Gourt > Science > Biology > Flora and Fauna > Plantae > Pteridophyta
A fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta. The group is also referred to as polypodiophyta, or polypodiopsida when treated as a subdivision of tracheophyta (vascular plants). The study of ferns is called pteridology. The term pteridophytes has traditionally been used to describe all seedless vascular plants so is synonymous with "ferns and fern allies". This can be confusing given that the fern phylum Pteridophyta is also sometimes referred to as pteridophytes.
A fern is a vascular plant that differs from the more primitive lycophytes in having true leaves (megaphylls), and from the more advanced seed plants (gymnosperms and angiosperms) in lacking seeds. Like all vascular plants, it has a life cycle, often referred to as alternation of generations, characterised by a diploid sporophytic and a haploid gametophytic phase. Unlike the gymnosperms and angiosperms, in ferns the gametophyte is a free-living organism. The life cycle of a typical fern is as follows:
- A sporophyte (diploid) phase produces haploid spores by meiosis;
- A spore grows by cell division into a gametophyte, which typically consists of a photosynthetic prothallus
- The gametophyte produces gametes (often both sperm and eggs on the same prothallus) by mitosis
- A mobile, flagellate sperm fertilizes an egg that remains attached to the prothallus
- The fertilized egg is now a diploid zygote and grows by mitosis into a sporophyte (the typical "fern" plant).
Da onde que a professora tirou que ciclo de Pteridophyta é difÃcil?! Eu decorei de Gimnosperma e Angiosperma, AQUILO sim é difÃcil e enorme
__B (B.) Mon, 07 Dec 2009 23:30:24 -0000
Da onde que a professora tirou que ciclo de Pteridophyta é difícil?! Eu decorei de Gimnosperma e Angiosperma, AQUILO sim é difícil e enorme
Silica bodies and their systematic implications in Pteridaceae (Pteridophyta) http://kele.es/m6J
Sciencia (Webmaster Sciencia) Mon, 07 Dec 2009 04:01:03 -0000
Silica bodies and their systematic implications in Pteridaceae (Pteridophyta) http://kele.es/m6J
Tumbuhan lumut (bryophyta) tumbuhan paku (pteridophyta)
didiong (diah suci ) Sun, 06 Dec 2009 22:50:59 -0000
Tumbuhan lumut (bryophyta) tumbuhan paku (pteridophyta)
E essa pessoa será tão biólogo quanto nós... RT: @justgia: "Pteridophyta: uma classe de dinossauros que eram herbÃvoros."
bastosfe (felipe bastos) Sun, 06 Dec 2009 14:25:26 -0000
E essa pessoa será tão biólogo quanto nós... RT: @justgia: "Pteridophyta: uma classe de dinossauros que eram herbívoros."
Silica bodies and their systematic implications in Pteridaceae (Pteridophyta) http://kele.es/mW8
Bio_Network (George Maine) Sun, 06 Dec 2009 06:01:13 -0000
Silica bodies and their systematic implications in Pteridaceae (Pteridophyta) http://kele.es/mW8
E a pteridophyta pode ser considerada o elo entre dinossauros e aves.
justgia (justgia) Sun, 06 Dec 2009 02:44:41 -0000
E a pteridophyta pode ser considerada o elo entre dinossauros e aves.
Australian National Herbarium Fern Pages - Comprehensive information about the taxonomy and distribution of Australian region ferns and allies as well at general information about pteridophytes.
British Pteridological Society - Images and information about ferns and other pteridophytes; activities of the society including publication of the Fern Gazette, Pteridologist, and Bulletin.
Meta Description: [ Here you can find out about the BPS and its activities along with information about Ferns and other Pteridophytes ]
Checklist of World Ferns - A compiled list of the ferns and fern allies of the world, with full botanical names, information about where they are found, and their classification.
Meta Description: [ Lists all the species of ferns and fern-allies of the world. ]
Field Systematic Botany - Pteridophytes: an Overview - A detailed introduction to the ferns and fern allies.
Images of Pteridophyta - Part of the W3Tropicos database at the Missouri Botanical Garden.
Introduction to the Pteridophytes - An illustrated introduction to the ferns and fern allies for undergraduate students.
Meta Description: [ Introduction to the ferns and fern allies ]
Natural Perspective - Ferns and Allies (Filicinophyta) - Brief introduction.
Pteridophytes: Ferns and Fern Allies - Personal site with a classification scheme, bibliography, some local checklists (Ohio and Kentucky), and an article on ferns and soil conservation.
404
Pteridophytes: the Ferns and their Allies - A classification of the ferns and their allies - a work in progress at the Australian National Herbarium.
| Peru Turismo Peru | |
| Next Video | |
