Rabu, 12 September 2012

gymnospermae


 ESSAY :                                                       GYMNOSPERM    

                    Gymnosperm means naked seed . a gymnosperm seed is “naked” because it lacks a protective fruit covering . such as the pulpy fruit tissue around apple seeds . gymnosperms include cycads, ginkgoes, and conifers. Cycads include only a few surviving species that live in tropical or warm temperature zone. Numerous species of cycads flourished during earlier when dinosaurus dominated the earth . a cycad looks like a small palm tree , but cycads produce large , seed bearing , conelike structure then ginkgoes are deciduous wich means thah the leaves are shed each year. And conifers get their name from the fact that they bear their seeds in cones . the are by far the most varied and widely distributed gymnospermae.
                    Life cycle of a gymnosperms the sporophyte is large, while the gametophyte consist of only a few cells . the life cycle in cycads and ginkgoes is similar to that in conifers , but the structures that produce seeds are foun on sparate plants from the structure that produce poken.
example life cycle gymnos :


Tidak ada komentar:

Posting Komentar