conifers

=Evolution of Conifers=
 * Conifers first appeared in history in the late Paleozoic period more than 300 million years ago.
 * They made up the majority of vegetation in the Mesozoic period
 * Conifers and their relatives are considered living fossils for they are some of the oldest plants. Conifers relatives include other gymnosperms such as gnetophyta, cycadophyta, and ginkgophyta.
 * When conifers adapted to dry and cool conditions, they developed new features like long thin leaves.
 * The adaptations greatly changed their appearance and structure. The shapes of the trees are shaped to help reduce the surface area from which water can be lost. Water is lost through evaporation.
 * They also developed different leaves. Their leaves got a thick, waxy layer to also conserve water. The needles are long and thin so it can catch more water.
 * All these adaptations not only changed conifers' appearance, but their limitations as well. Because of all these developments the trees can withstand many harsh conditions.

=Conifers in general=
 * Conifers are a part of the family of gymnosperms. Gymnosperms is derived from the Greek word gymnospermos. Gymnos= naked; sperma= seed.
 * Gymnosperms are divided into four divisions:
 * 1) //Cycadophyta >are mainly found in subtropical and tropical regions//
 * 2) //Gingkophyta >has only one genera left (maidenhair)//
 * 3) //Gnetophyta >has three genera//
 * 4) //Coniferophyta >the largest group//
 * Coniferophyta broken down is: coni, konos=cone; fer= bear, carry; phyta= plant
 * Conifers are vascular plants and all, but two are evergreen. The two exceptions are larches and bald cypresses. To be evergreen means to be green all year which is the same as saying that they do not lose their leaves every fall.
 * Their needles stay on for 2 to 14 years with the oldest ones being on the bottom and in the innermost parts of the tree.
 * There are more than 500 known species

=**Locations**=
 * Conifers can be found on every continent, but Antartica.
 * California is actually home to the oldest.
 * They can be found in forests and even on the southern tip of South America and islands like New Caledonia.
 * Some times coniferous forests are confused as temperate rainforests.
 * There are 200 species in North America alone.

=Types =
 * The most common types are pine, spruces, and firs.
 * They include the tallest, and the most massive trees on this planet. The tallest being Giant Redwoods and the widest being Sequoias.
 * Pine trees: Contains more than 100 species wordwide. Four types of leaves that pines can have are: seed leaves, juvenile leaves, scale leaves, and needle leaves. They are the most common type of conifers. They can live up to 1000 years.
 * Fir trees: Can grow up to 12 inches per year. Can live more than 200 years and have soft woods used for making plywood.
 * Cypress tres: Are the most distributed of conifer trees. Most stay as shrubs and don't grow to be trees. Their leaves change from scale-like to needle-like as they mature.
 * Spruce tree: Are famous for it growing rate which is 12 inches per year. The branches grow in a whorled shape.
 * Cedar tree: Usually found in mountainous areas and high altitudes. Can grow up to heights of 30-40 meters. Its wood makes valuable timber.[[image:examples-conifers.jpg width="541" height="321" align="left" caption="examples of some conifers"]]

=Reproduction=
 * Conifers are gymnosperms so they produce cones. The cones can be male or female.
 * Pollination is the transfer of the whole gametophyte to the female plant.
 * Conifers have their pollen spread by the wind.
 * Once the pollen grain is in between the stem of the female cone and an ovule the it is conisdered pollination.
 * The pollen cones (male) contain microsporocytes that undergo meiosis to produce haploid grains which have two air sacs that act like wings.
 * Ovulate cones (female) have megasporophylls that produce ovules that contain a single megasporium with a single megaspore cell. The pollen enters through an opening called micropyle.



=Uses=
 * Conifers make up the majority of lumber
 * Conifers are used for their wood that is used for pulp for paper
 * They are frequently used for landscaping because they are aesthically valuable (they are pretty)
 * They are used for religious purposes ( Ex. Christmas trees)
 * Some of them have edible seeds called pine nuts

=Videos= [|identifying certain types of conifers]videos can be found on the right side of the page in the link.

=Pictures and diagrams on structures of conifers=