Essay Title: 

BIOLOGY

March 27, 2016 | Author: | Posted in ecology, nature

ECOLOGY : DIFFERENT BIOMES IN THE EARTH

Ecology is the branch of science that discusses the study of interaction between organism and their environment . It has so many aspects , and one of these is all about the biomes of the earth

A biome is a large geographical area that contains a particular group of plants and animals and has a specific physical environment resulting from interaction among climate , biota and substrate of region . An important characteristic of a biome ‘s physical environment is the consistency of each of its factors . For example , through [banner_entry_middle]

a biome there will be the same basic temperature , land shape , and soil , as well as the same basic amounts of sunlight and rainfall . Because of the consistency of the environmental factors , the same types of organisms usually exist throughout the biome . Campbell , et al (2000 ) cited that many biomes are named for their predominant vegetation . These biomes are classified into two : the terrestrial biomes (those on land ) and the aquatic biomes (those on water . However , terrestrial biomes are more dominant than aquatic biomes

Terrestrial biomes spread all over large areas of the earth and ecologists have divided the earth into terrestrial biomes based upon climax vegetation . Climax vegetation is the community of plants that grow in an area at the end of the succession . Although other environmental factors must be considered , a terrestrial biome is usually determined by the interaction of two factors : the amount of rain and prevailing temperatures . The different types of terrestrial biomes are the following

The Tundra biomes are found in the far-northern parts of North America Europe , and Asia . There are two main types of tundra : arctic tundra and alpine tundra . The arctic tundra is found in the extreme north . The alpine tundra is found near the tops of high mountains

In this biome , the temperature is extremely low . Pinkston , Jr . and Anderson (1999 , mentioned that although the tundra remains frozen during most of the year , for about two months the first meter (3 ft ) of ground thaws out . Below this surface layer is a layer that never thaws called the permafrost . Because water cannot penetrate the permafrost the melting snow forms many bogs , lakes , and streams during the short warm season . Few small trees , mossy ground , lichens and grasses make up most of the climax vegetation of the tundra

During the warm season many insects live in the tundra . Most of these insects lay eggs that are resistant to the freezing winter temperatures Then when the ground thaws the following year , the eggs hatch . Also during the warm season , many birds migrate to the tundra and build nests . The tundra provides a good environment for the birds , since there are few predators and the abundance of insects makes it easy for them to obtain food . Most birds leave the tundra before the snow returns

Coniferous forests are biomes in which the principal trees are cone-bearers , such as spruce , pine , fir , and hemlock , although there are also longleaf pines , all one species . Fire is essential to the longleaf coniferous forest and to many others . Without periodic burning deciduous trees will frequently replace the conifers

By far the most extensive coniferous forest is the taiga , the northern (boreal ) coniferous forest (Campbell , 2000

Deciduous Forests are found south of taiga , there are more variable than taiga and tundra . These are dominated by broad-leaved trees foliage changes color in autumn and then drops . There are more plant species in deciduous forests than tundra and taiga , usually fruit bearings ones Squirrels , deer , foxes and bears can be found here . According to Pinkston , Jr (1994 ) these areas have growing seasons longer than six months , a yearly rainfall of about 100 cm (40 in ) of rain , and summers without long droughts

Most tropical rain forests are near the equator and their temperatures are quite warm . Rain forests often have a greater difference between the nighttime and the daytime temperatures than between the seasonal temperatures . The annual rainfall in a tropical rain forest is 200 to 225 cm . During rainy season the forest usually receives some rain every day . However , during the dry season rain may fall only once a week or in some areas , only once a month

There are three basic layers of plant growth in most tropical rain forests . The emergent , made up of the tall trees that grow above the rest the canopy , made up of trees up to 24 to 30m and the last is the understory , includes plants that grow on forest floor (Pinkston , Jr 1999

Savannas are simple in structure compared to tropical rain forests Frequent fires , caused by lightning or human activity , and grazing animals inhibit further invasion by tress . Fires and grazers also maintain the small-growth form of grasses and nonwoody , broadleaf dicot plant that grow with them . These grasses grow rapidly providing food form many species of animals

The savanna is the home of many of the world ‘s herbivores and their predators , as well us burrowing animals including anthropods . In Africa there are giraffes , zebras , antelopes , baboons , lions , and cheetahs . In Australia , kangaroos of different species can be seen hoping all over savannas and in North America , animals such as bison , deer , black bear and coyotes can be found (Campbell , 2000

Deserts are arid land area and due to evaporation , more water is lost than gained through precipitation . There are different types of deserts in addition to the familiar hot , dry desert of rock and sand that is almost barren of plants . There is the semiarid deserts of scattered trees , scrub and grasses coastal deserts , like the Atacama of Chile and the deserts on the polar ice cap of the Antarctic and Greenland (Grolier , 2000 vol .6

Oases are pockets of fertile land in a dry desert . These occur where an aquifer , or underground stream , comes to the surface

