Abstract All land plants are believed to have had their origin in a unicellular green algal ancestor. Filme Eu Tu E Eles Movies more. The major innovations in the evolution of early land plants from their primitive ancestors were, not surprisingly, adaptations that allowed plants to reproduce in the absence of water. Besides a more sophisticated and differentiated multicellular anatomy, the invention of new reproductive structures and strategies were fundamental for the success of terrestrial colonization. One of the key innovations in the life history of land plants was the emergence of a haplo‐diplontic life cycle, in which an asexual diploid phase, the sporophyte, is predominant over a reduced and dependent sexual haploid phase, the gametophyte.

Other evolutionary trends include a transition to a heterosporic life cycle, internalization of gametes within specialized gametophytes, development of a pollination mechanism independent of water for fertilization, and the invention of seeds, an efficient way of protecting and dispersing the developing embryos. Key Concepts: • Paleobotany and phylogenetic analyses are important tools for inferring trends in the evolution and diversification of plants. Motivewave 3.4.2 Ultimate Edition Crack. • Land plant evolution involved innovations which allowed organisms to reproduce without a need for water. • Sporophytes are believed to have evolved from a haploid ancestral condition in which meiosis was delayed. • Multicellularity and sexual reproduction allowed diversification and adaptation to new environments during evolution. • Meiosis is essential in a sexually reproducing organism for maintenance of ploidy after fertilization. • Fertilization generates genetic diversity by combining chromosomes inherited from two distinct individuals.

• Endospory evolved in the production of a seed. • Heteromorphism allowed evolution of sexual dimorphism. • Apomixis allows clonal propagation by seeds. Keywords: meiosis; gamete; zygote; haploid; diploid; apomixes. Life cycle of a green alga, Ulva. The sporophyte and gametophyte are multicellular and look identical (isomorphic).

The gametophyte and sporophyte are both two cell‐layers thick. Cells on the sporophyte undergo meiosis and produce two types of spores, + and −. Each spore divides mitotically to give rise to a gametophyte (either + or −). The gametophyte produce (+) and (−) gametes. A (+) gamete fuses with a (−) gamete and forms the zygote.

Gametophyte and Sporophyte. Moss sperm are produced from cells in the antheridia of the male gametophyte. The moss eggs are located at the base of the. Define sporophyte: the diploid multicellular individual or generation of a plant with alternation of generations that begins from a diploid zygote. More Sporophyte And Gametophyte Moss videos. Start studying BJU Chapter 13 flashcards. Describe the gametophyte and the sporophyte of a. How are the life cycles of a fern located and a moss.