Division Coniferophyta comprises the conifers, the most abundant gymnosperms today. Conifers are trees or shrubs that bear their seeds in cones, without the protection of a fruit as the angiosperms have. The cones contain all of the plant's reproductive structures. Like most plants, conifers have a life cycle following an alternation of generations pattern.

The diploid generation, the sporophyte, is the plant itself, while the haploid generations, or gametophytes, are microscopic stages inside the cones. There are two types of cones on a conifer: the large, female cones that contain many ovules, which will produce the female gametophytes, and the much smaller, male cones, which produce the male gametophyte pollen grains.

The male cones first produce spores by meiosis, which develop into pollen grains and rest on the edges of the cone. These are carried by the wind, and some will reach the female cones in pollination.. The pollen grains then directly enter the diploid sporangium in the ovule, and a female spore is produced by meiotic division inside the sporangium; this spore becomes the female gametophyte.

In several months, this will produce eggs, as the male spores produce sperm. A small tube grows from the male spore to the egg and releases the sperm, which fertilize the egg. After fertilization, which usually occurs over a year after pollination, the diploid zygote develops into an embryo, and the ovule grows a tough seed coat and becomes a seed. This will fall to the ground and germinate, eventually growing into another tree.

This method of reproduction enabled the conifers to dominate the earth during the Mesozoic Era. In the Cretaceous Period, however, a new line of plants emerged: the angiosperms. These have flowers onto which the pollen lands during pollination, after fertilization, the ovule grows into a fruit. These came to dominate temperate climates; however, conifers still dominate the northern climates of the world.

Procedures:
1. Diagram.
2. Define gymnosperm.
3. Diagram the life cycle of a "pine".
4. Describe conifers.