whorl

Examples of whorl in the following topics:

• Genetic Control of Flowers

  • This switching is necessary for each whorl to obtain its final unique identity.
  • In the first floral whorl only A-genes are expressed, leading to the formation of sepals.
  • In the second whorl both A- and B-genes are expressed, leading to the formation of petals.
  • For example, when there is a loss of B-gene function, mutant flowers are produced with sepals in the first whorl as usual, but also in the second whorl instead of the normal petal formation.
  • In the third whorl the lack of B function but presence of C-function mimics the fourth whorl, leading to the formation of carpels also in the third whorl .

• Angiosperm Flowers

  • A whorl of sepals (collectively called the calyx) is located at the base of the peduncle and encloses the unopened floral bud.
  • Petals, collectively the corolla, are located inside the whorl of sepals and often display vivid colors to attract pollinators.

• Leaf Structure and Arrangment

  • Leaves are classified as either alternate, spiral, opposite, or whorled.
  • If there are three or more leaves connected at a node, the leaf arrangement is classified as whorled.

• Sexual Reproduction in Angiosperms

  • A typical flower has four main parts, or whorls: the calyx, corolla, androecium, and gynoecium .
  • The outermost whorl of the flower has green, leafy structures known as sepals, which are collectively called the calyx, and help to protect the unopened bud.
  • The second whorl is comprised of petals, usually brightly colored, collectively called the corolla.
  • The third whorl contains the male reproductive structures and is known as the androecium.
  • If all four whorls are present, the flower is described as complete.

• Transduction of Sound

  • The cochlea is a whorled structure, like the shell of a snail, and it contains receptors for transduction of the mechanical wave into an electrical signal.
  • The mechanical properties of the basilar membrane change along its length, such that it is thicker, tauter, and narrower at the outside of the whorl (where the cochlea is largest), and thinner, floppier, and broader toward the apex, or center, of the whorl (where the cochlea is smallest).

• Ferns and Other Seedless Vascular Plants

  • Leaves and branches come out as whorls from the evenly-spaced joints.

• Diversity of Angiosperms

  • Veins form a network in leaves, while flower parts come in four, five, or many whorls.