https://www.researchgate.net/publication/380972076_Modern_dinosaursbirds_are_dinos_but_NOT_pterodactyls
The conjecture that the first birds were flightless has been a topic of significant interest in paleontology and evolutionary biology. Here's a brief summary of the arguments and evidence related to this idea:
### Arguments for Flightless Ancestry:
1. **Fossil Evidence:**
- **Archaeopteryx**: Often cited as one of the earliest known birds, Archaeopteryx had features suggesting it was capable of some form of flight. However, some analyses propose it might have been more adapted to gliding or limited flight.
- **Early Avialans**: Other early bird-like dinosaurs, such as certain members of the group Avialae, show a mixture of traits, some of which may indicate a flightless lifestyle. For instance, *Anchiornis* and *Xiaotingia* had well-developed feathers but their flight capability remains debated.
2. **Evolutionary Pathways:**
- The transition from non-avian theropods (a group of bipedal dinosaurs) to birds involves a gradual acquisition of flight-related adaptations. It's plausible that early members of this lineage were not fully capable of powered flight but used their feathers for other purposes like insulation, display, or gliding.
3. **Functional Morphology:**
- The anatomy of early birds and their close relatives often includes features that are not solely associated with flight. These could suggest adaptations for other activities, such as running, climbing, or gliding.
### Arguments Against Flightless Ancestry:
1. **Flight Adaptations:**
- Discoveries of well-preserved fossils, such as *Microraptor*, show that some early bird-like dinosaurs had adaptations for aerial locomotion, indicating that flight, or at least aerial capability, evolved early in the avian lineage.
2. **Complexity of Flight Evolution:**
- The development of flight is a complex process that likely involved multiple stages. Some scientists argue that the presence of flight adaptations in many early birds suggests that flight capability was a driving force in their evolution.
### Synthesis and Current Understanding:
The current consensus in the scientific community tends to favor a model where early avians evolved from small, feathered theropods that gradually developed the ability to fly. This implies that while the very first birds may not have been capable of sustained powered flight, they likely possessed some form of aerial capability, whether through gliding or short bursts of flapping flight.
Thus, while it's not entirely accurate to say that the first birds were completely flightless, it's reasonable to suggest that the earliest members of the avian lineage were not adept fliers and that full-fledged powered flight evolved later in their evolutionary history.
We can never know, but many present day birds here in New Zealand are flightless :)
What counts as a bird? If feathers are a sine qua non, then it's not inconceivable that some early featherless flying critters evolved into feathered flying critters, in which case their birdhood evolved after the capacity for flight. Note that I said "some". The evolution of birds might have taken several paths with different sequences from a common nonbird ancestor (and it obviously also makes a difference which nonbird ancestor is chosen as the common one).
- Badges
- Science topic
- Similar topics
- Computer Science
- Research Topics