These deserts can spread . This may happen because the climate becomes drier or nearby land is overgrazed by farm animals (Grollier ‘s 2002

Grasslands , a major world Biome of Earth , are characterized by the dominance of grasses , the smooth cover they provide , and the monotony of flat to rolling terrain . Trees ands shrubs occur as scattered individuals or are concentrated along streams or in low areas . Resident wildlife must be adapted to distinct wet and dry seasons , temperature extremes , drying winds , and prolonged droughts (Grolier ,2000 vol . 8

Chaparral , a Spanish word , which translated means place of evergreen shrub oaks , is a region of dense , spiny shrubs with tough , evergreen leaves . It is characterized as being very hot and dry . Its climate mainly results from the cool ocean currents which usually results in mild , rainy winters and long , dry summers (Campbell , 2000 . As for the temperature , the winter is very mild and is usually about 10o C . Then there is summer . It is so hot and so dry that at 40oC droughts are very common and periodic fires , usually caused by lightings , occur . However the vegetation of this biome is adapted to such condition and infact these plants need the occasional fires for long-term maintenance

Animals also have adapted to this sparse and rough terrain by becoming agile climbers , foraging over larger areas , and varying their diet to include the often scrubby brush lands . Many chaparral animals are nocturnal . They burrow underground to escape the heat in the day and come out at night to feed . This allows them to conserve water (which is scarce , energy and also keeps the animal safe during fires . Other chaparral animals , like some mice and lizards , secrete semi-solid urine in to reduce water loss

Having seen the different terrestrial biomes , we will now discuss the aquatic biomes

There are two major types of aquatic biomes : freshwater biomes and marine biomes

Aquatic biomes are further divided by depth , current , and temperature (Pinkston ,Jr , 1994

Freshwater biomes are separated by ecologists in two main categories – those have standing water (lakes , ponds , swamps , and bogs ) and those that have running water the streams and rivers . One can see that organisms that exist in standing-water biomes do not exist in the running-water , this just show the big difference of the two . Although there are four other factors that further separate standing-water and running-water . The following are concentration of dissolved oxygen and carbon dioxide , temperature , transparency , and concentration of minerals that determine which organisms that live in each particular biome

Life in a freshwater biome is categorized as benthos organisms , those or rest to the bottom of a pond or lake , examples are the worms , snails and clams nekton organisms , fish , newts , large swimming insects , and some turtles , that they are able to swim and navigate at will plankton organisms , more or less found floating with the current these include protozoans , larva stages of several insects , tiny algae and other organisms and transient animals , those animals that spend only a part of their time in the aquatic biome but are in some ways dependent upon it (Pinkston , Jr . 1994

Marine biomes cover around 70 percent of the earth ‘s surface . It can be observed that different areas of the ocean have their own biotic communities and physical environments . During high tide the intertidal zone is covered with water , while in low tide is exposed to the air The alternating environment suits the characteristics of the organisms in this intertidal zone

Surrounding each continent is a continental shelf , and along these shelves the ocean is only about 1 ,000 m deep . Abundance of organisms can be observed along the continental shelves . Usually commercial fishing and other marine products is done along continental shelves

Penetration of light is only a short distance into ocean water Photosynthetic planktons serve as the energy source of the other organisms in the continental shelf (Pinkston and Anderson , 1999

Different kinds of biomes were discussed above , and mentioning the existence of different species in each biome showed their richness and abundance . However it was also shown that biomes have the tendency to grade into each other , and within each biome there is some sort of local differences or variation , a patchy , rather than a uniform , appearance To illustrate this , let us look in the northern coniferous forests snowfall may break branches and small trees , allowing openings where deciduous trees such as aspen and birch can grow . Local storms and fires also causing openings in many biomes (Campbell , 2000

The richness of biomes in the planet earth is undeniable , but somehow these natural biomes are destroyed and interrupted by human activity thus resulting to the high rate of biome alteration . Because of this a recommendation is given that henceforth , individuals , different institutions and various organizations should support the movement of the conservation biology not only in the preservation , but much more in sustaining of ecosystem and landscapes , considering the inevitability of the extinct and the endangered species

It is further recommended that further studies must be conducted for this purpose

BIBLIOGRAPHY

Campbell , N . A , Mitchell , L . G . and Reece , J . B . Terrestrial Ecosystems . Biology : Concepts

and Connections . International Ed .USA : Addison Wesley Longman , Inc 2000

Grolier . Deserts . Grolier Encyclopedia of Knowledge . International Edition .2000 .USA :Grolier

Incorporated .Vol . 6

Grolier . Grasslands . Grolier Encyclopedia of Knowledge International Edition .2000

USA :Grolier Incorporated .Vol . 8

Pinkston , Jr . Major Biomes of the World . Life Science for Christian Schools . USA :Bob Jones

University Press . 1994

Pinkston W . Jr , and Anderson , D .R . Major Biomes of the World . Life Science for Christian

Schools . 2nd Edition . USA :Bob Jones University Press . 1999

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