higher plants - these are species that have come to the land, and have adapted to their new habitat.There are more than 300,000 species.Higher plants are distinguished by the presence of vegetative organs such as root and shoot, and have the same photosynthetic pigments: chlorophyll and carotenoids.
higher plants mostly have a complex transport system substances can regulate the evaporation of water via the leaves.Cells of higher plants form a tissue.Sporophyte prevails in the life cycle (except bryophytes).
postpenno gametophyte is reduced to a few cells.Bodies of sexual and asexual reproduction of multicellular organisms.Fertilization with the increasing complexity of species ceases to depend on water.The zygote gives rise to a multicellular embryo.
higher terrestrial plants form the bulk of the biomass of the Earth - about 90%.
Systematics of higher plants
to higher spore plants are higher and higher seed plants.
higher spore: rinieobraznye (exclusive minerals), psilotoobraznye (store about 20 species), bryophytes (23-27 thousand species), plaunoobraznye (about 1300 species), hvoscheobraznye (about 30 species), ferns (about 12,000 species).
Higher plants that reproduce by spores, botany combine common name - higher spore.These include both currently existing and extinct species.The body of higher spore is divided into overground and underground parts, developed vegetative organs.The life cycle consists of the alternation of generations: sporophyte and gametophyte.Sporophyte well developed, lived for a long time (except bryophytes).It developed multicellular sporangia, from which, after meiosis haploid spores are formed immovable.They are single-celled, small size, spread mainly by wind and germinate in the gametophyte.
Fertilization higher spore occurs only in the presence of water.According to the location of the reproductive organs distinguish bisexual plants (which have both male and female cells) and homosexual (or are male or female cells).
Disputes may be different and the same size.Higher spore plants that have the same debate, called ravnosporovyh, and those with different arguments - heterosporous.Depending on the size distinguish microspores (small size) and megaspores (large).
believed that the seed plants came directly from Spore, particularly ferns.
higher seed plants: pinofity (gymnosperms) - about 800 species magnoliofity (angiosperms) - 300 thousand species.
higher seed plants flourished in the Mesozoic era, when the climate became more arid and cold, there was a change of seasons.Currently, the most common species of angiosperms.
seed plants have several advantages over higher spore.They consist of the same organs: root, shoot, seed.The trunk is significantly stronger than the spore, since it grow wood cells.If this is the main part of the wood cells - dead.
seed plants are extremely heterosporous.Gametophyte to sporophyte develops and eats at his expense.
reproduction occurs via seeds that are formed multicellular embryos, which include the supply of nutrients.Fertilization higher seed precedes pollination - the transfer of pollen grains to the seed beginnings of the egg.Pollination is performed by wind, water, animals, and insects.Fertilization is no longer dependent only on the water, like a higher spore.It is due to the pollen vegetative cell that grows into the pollen tube.
