Ecology and evolutionary biology is an interdisciplinary field of study concerning interactions between organisms and their ever-changing environment, including perspectives from both evolutionary biology and ecology. This field of study includes topics such as the way organisms respond and evolve, as well as the relationships among animals, plants, and micro-organisms, when their habitats change. Ecology and evolutionary biology is a broad field of study that covers various ranges of ages and scales, which can also help us to comprehend human impacts on the global ecosystem and find measures to achieve more sustainable development. Examples of current research topics Birdsong There is a number of acoustic research about birds. Birds learn to sing in specific patterns because birdsong conveys information to select partners, which is a result of evolution. However, this evolution is also affected by ecological factors. Research with recorded birdsong of male white-crowned sparrows from different regions found that the birdsongs from the same location have the same traits, while birdsongs from different locations are more likely to have different song types. Birdsongs from areas with dense vegetation tend to only have slow trilling sounds and low frequencies, while birdsongs from more open areas have fast trilling sounds and higher frequencies. This is probably due to differences in the propagation of sound through vegetation. Low frequencies can be heard from further away when going through dense vegetation than high frequencies. For that reason it would be an advantage for birds who live in dense vegetation to sing at lower frequencies. That way, their songs can still be heard by competitors and potential mates far away. Something similar was found in birds living on a mountain. The birds who lived higher up were singing at higher frequencies. This was probably due to the higher parts of the mountain being colder and therefore fewer other species living there. Other animals also make sounds with which the birds would have to compete, so when there are less species, there are less high frequency sounds to compete with. Snail colour The colour and ornamentation of the snails’ shells are almost entirely determined by their genes. One kind of land snail, Cepaea nemoralis, which is very common in Europe, has been studied and found to have a few different colours and a different amount of dark bands on their shells. In a large citizen science project ‘the Evolution Mega-Lab’, citizens of many different countries