Plant Glo Essay, Research Paper
A brief review on the way terrestrial animal and plantCommunities are distributed globally IntroductionThis essay will look at the way terrestrial animal and plant communities are distributed globally. This can be achieved easily by looking at animal and plant communities within each terrestrial biome.The oxford 1995 dictionary defines terrestrial as ‘of the earth’ and ‘of or living on land’.I have decided to briefly review biomes, and the animals and plants within them because I feel that by understanding their concept we can see how it is possible for animals and plants that require different environments to survive, are be distributed globally.’A single biome can be widely scattered about the planet. Abiotic factors, such as climate are important in determining where a particular biome is located. There are longtitudal patterns of climate over the earth’s surface, and therefore, there are also longtitudal patterns of biome distribution over the earth’s surface’ (redbaron) Biomes can be defined as “The worlds major communities classified according to the pre-dominant vegetation and characterized by adaptations of organisms to that particular environment” (Campbell 1996).Biomes are large complexes of communities. The distribution of biomes on earth is influenced by annual patterns of rainfall and temperature. Fig. 1 clearly shows that it is possible for a country to be positioned on several terrestrial biomes because of where it is situated on the globe. Fig. 1 (Purves 1998) Hot deserts (subtype BW) are a type of terrestrial biome that can be found centered at 30| north and 30| south latitudes, respectively e.g. in North Africa, Mexico and the center of Australia. They cover approximately 1/5 of the earth’s surface. These deserts usually occur at low altitudes. They receive most of their rainfall in summer, which is less than 50cm a year, and can also receive winter rains from storms that form over the mid-latitude oceans. They have a considerable amount of specialized vegetation. Pollination and dispersal of fruits/seeds by animals are typical. There are few large mammals in the deserts because many are not capable of storing water and withstanding the heat and because they are too large to hide under objects or underground in order to stay out of the sun. Reptiles live here as well as small mammal’s e.g. kangaroo mice. Dominant animals are borrowers, and Kangaroo rats. Animals of this desert; insects, reptiles and birds survive by staying inactive, in protected hideaways during sun-up, and coming out at dusk or night, when the desert is cooler.Dominant plants are shrubs and short woody trees here; other plants include cacti, yuccas, prickly pears and brittlebush.The environment here makes it difficult for people to colonize in large numbers. Tropical rain forest have year round high temperature, usually two rainy seasons per year near the equator, as the sun passes over each equinox but only one at higher latitudes. Daily temperature range exceeding the seasonal range. There are one or more relatively dry months (with less than 100mm rainfall)Tree growth is luxuriant with emergent trees to 60m and canopy trees to 30m most plant species are evergreen their leaves elliptic. Tree trunks are usually light-coloured, straight and vertical many with flaring buttresses. Lianan (large woody vines) are prominent. Epiphylls (growing on the leaves of other plants) are found only here. Decomposed plant material recycles almost instantly so there is very little leaf litter. Many plants are rare. There is a large variety of insects many species are rare. Large mammals are not diverse as locomotion is hindered by dense vegetation. Tree shrews, squirrels, sloth, forest deer, antelope, cats live here. Birds reach their greatest diversity here pigeons, parrots, hummingbirds & toucans.Lizards, snakes and frogs and caecilians are a major amphibian group restricted to the tropics, mostly in forested areas.
Camouflage is defense for smaller animals e.g. python, chameleons Grasslands are temperate environments with warm & wet/hot summers and cool/very cold & dry winters. Winds play an important role here.Largely dominated by grasses, average height of grass is correlated with rainfall so there are tall/medium/short grass prairie zones across longitudinal gradient.There are a fair amount of mammals but usually no more than 2-3 species of large grazing mammals occur in typical temperate grassland compared to 12 + in some tropical (savanna) grasslands. Major vertebrate characteristic of grasslands are passerine birds (larks), pipits and buntingsGrass family is one of the largest in the world and grasses, as individual plants are probably the most abundant plants in the world. Grass is relatively resistant to fire and grazing because leaves grow from the base (unlike most plants) so long as the base remains intact, new growth will follow. Grass is wind pollinated, very effective in this open environment. Perennial grasses and many forbs have showy flowers. Grasses are often very colourful when forbs are in bloom. Tundra biome (subtype ET) ‘is found in the Arctic and high in mountains at all latitudes’ (purves 1998) They have cool summers very cold winters areas of low rainfall that should be desert-like are moist because evapotranspiration is low (low temperature) and permafrost holds water. At high altitudes, temperature is never high and can drop below freezing on clear nights.Winds are often severe. Vegetation is lacking at the north extreme due to climatic extremity. Low areas can be very wet; ridges very dry at the same time because of combination of low rainfall and persistent surface water, so there is substantial variation in plant communities here. Most plants grow flat on the ground, some so densely packed they can be known as “cushion plants” in this windy habitat, the majority of seeds are wind-dispersed. Some plants only grow around areas of heavy animal use where nitrogenous wastes serve in lieu of soil nutrients; plants here are perennial herbs and small shrubs. Birds are primarily those with long wings and rapid flight (waterfowl, jaegers and shorebirds) which are able to make long migrations. They effectively utilize high productivity in summer and escape its winter harshness. Most tundra animals go elsewhere for winter, or are dormant for most of the year. Insects protect themselves from winter under water; many utilize glycerol in their body tissues as antifreeze. Supported historically very low human population densities. Further examples of terrestrial biomes are:C PolarC Coniferous ForestC Deciduous ForestC Tropical Rain Forest ConclusionBioclimatic zones (biomes) are appropriate divisions to organize the natural world, animals and plants, which live in each of them posses similar abilities of adaptation to them, in particular to the climates of these zones.The climate is perhaps the most important element in determining what animals and plants live in an area. Each spot in the world has its own climate. Vegetation of an area is dependent on climate and soils, which in turn influence both animal and plant species that can exist in an area. Bibliography Gould J.L & Keeton W.Ts, 1996 Biological Science w.w.norton & company:New York.Purves/Orians/Heller/Sadava, 1998 Life, the science of biology sinaver associates inc:USA.www.ucmp.berkeley.edu/glossery/gloss/biome/desert/www.alaska.net/zimco/bbiome.htmwww.tesarta.com/www/resources/library/biomes.htmwww.ups.edu/biology/museum/worldbiomes.htmlhttp://redbaron.bishops.ntc.nf.ca/wells/biomes/html/terrestrial.htmwww.panda:org/research/yr2000/biomes/htmhttp://mason.gmv.edu/wjsettle/ecosys.htm//members.aol.com/the buddha6/biomes/importan.htmlwww.cnie.org/nle/biodv.6.html#BIOMES:DEFINITION AND EXAMPLES References Campbell 1996