Question

The adult plant body in bryophytes is haploid while in pteridophyte it is diploid. why ?Give reason.

Answer 1

Since the pteridophytes are the next group in series after bryophytes, it so happened. If a theory is to be put forwarded in this regard, one can point out that producing spores as the progenitors of the next generation directly by the adult plant body i.e a sporophyte is more economical than producing the gametes. Moreover the sex determination evolves with heterothallic species in pteridophytes.