how did flightless birds evolve

Flightless birds all have similar body types, Sackton noted. He said, “They all have this loss of the ‘keel’ in their breastbone that anchors flight muscles, and they have reduced forelimbs [wings], to varying degrees.” That translates to a series of convergent morphological modifications that gave rise to this common body plan in all of these species. ”.

Sackton stated, “We wanted to compare not only the regions of the genome that code for proteins, but also the regions that control when those proteins are expressed.” The team employed a method that involved aligning the genomes of over three dozen bird species, both flying and flightless, and then identifying regions that showed relatively few differences in their genetic sequence in order to identify those regions in the various species examined for the study. These conserved regions of the genome that do not form proteins most likely have a regulatory role.

“There are many steps involved in getting a limb to grow, so you can delay that process if you can knock out an enhancer and make it more difficult for those proteins to be expressed,” Sackton explained. This shows that these regions might not be able to function as enhancers because they may have lost some significant binding sites. ”.

He remarked, “If you think about it, there are a lot of ways to break something.” “A protein that isn’t expressed during a number of early stages of limb development will simply turn the system off and prevent the development of a limb.” But this is actually a complicated shift in body scaling. The fact that it’s crucial they maintain functional hind limbs constrains the system and may be the reason we observe this convergent pattern because limbs cannot just grow to different sizes at random. ”.

Researchers led by Tim Sackton, FAS Informatics Group director of bioinformatics, and Professor of Organismic and Evolutionary Biology Scott Edwards discovered that although different species exhibit significant variation in the protein-coding portions of their genomes, they appear to resort to the same regulatory pathways when evolving flight loss. This conclusion was drawn from an analysis of the genomes of over a dozen flightless birds, including an extinct moa. An article that was recently published in Science describes the study.

Johnston P. (2022). Research Outreach, 129: “Uncovering Avian Evolution: What Can We Learn From the Skeletons of Flightless Birds?” Available at: https://researchoutreach. org/articles/unearthing-avian-evolution-what-can-we-learn-from-the-skeletons-of-flightless-birds/ (Accessed YYYY/MM/DD).

The primary ecological driver of the use of smell in animals is foraging, or the search for food. Other factors that have been studied include navigation, flightlessness, social interaction, aquatic life, and nocturnality. All of these factors seem to have some effect. As our research on the relevant structures suggests, reduced dependence on other senses for foraging is also linked, from a behavioral and ecological standpoint, to increased dependence on smell.

What comes next? The results of this study allow the researchers to infer specific details about the lifestyle of these birds and the factors that influenced the evolution of particular characteristics. For instance, the fact that some of these birds had poor vision and diminished hearing may have resulted from the lack of genuine predator threats in their environments until the advent of humans, which happened to coincide with the moa extinction. In the future, the scientists will utilize the data gathered from this investigation to contrast it with results from a fresh genetic study conducted on moa and elephant birds. By analyzing the genes linked to the various functions and extracting DNA from the bones and eggshells of these extinct birds—known as “ancient DNA”—they intend to gain a deeper understanding of the role of the senses and the trade-offs between them. These anatomical and genetic studies’ combined data will enable a deeper comprehension of sensory evolution and its relationship to the competition for space inside the avian head.

Johnston, P, Mitchell, KJ, (2021) Contrasting Patterns of Sensory Adaptation in Living and Extinct Flightless Birds. Diversity, 13(11), 538. Mitchell, KJ, Llamas, B, Soubrier, J, et al, (2014) Ancient DNA reveals elephant birds and kiwi are sister taxa and clarifies ratite bird evolution. Science, 344(6186), 898–900. Johnston, P, (2011) New morphological evidence supports congruent phylogenies and Gondwana vicariance for palaeognathous birds. Zoological Journal of the Linnean Society, 163(3), 959-982.

Peter Johnston has pursued careers in clinical medicine and vertebrate anatomy research concurrently; the growing application of CT and MRI scans in anatomical research has facilitated greater collaboration between these domains. Published works feature the distinctive tuatara, kiwi, moa, and Leiopelma frogs found in New Zealand. Upcoming work features the coelacanth Latimeria.


Why are flightless bird species more likely to evolve on islands?

It is widely known that particular types birds tend to become flightless after they colonize islands that have no predators. Flightlessness has evolved over a thousand times, but it tends to evolve only from certain types of ancestors – usually birds like rails that already spend most of their time on the ground.

Do flightless birds have a common ancestor?

They found that the clade containing rheas, emus, and cassowaries had a common ancestor that lost the ability to fly, and that kiwis and elephant birds may be included in this group but also could have lost the ability to fly independently which conquers with Cubo and Wallace (2001).

How did birds evolve the ability to fly?

The cursorial hypothesis suggests that bird ancestors ran and jumped, perhaps to catch prey, and thus evolved flight as a way to enhance this, and to safely get back to the ground again.

Why did flightless birds lose their wings?

Birds probably started flying as a way to escape from enemies. Scientists tell us that some ratites may have lost the power of flight because they had no enemies. Birds living on islands without predators may not have needed to fly. Over time, they developed other ways of traveling, such as running and swimming.