<P> Alternation of generations is defined as the alternation of multicellular diploid and haploid forms in the organism 's life cycle , regardless of whether or not these forms are free - living . In some species , such as the alga Ulva lactuca , the diploid and haploid forms are indeed both free - living independent organisms , essentially identical in appearance and therefore said to be isomorphic . The free - swimming , haploid gametes form a diploid zygote which germinates into a multicellular diploid sporophyte . The sporophyte produces free - swimming haploid spores by meiosis that germinate into haploid gametophytes . </P>
<P> Alternation of generations is defined as the alternation of multicellular diploid and haploid forms in the organism 's life cycle , regardless of whether or not these forms are free - living . In some species , such as the alga Ulva lactuca , the diploid and haploid forms are indeed both free - living independent organisms , essentially identical in appearance and therefore said to be isomorphic . The free - swimming , haploid gametes form a diploid zygote which germinates into a multicellular diploid sporophyte . The sporophyte produces free - swimming haploid spores by meiosis that germinate into haploid gametophytes . </P>
in alternation of generations a diploid sporophyte goes through meiosis to form
in alternation of generations a diploid sporophyte goes through meiosis to form
haploid gametophytes
haploid gametophytes