Provide an explanation of the haplo-diplontic life cycles in bryophytes and pteridophytes.

(N/A) $\rightarrow$ Bryophytes and pteridophytes exhibit an intermediate condition known as the haplo-diplontic life cycle. In this cycle,both the haploid and diploid phases are multicellular,but they differ in their dominant phases.
$\rightarrow$ In bryophytes,the dominant,independent,photosynthetic,thalloid or erect phase is the haploid gametophyte. It alternates with a short-lived,multicellular sporophyte that is totally or partially dependent on the gametophyte for its anchorage and nutrition.
$\rightarrow$ In pteridophytes,the diploid sporophyte is the dominant,independent,photosynthetic,vascular plant body. It alternates with a multicellular,saprophytic or autotrophic,independent,but short-lived haploid gametophyte. This pattern of alternation between a multicellular haploid phase and a multicellular diploid phase is termed the haplo-diplontic life cycle.