Monday, March 13, 2006

Conifers success in the Northern Hemisphere

Conifers are the most successful of the gymnosperms; this group of
plants has seeds that are not enclosed in an ovary. They originally
emerged during the Carboniferous period, about 300 million years ago and
they are still around today. There are around 570 species and they cover
large areas of the temperate and sub Polar Regions. Their reproductive
structures are well protected, by the cones, hence the name conifers.
The other characteristics are: needle-like foliage but does not occur
with all conifers. The conifer group includes monkey puzzle trees of
South America and Australasia; the redwoods of China and the USA; and
the Pinaceae, the most successful conifer family which includes around
300 species of pines, larches, spruces, firs and cedars. The members of
this group have narrow, needle-like leaves that are suited to resist
drought, fire and frost. They have dominated the colder parts of the
northern temperate zones very successfully. This family has probably
benefited from the recent cooling and drying of the world's climate; it
has assisted them to spread further over the northern hemisphere. Boreal
forests of pine, spruce and larch cover huge areas of the sub arctic,
while evergreen forests of pines and cedars cover much of the drier
temperate areas, including the Mediterranean. The larches are one of the
few deciduous conifers and inhabit even the inhospitable plains of
northeast Siberia where not even tough conifer needles could survive the
cold dry winters.


Environmental and Water Sciences


  • This is WORD FOR WORD Plagiarism of the reference you provided. Please see the following posting


    You must write in your own words or put into quotes if it is other people's words or say the following is quoted from.

    In this exercise you passed off another person's work as your own and this is dishonest!

    By Anonymous Rich, at Friday, March 17, 2006 10:14:00 pm  

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