Evolutionary Process Of Omnivorous Birds

Omnivorous birds put their eggs in one basket

A latest research published in Nature produced astonishing results – Birds that are omnivorous have lower diversification rates – higher risks of extinction and are less likely to evolve to different species

Few studies had been done to establish the connection between diet and evolutionary processes. A study conducted recently on birds obtained critical information showing the links between diet and evolution. The surprising results will have deep repercussions in the field of Biology. It can possibly be the key to unlock the secrets of why some species goes extinct and why some diverge into different species.

What an organism eats is associated to how it interacts with its environment. The diet

After new techniques were developed and more information was made available, the study led by Gustavo Burin from Department of Ecology, University of São Paulo, aim to explicitly prove the effect of diet on evolutionary processes. The evolutionary processes they focused on are extinction and speciation in which birds separate to form new and different species and transition in which birds change their diet category. Birds were chosen as their main model of study due to the large and orderly classified diversity of birds and vast sources of information available. Furthermore, birds show many distinct and varied behaviour and life processes.

Some birds only feed on a certain type of food and are known as specialized feeders. Some examples of specialized feeders are insectivores- only feed on insects, frugivores---fruit eaters, seed predators--- eat seeds, carrion-feeders ---feed on dead and decaying flesh. Generalized feeders will have a generalized diet in which they feed on a variety of food types, including insects, fruits, seeds and carrion. Birds have varying physical and chemical functions to deal with eating different foods. Researchers believed that different diets will result in diverse speciation, extinction and transition

For instance, omnivorous birds feeding on insects and fruits would have their diet overlapping with insectivores and frugivores. Yet, birds feeding on insects would not have any overlap with other birds feeding on food types like fruits and seeds. Thus, omnivores will face much competition from the specialist birds no matter what food they choose to feed on. It may be commonly expected that omnivores will have advantage over specialists since omnivores have more food choices compared to specialists which can only sustain life with a single type. However, this is far from the truth. In most cases, resources are fairly stable and constantly available. Since omnivores share their resources with various specialists, in the long run, they lose out due to competition for the same food when they are less competent at doing so. As a result, there is a low variety of generalist species and higher extinctions.

As omnivores face high extinction rates, they may not have sufficient time to undergo speciation and form 2 different species before they go extinct. However, omnivores have not completely vanished due to high transition rates into omnivory. This would only occur when there is low availability of a preferred food source. For instance, an herbivore will only eat plants. Yet, when there are a low number of plants in the environment, herbivorous birds that can also take other food