How does the "alternation of generations" in gymnosperm adopt for survival in a land environment?example: Pollen's wing like structure-Adaptation that enables the pollen to be easily dispersed by...

How does the "alternation of generations" in gymnosperm adopt for survival in a land environment?

example: Pollen's wing like structure-Adaptation that enables the pollen to be easily dispersed by the wind.

Asked on by timid1995

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bandmanjoe | Middle School Teacher | (Level 2) Senior Educator

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The alternation of generations is a process plants use in their life cycles which allows them to procreate using both sporophytes and gametophytes.  This basically gives them a two-pronged approach at reproduction, which is not available to all animal and plant species.  Plants start with two gametes, which are already at a haploid chromosome count.  The resulting zygote has a diploid chromosome count and develops into a mature plant.  The diploid plant produces spores by the meiosis process which reduces the chromosome count by one-half, making the spores haploid again.  The spores sprount and mature into plants using the mitosis process.  The choromsome count is already haploid, so the production of gametes with haploid chromosome counts takes place, and we have made full circle, back where we started. 

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