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Difficulty: MediumThallophytes, Bryophytes, and Pteridophytes

During plant evolution, non-seed bearing plants (cryptogams) exhibit important structural and developmental transitions. Which structural feature uniquely characterizes mature pteridophytes when compared to bryophytes?

  1. A dominant, independent sporophyte generation containing true vascular tissueAnswer
  2. B
    A dominant gametophyte generation supported by lignified vascular bundles
  3. C
    The reliance on xylem for bidirectional translocation of synthesized organic food
  4. D
    An extracellular saprophytic mode of nutrition for obtaining organic matter

Answer

Pteridophytes are distinguished from bryophytes by having a dominant, free-living sporophyte generation that possesses true vascular tissues (xylem and phloem).
The correct response highlights the evolutionary innovation of pteridophytes: they possess a dominant, multicellular, free-living sporophyte equipped with lignified vascular tissues (xylem and phloem) for water and nutrient conduction.

Step-by-Step Solution

1
Compare the dominant generation between bryophytes and pteridophytes.
Bryophytes have a dominant gametophyte stage, whereas pteridophytes have a dominant sporophyte stage.
Plant kingdom evolution progresses from gametophyte-dominated life cycles to sporophyte-dominated life cycles.
2
Evaluate the presence of internal conducting tissues in both groups.
Bryophytes lack vascular tissues (tracheophytes), whereas pteridophytes are vascular plants equipped with xylem and phloem.
Lignified vascular tissue evolved in pteridophytes, allowing them to achieve larger physical size and structural support compared to non-vascular bryophytes.

Key Concept

Structural differentiation and life cycle dominance in cryptogamic plant divisions
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Topics

Thallophytes, Bryophytes, and Pteridophytes

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