In a study published in 2008, researchers in France observed a rapid evolutionary change in a plant's seed size in order for it to adapt to urban life.
They found that the seeds on Crepis sancta, otherwise known as hawksbeard, were larger on specimens that lived in urban areas, when compared with the seeds from the plants growing in rural settings.
As the plant's seeds were dispersed by the wind, the researchers suggested that heavier seeds fared better because they would drop on to nearby soil, whereas the lighter seeds would be carried by the wind, resulting in them being deposited on concrete and tarmac, where it was impossible to germinate.
The speed in which this trait was expressed in the urban-dwelling plants surprised the researchers.
Professor Alberti said the changes that were observed in more than 1,600 studies were having an impact on evolution and that human activity, in the form of urbanisation, would have a lasting legacy on life on Earth.
These findings add weight to the idea that the planet is now entering an Anthropocene epoch, a geological measurement of time in which humans are having a significant global impact on the Earth's geology and ecosystems.