BSC 196 Lecture Notes - Lecture 27: Sporangium, Endosperm, Symmetry In Biology
Document Summary
Mutualisms are common between plants and other species: many angiosperms lure insects with nectar; both plant and pollinator benefit. Some interactions only benefit the plant (ex. orchids/orchid bees) Some interactions only benefit the insect (ex. nectar robbing) Angiosperms are the most important group of plants in terrestrial ecosystems and in agriculture. Plant life cycles show alternation between sporophyte (spore-producing) and gametophyte (gamete-producing) generations. In angiosperms, the sporophyte is the plant that we see; they are larger, more conspicuous and longer-lived than gametophytes. The a(cid:374)giosper(cid:373) life (cid:272)y(cid:272)le is (cid:272)hara(cid:272)terized (cid:271)y (cid:862)three fs(cid:863) flowers: double fertilization fruits. Flowers are the reproductive shoots of the angiosperm sporophyte; they attach to a part of the stem called the receptacle. Flowers consist of four floral organs: carpels, stamens, petals, and sepals. Stamens and carpels are reproductive organs; sepals and petals are sterile. A carpel has a long style with a stigma on which pollen may land.
