In family Asteraceae, the presence of which of the following character...
Phylogenetically Primitive Character in Family Asteraceae
Family Asteraceae is one of the largest and most diverse families of flowering plants, commonly known as the aster, daisy, or sunflower family. The family comprises about 32,000 species of herbs, shrubs, and trees distributed worldwide. The family is characterized by several unique morphological features such as head inflorescence, involucre of bracts, inferior ovary, and unisexual florets. Among these characters, the presence of five stamens in disc florets is considered phylogenetically primitive for the family.
Explanation
Phylogenetically primitive characters are those traits that are present in the ancestral group and are retained in the descendants, without any significant modification. In contrast, phylogenetically advanced characters are those that have evolved later and are present only in the descendants, not in the ancestral group. In the family Asteraceae, the presence of five stamens in disc florets is considered phylogenetically primitive because:
- The ancestral group of Asteraceae is believed to have had five stamens per flower. This is evident from the fossil record of the family's ancestors, which show the presence of five stamens in the flowers.
- Most of the other character states of Asteraceae are considered derived, meaning they have evolved from the ancestral state. For example, the head inflorescence, involucre of bracts, and inferior ovary are unique to the family and have evolved from the ancestral condition of open inflorescence, lack of involucre, and superior ovary, respectively.
- The reduction of stamens from the ancestral condition of five to fewer has occurred independently in several lineages of Asteraceae. For example, some tribes of the family, such as Heliantheae and Inuleae, have four stamens, while others, such as Anthemideae and Gnaphalieae, have three or fewer stamens.
Therefore, the presence of five stamens in disc florets is considered a phylogenetically primitive character in the family Asteraceae.
In family Asteraceae, the presence of which of the following character...
Correct answer is option 'D'
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