Learn Turkish: Fark ettim ki yunuslar solungaç kullanmıyor. - I noticed that dolphins do not use gills.

Normally, Turkish nests clauses using participles, like Yunusların solungaç kullanmadığını fark ettim (literally: I noticed the dolphins' not-using-gills). The Persian loanword ki acts just like the English 'that', letting you link a main verb (Fark ettim) directly to an independent sentence (yunuslar solungaç kullanmıyor).

The English translation says 'do not use', but kullanmıyor has the continuous -iyor ending. Why not use the aorist (simple present) tense?

While the aorist (kullanmaz) is fine for general facts, Turkish speakers frequently use the present continuous (-iyor) to state current, ongoing realities and general habits. Both are grammatically correct here, but -iyor is very common in everyday speech even for scientific facts.

Why isn't the verb backshifted to the past tense like it often is in English (e.g., 'I noticed they didn't use gills')?

When using ki to report a realization or thought, Turkish keeps the tense exactly as it was when the thought occurred. At that moment in the past, your realization was 'Dolphins do not use gills' (present tense). Turkish preserves that original perspective rather than matching the past tense of Fark ettim.

Why is solungaç (gill) singular when dolphins obviously have multiple gills (if they had them)?