{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Meiosis160-page5 - A pollen grain of pine tree or flower...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Meiosis and Life Cycles - 5 Alternation of Generations Most plants have both a multicellular haploid stage and a multicellular diploid stage in their life histories. This is called the alternation of generations. In plants, the structure in which meiosis occurs is called a sporangium. Meiosis does not directly produce gametes, but produces haploid cells, called spores that in turn, grow, by mitosis, into multicellular haploid structures called gametophytes (gamete-making plant). Gametophytes eventually produce and contain gametes. (The multicellular diploid structures that produce sporangia are called sporophytes.) Which stage (sporophyte or gametophyte) is predominant in the life of a plant varies with different types of plants. Most "higher" plants have predominant sporophytes.
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: A pollen grain of pine tree or flower, for example is the male gametophyte stage of those plants. In ferns, both gametophyte and sporophyte are photosynthetic, but the gametophyte is short-lived and very small. Mosses, in contrast, have predominant gametophyte stages. Alternation of Generations in Plants Fern Sporangia Fern Gametophyte Non-Sexual Reproduction As discussed, many organisms have both sexual and non-sexual means of increasing the numbers of individuals. Asexual reproduction can be a good strategy in an environment that is consistent, if a species is well suited to those conditions. Without sexual reproduction, however, there is no genetic variation to adapt to change....
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern