flightless bird
Học thuậtThân thiện
Definition
Noun: A flightless bird is a type of bird that is naturally unable to fly due to evolutionary adaptations. These birds typically have flat breastbones (sternums) that lack a keel, which is the ridge where powerful flight muscles would attach in flying birds.
Usage
The term is used to categorize and describe specific bird species that have lost the ability to fly over time. * Ostriches, emus, and kiwis are all examples of flightless birds. * The study focused on the evolution of flightless birds on isolated islands. * Penguins are often considered flightless birds, though their wings are adapted for swimming.
Advanced Usage
- In evolutionary biology: The term is used to discuss convergent evolution, where unrelated bird groups in different parts of the world (like ostriches in Africa and rheas in South America) independently evolved flightlessness.
- In paleontology: It refers to extinct species, such as the moa or the elephant bird, highlighting how flightlessness could make species vulnerable to extinction after human arrival.
Variants and Related Words
- Ratite (noun): This is the formal biological term for the group of large, flightless birds with a flat, raft-like breastbone (from Latin , meaning "raft"). Not all flightless birds are ratites (e.g., penguins), but the core examples like ostriches and emus are.
- Flightlessness (noun): The condition of being unable to fly.
Synonyms
- Non-volant bird (formal/scientific)
- Ratite (for the specific major group)
Different Meanings
The term "flightless bird" has a single, specific zoological meaning and is not used idiomatically. It does not function as a phrasal verb.
Noun
- flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds