water vascular system

Examples of water vascular system in the following topics:

• Phylum Echinodermata

  • Echinoderms are invertebrates that have pentaradial symmetry, a spiny skin, a water vascular system, and a simple nervous system.
  • These animals possess a true coelom that is modified into a unique circulatory system called a water vascular system.
  • The water vascular system also projects from holes in the skeleton in the form of tube feet.
  • The madreporite is a light-colored, calcerous opening used to filter water into the water vascular system of echinoderms.
  • By moving water through the unique water vascular system, the echinoderm can move and force open mollusk shells during feeding.

• Vascular Tissue: Xylem and Phloem

  • Xylem and phloem form the vascular system of plants to transport water and other substances throughout the plant.
  • The first fossils that show the presence of vascular tissue date to the Silurian period, about 430 million years ago.
  • Together, xylem and phloem tissues form the vascular system of plants .
  • The pit pairs allow water to pass horizontally from cell to cell.
  • The direction of water and sugar transportation through each tissue is shown by the arrows.

• Structural Adaptations for Land in Seedless Plants

  • Plants developed a series of organs and structures to facilitate life on dry land independent from a constant source of water.
  • In small plants such as single-celled algae, simple diffusion suffices to distribute water and nutrients throughout the organism.
  • However, for plants to develop larger forms, the evolution of vascular tissue for the distribution of water and solutes was a prerequisite.
  • The vascular system contains xylem and phloem tissues.
  • A root system evolved to take up water and minerals from the soil, while anchoring the increasingly taller shoot in the soil.

• Seedless Vascular Plants

  • Seedless vascular plants, which reproduce and spread through spores, are plants that contain vascular tissue, but do not flower or seed.
  • They contain tissue that transports water and other substances throughout the plant.
  • By the late Devonian period, plants had evolved vascular tissue, well-defined leaves, and root systems.
  • Seedless vascular plants are plants that contain vascular tissue, but do not produce flowers or seeds.
  • Although seedless vascular plants have evolved to spread to all types of habitats, they still depend on water during fertilization, as the sperm must swim on a layer of moisture to reach the egg.

• Plant Tissues and Organ Systems

  • Vascular tissue transports water, minerals, and sugars to different parts of the plant.
  • Ground tissue serves as a site for photosynthesis, provides a supporting matrix for the vascular tissue, and helps to store water and sugars.
  • Vascular plants have two distinct organ systems: a shoot system and a root system .
  • The root system, which supports the plants and absorbs water and minerals, is usually underground.
  • The root system anchors the plant while absorbing water and minerals from the soil.

• Stem Anatomy

  • The stem's anatomy consists of three tissue systems that work together to support, protect, and aid in nourishing the plant.
  • As with the rest of the plant, the stem has three tissue systems: dermal, vascular, and ground tissue.
  • The latter two types conduct water and are dead at maturity.
  • Water moves through the perforation plates to travel up the plant.
  • Sclerenchyma fibers cap the vascular bundles.

• The Evolution of Roots in Seedless Plants

  • Roots support plants by anchoring them to soil, absorbing water and minerals, and storing products of photosynthesis.
  • Nevertheless, it seems that roots appeared later in evolution than vascular tissue.
  • Plants that grow in dry areas often have deep root systems, whereas plants growing in areas with abundant water tend to have shallower root systems.
  • The vascular tissue in the root is arranged in the inner portion of the root, which is called the vascular cylinder.
  • The endodermis is exclusive to roots, serving as a checkpoint for materials entering the root's vascular system.

• The Major Divisions of Land Plants

  • Land plants, or embryophytes, are classified by the presence or absence of vascular tissue and how they reproduce (with or without seeds).
  • Plants that lack vascular tissue, which is formed of specialized cells for the transport of water and nutrients, are referred to as non-vascular plants or bryophytes.
  • Non-vascular embryophytes probably appeared early in land plant evolution and are all seedless.
  • In contrast, vascular plants developed a network of cells, called xylem and phloem, that conduct water and solutes throughout the plant.
  • Lycophytes and pterophytes are both referred to as seedless vascular plants because they do not produce any seeds.

• The Importance of Seedless Vascular Plants

  • Seedless vascular plants provide many benefits to life in ecosystems, including food and shelter and, to humans, fuel and medicine.
  • In a hostile environment, such as the tundra where the soil is frozen, bryophytes grow well because they do not have roots and can dry and rehydrate rapidly once water is again available.
  • Since bryophytes have neither a root system for absorption of water and nutrients, nor a cuticle layer that protects them from desiccation, pollutants in rainwater readily penetrate their tissues; they absorb moisture and nutrients through their entire exposed surfaces.
  • The water ferns of the genus Azolla harbor nitrogen-fixing cyanobacteria and restore this important nutrient to aquatic habitats.
  • By far the greatest impact of seedless vascular plants on human life, however, comes from their extinct progenitors.

• Diversity of Angiosperms

  • The Nymphaeales are comprised of the water lilies, lotus, and similar plants; all species thrive in freshwater biomes and have leaves that float on the water surface or grow underwater.
  • Vascular tissue of the stem is not arranged in any particular pattern.
  • The root system is mostly adventitious and unusually positioned, with no major tap root.
  • Vascular tissue forms a ring in the stem whereas in monocots, vascular tissue is scattered in the stem.
  • The root system is usually anchored by one main root developed from the embryonic radicle.