show more chaos and therefore more relation to fractals, providing for greater adaptability to the environment.

The structures of plants also exhibit fractal patterns. Different species of plants have different fractal dimensions of their leaves. Fractal Dimension is found to increase over time for root systems and to increase with complexity and developmental stage for algae. Fractal properties have also been attributed to pathogen and diaspore dispersal among plants. Plants such as weeds which disperse their seeds among great distances have a more irregular patchy distribution of offspring and thus have a lower fractal dimension. Plants which are more conservative in their seed dispersal tend to create a more uniform offspring distribution and will have a higher fractal dimension.