cuticle

Examples of cuticle in the following topics:

• Superphylum Ecdysozoa

  • The superphylum Ecdysozoa includes the nematode worms and the arthropods, both of which have a tough external covering called a cuticle.
  • All members of this superphylum periodically molt or shed their cuticle as they grow .
  • After molting, they secrete a new cuticle that will last until their next growth phase.
  • The process of molting and replacing the cuticle is called ecdysis, which is the derivation of the superphylum's name.
  • The old cuticle splits and the insect climbs out.

• Phylum Nematoda

  • Nematodes are parasitic and free-living worms that are able to shed their external cuticle in order to grow.
  • The phyla in this group have a hard cuticle covering their bodies, which must be periodically shed and replaced for them to increase in size.
  • The cuticle of Nematodes is rich in collagen and a carbohydrate-protein polymer called chitin.
  • The cuticle also lines many of the organs internally, including the pharynx and rectum.
  • Teeth occur in some species in the form of cuticle extensions.

• Leaf Structure, Function, and Adaptation

  • A waxy layer known as the cuticle covers the leaves of all plant species.
  • The cuticle reduces the rate of water loss from the leaf surface.
  • Many aquatic plants have leaves with wide lamina that can float on the surface of the water; a thick waxy cuticle on the leaf surface that repels water.
  • A waxy cuticle covers all aerial surfaces of land plants to minimize water loss.

• Phylum Annelida

  • The epidermis is protected by an acellular, external cuticle, but this is much thinner than the cuticle found in the ecdysozoans and does not require periodic shedding for growth.
  • Chitinous hairlike extensions, anchored in the epidermis and projecting from the cuticle, called setae/chaetae are present in every segment.

• Movement of Water and Minerals in the Xylem

  • Leaves are covered by a waxy cuticle on the outer surface that prevents the loss of water.
  • Such plants usually have a much thicker waxy cuticle than those growing in more moderate, well-watered environments (mesophytes).
  • (b) A. perrottetii leaves have a waxy cuticle that prevents water loss.

• Plant Defenses Against Pathogens

  • The first line of defense in plants is an intact and impenetrable barrier composed of bark and a waxy cuticle.

• Structural Adaptations for Land in Seedless Plants

  • In land plants, a waxy, waterproof cover called a cuticle protects the leaves and stems from desiccation.
  • However, the cuticle also prevents intake of carbon dioxide needed for the synthesis of carbohydrates through photosynthesis.

• Plant Defenses Against Herbivores

  • The first line of defense in plants is an intact and impenetrable barrier composed of bark and a waxy cuticle.

• Evolution of Land Plants

  • Fossilized cells, cuticles, and spores of early land plants have been dated as far back as the Ordovician period in the early Paleozoic era.

• The Importance of Seedless Vascular Plants

  • 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.