Other meanings of Angiosperms
Botany
Angiosperms, or flowering plants, are the most diverse group of land plants, comprising about 300,000 known species. They are distinguished by their ability to produce flowers and fruits, which enclose and protect the seeds. This reproductive strategy has allowed them to dominate most terrestrial ecosystems since the Cretaceous period.
Angiosperms are vascular seed plants in which the ovules (and later seeds) are enclosed within a carpel, a structure that develops into a fruit. This enclosure distinguishes them from gymnosperms, whose seeds are naked. The flower, typically composed of sepals, petals, stamens, and carpels, is the reproductive structure unique to angiosperms. Double fertilization, a process in which one sperm fertilizes the egg and another fuses with polar nuclei to form endosperm, is another hallmark. These features have enabled angiosperms to occupy a vast range of habitats, from aquatic to arid, and to coevolve with a wide array of pollinators and seed dispersers.
Angiosperms first appear in the fossil record during the Early Cretaceous, about 140 million years ago, but molecular clocks suggest an earlier origin in the Jurassic. Their rapid diversification during the mid-Cretaceous, often termed the "Cretaceous Terrestrial Revolution," coincided with the rise of insect pollinators and led to the replacement of gymnosperm-dominated forests. The earliest diverging lineages include Amborella trichopoda, water lilies, and star anise, which retain ancestral traits. Subsequent radiations produced the monocots and eudicots, which together account for the vast majority of living species. This evolutionary success is attributed to innovations such as efficient water transport, flexible growth forms, and coevolution with animals.
Modern classification, based on molecular phylogenetics (notably the APG system), divides angiosperms into several major clades. The basal angiosperms include Amborella, Nymphaeales (water lilies), and Austrobaileyales. Magnoliids form a separate clade that includes magnolias, laurels, and black pepper. Monocots, characterized by a single cotyledon and parallel-veined leaves, include grasses, orchids, and palms. Eudicots, with two cotyledons and net-veined leaves, are the largest group, encompassing roses, sunflowers, oaks, and most familiar flowering plants. The APG IV system recognizes 64 orders and about 416 families, providing a stable framework for research and conservation.
Beyond the familiar, angiosperms exhibit remarkable extremes. The smallest flowering plant, Wolffia, is a rootless aquatic duckweed less than a millimeter long, while the largest flower, Rafflesia arnoldii, can exceed one meter in diameter and emits a rotting-flesh odor to attract flies. Some angiosperms are parasitic, such as the mistletoe and the underground plant Hydnora, which lacks chlorophyll entirely. Others are carnivorous, like the Venus flytrap and pitcher plants, supplementing nutrient-poor soils with insects. The longest-lived angiosperm, a clonal colony of seagrass in the Mediterranean, is estimated to be over 100,000 years old. These examples highlight the extraordinary adaptability of flowering plants to nearly every ecological niche on Earth.
Angiosperms are the dominant plant group on Earth, providing food, medicine, and habitat for countless organisms.
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