basal taxon

Examples of basal taxon in the following topics:

• Phylogenetic Trees

  • A lineage that evolved early from the root and remains unbranched is called basal taxon.
  • For example, if a branch point was rotated and the taxon order changed, this would not alter the information because the evolution of each taxon from the branch point was independent of the other.
  • A lineage that evolved early and remains unbranched is a basal taxon.

• The Levels of Classification

  • The name at each level is also called a taxon.
  • Carnivora is the name of the taxon at the order level; Canidae is the taxon at the family level, and so forth.

• Double Fertilization in Plants

  • The zygote divides to form two cells: the upper cell (terminal cell) and the lower cell (basal cell).
  • The division of the basal cell gives rise to the suspensor, which eventually makes connection with the maternal tissue.
  • After fertilization, the zygote divides to form an upper terminal cell and a lower basal cell.
  • The basal cell also divides, giving rise to the suspensor.

• Brain: Midbrain and Brain Stem

  • Interconnected brain areas called the basal ganglia (or basal nuclei) play important roles in movement control and posture.
  • Damage to the basal ganglia, which occurs in Parkinson's disease, leads to motor impairments such as a shuffling gait when walking.
  • The basal ganglia also regulate motivation.
  • For example, when a wasp sting led to bilateral basal ganglia damage in a 25-year-old businessman, he began to spend all his days in bed and showed no interest in anything or anybody.

• Diversity of Angiosperms

  • Basal angiosperms are a group of plants that are believed to have branched off before the separation into monocots and eudicots because they exhibit traits from both groups.
  • The Magnoliidae (magnolia trees, laurels, and water lilies) and the Piperaceae (peppers) belong to the basal angiosperm group .
  • Examples of basal angiosperms include the Magnoliidae, Laurales, Nymphaeales, and the Piperales.

• Building Phylogenetic Trees

  • If a characteristic is found in the ancestor of a group, it is considered a shared-ancestral character because all of the organisms in the taxon or clade have that trait .

• Evolution of Angiosperms

  • Paleobotanists debate whether angiosperms evolved from small woody bushes, or were basal angiosperms related to tropical grasses.
  • A few other angiosperm groups, known as basal angiosperms, are viewed as primitive because they branched off early from the phylogenetic tree.
  • Basal angiosperms, such as water lilies, are considered more primitive because they share morphological traits with both monocots and eudicots.

• Contractile Vacuoles in Microorganisms

  • Structure of Euglena: 1 - Flagellum; 2 - Eye spot / Pigment spot / Stigma; 3 - Photoreceptor; 4 - Short second flagellum; 5 - Reservoir; 6 - Basal body; 7 - Contractile vacuole; 8 - Paramylon granule; 9 - Chloroplasts; 10 - Nucleus; 11 - Nucleolus; 12 - Pellicle

• Animal Bioenergetics

  • Metabolic rate is estimated as the basal metabolic rate (BMR) in endothermic animals at rest and as the standard metabolic rate (SMR) in ectotherms.

• Hormonal Regulation of Metabolism

  • The basal metabolic rate, which is the amount of calories required by the body at rest, is determined by two hormones produced by the thyroid gland: thyroxine, also known as tetraiodothyronine or T4, and triiodothyronine, also known as T3.