Flashcards in EHOF- The Colonization of Land Deck (46)
What are charophytes?
-Closest relative of land plants
What are some adaptations that have enabled a move to land for plants?
-In charophytes, a layer of polymer called sporopollenin prevents expose zygotes from drying out
-Adaptations for a shallow water life
-New environmental opportunities include unfiltered sunlight, CO2 and soil nutrients and few herbivores/pathogen's
What are the three shared, derived traits of plants?
1.Alternation of generations with multicellular dependent embryos
2.Wild spores produced in sporangia
What are the dependent embryos?
The zygote is retained in female plant tissue and the parent provides nutrients
What are the two additional derived traits of plants?
-Cuticle which is a waxy covering of the epidermidis
-Stomata which have specialized pores for gas exchange and can close in hot, dry conditions to minimize water loss
What are the nutritional and fungal lifestyles?
-Fungi are heterotrophs but do not ingest their food
-They secrete exoenzymes into their surroundings that break down complex molecules and then absorb the remaining smaller compounds
What are mycorrhizae?
-Mutually beneficial relationships between fungi and plant roots
-Ectomycorrhizal fungi Form sheets of hyphae over a root and grow into the extracellular space of the root
-Arbuscular mycorrhizal fungi extend the hyphae Through the cell walls of root cells and into tubes for me by invagination of the root cellular membrane
What is the origin of fungi?
-DNA evidence suggests that most fungi are closely related to unicellular nucleariids and animals are more closely related to unicellular choanoflagellates
What are some elements of the morphology of mushrooms?
-Mycelia are networks of branch to be adapted for absorption
-Most fungi have cell walls made of chitin not cellulose
-Their surface to volume ratio enhances feeding efficiency
What are haustoria?
Some fungi have specialized hyphae called haustoria that allow them to penetrate the tissues of their host
What are chytrids?
-They are found in freshwater and terrestrial habitats and can be decomposers, parasites or symbionts
-They have flagellated spores called zoospores
What are zygomycetes?
They are named for their sexually produce zygosporangia
What are zygosporangia?
-They are resistant to freezing and drain meaning they can persist through unfavourable conditions
-Once the conditions improve they undergo karygomy
What are glomeromycetes?
-Once considered zygomycetes
-They form a distinct type of endomycorrhizae called arbuscular mycorrhizae
What are ascomycetes?
-Are defined by production of sexual spores in saclike asci which are usually contained in fruiting body is called ascocarps
-Reproduce asexually by enormous numbers of asexual spores call conidia Produced at conidiophores
What are bascomycetes?
-Defined by a club like structure called a basidium, a transient diploid stage in the lifecycle
-The lifecycle of a basidiomycete usually include a long lived dikaryotic mycelium
What are nonvascular plants called?
What was the prevalent vegetation for the first 100 million years of plant evolution?
Bryophytes and bryophyte-like plants. Vascular plants began to diversify during the Carboniferous period
What are living vascular plants classified by?
-Lifecycles with dominant sporophytes
-Vascular tissues called xylem and phloem
-Well developed roots and leaves
What is the difference between sporophytes and gametophytes?
-Sporophytes are diploid and are the larger generation
-Gametophytes are tiny plants that grow on or below the soil surface
What is the difference between xylem and phloem tissues?
Xylem tissues conduct most water and minerals
Phloem tissues distribute sugars, amino acids, and organic products via living cells
What is the difference between roots and leaves?
Roots are organs to anchor the vascular plants and absorb water and nutrients from the soil. Leaves increase surface area to capture more solar energy for photosynthesis
What is the difference between microphylls and megaphylls?
Microphylls are leaves with a single vein and megaphylls are leaves with a highly branched vascular system
What are seed plant traits?
-Ovules and pollen
What are reduced gametophytes?
-Are usually microscopic and develop within walls of spores, retained inside tissues of the parents sporophyte
-Protection from UV radiation, drying out and gametophyte gets nutrients from parent sporophyte
What is an ovule?
Megasporangium, megaspore and protective integuments
What is the difference between gymnosperm megaspores and angiosperm megaspores?
Gymnosperm megaspores have one integument and angiosperm megaspores have two integuments
What develops into pollen grains?
Microspores which contain the mail gametophytes and are protected by sporopollenin
What is pollination?
The transfer of pollen to the parts of a seed plant containing ovules