B2 Flashcards
What are some characteristics of vascular plants?
Apical meristems which cause primary growth, occurring at the tips of shoots and roots, producing new leaves and flowers.
Lateral meristems which cause secondary growth, occurs at the cambium, produces bark
What are the two types of vascular plants?
Seedless vascular plants and vascular plants that produce seed
What is the sporophyte generation?
Dominant generation which lives independently from the gametophyte which is usually small and inconspicuous. Sporophyte has apical meristem and is usually branched. Sporophyte has vascular conducting tissue with xylem and phloem. Presence of cuticle, stomata and lignified tissue in vascular plants.
What is the classification of seedless vascular plant?
Rhyniophyta - fossils
Zosterophyllophyta - fossils
Trimerophytophyta - fossils
Psilophyta - extant primitive fern relatives
Lycophyta - club mosses
Sphenophyta - horsetails
Pterophyta - true ferns
What were the earliest vascular plants?
Simple, 400Ma, rhyniophytes, upright, leafless, dichotomously branched stems, sporangia produced at ends of branches. Very simple vascular bundles, epidermis with cuticle, homosporous.
What are psilophyta?
Simplest, extant vascular plants. Psilotum has no roots or leaves. Upright stem is branched with small scales, sporangia are produced on the ends of branches. Gametophyte is unique among vascular plants because it has a vascular system.
Where is psilotum found.
Tropical and subtropical areas
What are pterophyta?
360Ma, 11,000 species so are largest group of seedless vascular plants. Diverse in form. Great diversity in tropics, many are epiphytes. Less species in temperate regions. Most are homosporous, most temperate forms have a rhizome and produce new sets of leaves yearly. Adventitious roots produced from the rhizome.
What do fern leaves contain?
Petiole (stalk) and lamina (leaf). Rachis midleaf.
What are rhizomes?
Underground stems
What are fern sporangia?
Formed by the sporophyte generation, produced on underside in clusters called sorus, which is often covered by an indusium. Other ferns produce two types of leaves one vegetative (no sporangia) and one fertile (sporangia)
What is the life cycle of a fern?
Diploid -> meiosis -> haploid
What are sphenophyta (horsetails)?
Giant horsetails were part of the Carboniferous flora. Modern horsetails are much smaller. Underground rhizome which bears adventitious roots and aerial stems. Stems ornamented with silica nodules. Sporangia are produced in strobili.
What are lycophyta?
Extant members of this group include lycopodium and selaginella. Extinct members included the lycophyte trees that dominated the steamy swamp forests of the Carboniferous period, oldest extant group of vascular plants. Dominated major habitats for 40 million years.
What are selaginella?
Resurrection plant, heterosporous
What happens in the life cycle of a fern?
Spore dispersal, spore, young gametophyte, mature gametophyte, archegonium, sperm, archegonium, egg, zygote, gametophyte, new sporophyte, mature sporophyte, fiddlehead, sporangium, sorus, sporangium
What is a disadvantage of the fern life cycle?
New sporophyte is temporarily dependent on a tiny gametophyte at the start of its life. Many new sporophytes perish, would be advantageous if the sporophyte embryo could derive nourishment from the mother sporophyte.
How would survival of the young sporophyte be increased?
For sporophyte embryo to derive nourishment from the mother sporophyte, the female gametophyte has to be retained inside the mother sporophyte. It develops within the sporangium, microspores have to be carried to the megagametophyte in pollen.
