1/4/2024 0 Comments Songbird speciesFeatures of songbird evolution appear to support this message. Gould argued that if the tape of life were rewound and allowed to run again from the start, chances are we would see a very different set of evolutionary outcomes. This leads to the second important conclusion: the role of chance in evolution. This colonisation of previously uninhabited regions seems to have then triggered the evolution of many new songbird species, as the group began to adapt to these novel environments and habitats. We now know that the islands of Wallacea provided the first plausible corridor out of Australia, resulting in waves of songbird expansion through Asia to the rest of the globe. Previous attempts to date the spread of the birds from Australia pointed to a much earlier time, when the landmass was isolated by thousands of kilometres of open ocean. The first is that it resolves the longstanding question of how and when songbirds arrived in Asia. These novel insights have at least three interesting implications. Maximilian Dörrbecker/Wikimedia Commons, CC BY-SA This provided the first land link between Australasia and the south-eastern tip of Asia ( Sundaland).ĭeep ocean dotted with islands separates Australia and Asia. More surprisingly, though, the first major burst of evolution within songbirds coincided with a period of tectonic collision when islands began forming in the waters north of Australia. The first songbirds originated in the landmass that would eventually become Australia. So by comparing DNA between songbird species that are related by different amounts, it is possible to reconstruct their evolutionary past and generate a family tree for the entire songbird group.īy mapping the geographic location of living species onto this family tree, the authors were then able to reconstruct where and when new songbird species evolved. Close relatives tend to have more similar DNA to each other than to distant relatives. DNA molecules are the building blocks of life and bear the imprint of our evolutionary past. To gain these novel insights, the researchers first collected DNA from many songbird species across the world. So this may explain how songbirds were able to leave Australia and radiate across the rest of the world, by island-hopping their way to Asia. This process appears to have started approximately 24m years ago, at the same time as the formation of Wallacea, a group of islands bridging the ocean-filled gap between Australia and Asia. But the most eye-catching finding is that songbirds started to spread out of Australia much more recently than previously thought. This confirmed that songbirds originated in Australia just over 30m years ago. They then linked this to information on different species’ geographic locations to understand how early songbirds spread between different continents over the course of millions of years. Using genetic and fossil data, the authors reconstructed the evolutionary “family tree” for songbirds. However, a recent study by researchers at the University of Kansas and published in the journal Nature Communications sheds new light on this question. So, despite the birds’ extensive evolutionary spread, it remained unclear how this diverse and cosmopolitan family arose from a single ancestral species on an isolated continent. Together, songbirds account for almost half of all bird species alive today.Īlthough fossils of birds are rare, the ancestor of all songbirds is thought to have originated in Australia, at a time when the Australian landmass was separated from all other land by a vast ocean in all directions. Common examples include the European robin ( Erithacus rubecula) and the North American song sparrow ( Melospiza melodia). Songbirds are a tremendously diverse group of small perching birds, made up of over 5,000 known species distributed across the world. But a new study suggests they began spreading just as the islands in and around Indonesia were being formed, creating a pathway for them to cross what had previously been thousands of kilometres of open ocean. How they managed to leave this isolated part of the world and spread all over the planet has long been a mystery to scientists. They all evolved from a common ancestor that emerged from what is now Australia around 24m years ago. The songbirds that are common in gardens all across the world have a surprisingly distant origin.
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