Final answer:
Angiosperms are divided into two groups based on reproductive structures: monocots, with one cotyledon, and dicots, with two. Basal angiosperms, while ancient, exhibit characteristics of both groups. The angiosperm life cycle includes a unique process called double fertilization.
Step-by-step explanation:
The two types of angiosperms based on their reproductive characteristics are monocots and dicots. These classifications are rooted in the structure of the cotyledons, which are the seed leaves within the embryonic plant. Monocots have a single cotyledon, while dicots, also known as eudicots, possess two. Other structural differences include variations in pollen grain formation and the arrangement of vascular tissue.
Basal angiosperms are an ancient lineage that split from the common ancestor of monocots and eudicots, exhibiting characteristics of both groups. Examples include the magnolias, water lilies, and star anise. Angiosperm life cycles are dominated by the sporophyte stage, and they feature a unique event called double fertilization. This process results in the formation of a diploid zygote and a triploid endosperm, which provides nutrients to the developing embryo.