A Closer Look at Plant Reproduction, Growth, and Ecology

A Closer Look at Plant Reproduction, Growth, and Ecology — page 9
A CLOSER LOOK AT PLANT REPRODUCTION GROWTH AND EcoLOGY sexual reproduction is a process that increases variation among offspring ALTERNATION OF GENERATIONS In plants the process of sexual reproduction takes place in two distinct phases or genera tions In one phase the organism reproduces by means of spores and in the other by means of sex cells This reproductive pattern is called alternation of generations The structure that produces spores is known as the sporophyte Spores are single cells that like the gametes of animals are produced by a type of cell division called meiosis When a spore germinates it pro duces the gametophyte the structure that produces gametes When a male gamete or sperm unites with a female gamete or egg they form the zygote The alternation of generations is perhaps most clearly seen in ferns because the spo rophyte and gametophyte form independent structures The common fern fronds that grow along stream banks are sporophytes They produce spores in structures called sori which are often found on the underside of the plant's leaves When a released spore lands at a place favorable for germination it grows I