This is the 444th most frequent German word.
sogenannte
"Called" or "so-called."
In this sentence, 'sogenannte' is used sarcastically to question the expertise of the individual referred to as an expert.
Der sogenannte Experte hat einen gravierenden Fehler gemacht.
The so-called expert has made a grave error.
Here, 'sogenannte' is used to indicate that the term 'symbiosis' needs closer examination or is not used in its strict scientific sense.
Diese Tiere leben in einer sogenannten Symbiose.
These animals live in a so-called symbiosis.
In this sentence, 'sogenannte' simply introduces a name or label by which the subject is commonly referred to without additional nuance.