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    Tropical Rain Forest

    ByMUJAHIDAH

    071404184

    ICP 07

    BIOLOGY DEPARTEMENT

    SCIENCE AND MATHEMATIC FACULTY

    MAKASSAR STATE UNIVERSITY

    2010

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    CHAPTER I

    INTRODUCTION

    A. BackgroundRainforests are forests characterized by high rainfall, with definitions

    setting minimum normal annual rainfall between 17502000 mm (68-

    78 inches). The monsoon trough, alternately known as the intertropical

    convergence zone, plays a significant role in creating Earth's tropical rain

    forests. 40 to 75% of all species on the world's habitats are indigenous to the

    rainforests. It has been estimated that many millions of species of plants,

    insects, and microorganisms are still undiscovered. Tropical rainforests have

    been called the "jewels of the Earth", and the "world's largest pharmacy",

    because over one quarter of natural medicines have been discovered there.

    Rainforests are also responsible for 28% of the world's oxygen turn over, often

    misunderstood as oxygen production, processing it through photosynthesis

    from carbon dioxide and storing it as carbon through biosequestration.

    The undergrowth in a rainforest is restricted in many areas by the lack

    of sunlight at ground level. This makes it possible to walk through the forest.

    If the leaf canopy is destroyed or thinned, the ground beneath is sooncolonized by a dense, tangled growth of vines, shrubs, and small trees called a

    jungle. There are two types of rainforest, tropical rainforest and temperate

    rainforest.

    Many of the world's rainforests are associated with the location of the

    monsoon trough, also known as the intertropical convergence zone. Tropical

    rainforests are rainforests in the tropics, found near the Equator (between the

    Tropic of Cancer and Tropic of Capricorn) and present in Southeast Asia

    (Myanmar to Philippines, Indonesia, Papua New Guinea, and northeasternAustralia), Sri Lanka, Sub-Saharan Africa from Cameroon to the Congo

    (Congo Rainforest), South America (e.g. the Amazon Rainforest), Central

    America (e.g. Bosaws, southern Yucatn Peninsula-El Peten-Belize-

    Calakmul), and on many of the Pacific Islands (such as Hawai i). Tropical

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    rainforests have been called the "Earth's lungs," although it is now known that

    rainforests contribute little net oxygen additions to the atmosphere through

    photosynthesis.

    B. PurposeThe purpose of this report are:

    1. To know what are tropical rainforests?2. To know where are rainforests located?3. To know what makes a rainforest?4. To knowstructure and character5. To knowwhy do rainforests have so many kinds of plants and animals?

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    many seasonally flooded forests, which are annually replenished with fertile

    silt.

    Tropical rain forests have been subjected to heavy logging and

    agricultural clearance throughout the 20th century, and the area covered by

    rainforests around the world is rapidly shrinking.

    Rainforests are also often called the "Earth's lungs," however there is

    no scientific basis for such a claim as tropical rainforests are known to be

    essentially oxygen neutral, with little or no net oxygen production.

    Tall, broad-leaved evergreen trees are the dominant plants, forming a

    leafy canopy over the forest floor. Taller trees, called emergents, may rise

    above the canopy. The upper portion of the canopy often supports a rich flora

    of epiphytes, including orchids, bromeliads, mosses, and lichens, who live

    attached to the branches of trees. The undergrowth or understory in a rain

    forest is often restricted by the lack of sunlight at ground level, and generally

    consists of shade-tolerant shrubs, herbs, ferns, small trees, and large woody

    vines which climb into the trees to capture sunlight. The relatively sparse

    under story vegetation makes it possible for people and other animals to walk

    through the forest. In deciduous and semi-deciduous forests, or forests where

    the canopy is disturbed for some reason, the ground beneath is soon colonized

    by a dense tangled growth of vines, shrubs and small trees called jungle.

    The temperature ranges from 15 (59F) to 50C (122F) and 125 to

    660 cm of rainfall yearly

    C.LayersThe rainforest is divided into five different layers, each with different

    plants and animals, adapted for life in the particular area. These are: the

    ground layer, the shrub layer, the under storey layer, the canopy layer and the

    emergent layer. Only the emergent layer is unique to tropical rainforests, while

    the others are also found in temperate rainforests.

    The emergent layer contains a small number of very large trees which

    grow above the canopy layer, reaching heights of 45-55 m, although on

    occasion a few species will grow up to 70 m or 80 m tall. They need to be able

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    to withstand the hot temperatures and strong winds. Eagles, butterflies, bats

    and certain monkeys inhabit this layer.

    The canopy is the primary layer of the forest and forms a roof over

    the two remaining layers. Most canopy trees have smooth, oval leaves that

    come to a point. It's a maze of leaves and branches. Many animals live in this

    area since food is abundant. Those animals include: snakes, toucans and tree

    frogs.

    Little sunshine reaches the understory layer, so the plants have to

    grow larger leaves to obtain sufficient sunlight. The plants in this area seldom

    grow to 12 feet. Many animals live here including jaguars, red-eyed tree frogs

    and leopards. There is a large concentration of insects here.

    The shrub layer and forest floor are very dark. Few plants grow in this

    area, as a result. Since hardly any sun reaches the forest floor things begin to

    decay quickly. A leaf that might take one year to decompose in a regular

    climate will disappear in 6 weeks. Giant Anteaters live in this layer.

    D. Humanuses1. Habitation

    Tropical rainforests are unable to support human life. Food

    resources within the forest are extremely dispersed due to the high

    biological diversity and what food does exist is largely restricted to the

    canopy and requires considerable energy to obtain. Some groups of hunter-

    gatherers have exploited rainforest on a seasonal basis but dwelt primarily

    in adjacent savanna and open forest environments where food is much

    more abundant. Other peoples described as rainforest dwellers are hunter-

    gatherers who subsist in large part by trading high value forest products

    such as hides, feathers, and honey with agricultural people living outside

    the forest.

    2. Conversion to agricultural landWith the invention of agriculture, humans were able to clear

    sections of rainforest to produce crops, converting it to open farmland.

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    Such people, however, obtain their food primarily from farm plots cleared

    from the forest and hunt and forage within the forest to supplement this.

    Agriculture on formerly forested land is not without difficulties.

    Rainforest soils are often thin and leached of many minerals, and the

    heavy rainfall can quickly leach nutrients from area cleared for cultivation.

    People such as the Yanomamo of the Amazon, utilise slash-and-burn

    agriculture to overcome these limitations and enable them to push deep

    into what were previously rainforest environments. However, these are not

    rainforest dwellers, rather they are dwellers in cleared farmland that make

    forays into the rainforest. Up to 90% of the typical Yanamomo diet comes

    from farmed plants.

    3. Cultivated foods and spicesCoffee, chocolate, banana, mango, papaya, macadamia, avocado,

    and sugarcane all originally came from tropical rainforest and are still

    mostly grown on plantations in regions that were formerly primary forest.

    In the mid-1980s and 90s, 40 million tons of bananas were consumed

    worldwide each year, along with 13 million tons of mangos. Central

    American coffee exports were worth US$3 billion in 1970. Much of the

    genetic variation used in evading the damage caused by new pests is still

    derived from resistant wild stock. Tropical forests have supplied 250

    cultivated kinds of fruit, compared to only 20 for temperate forests.

    Forests in New Guinea alone contain 251 tree species with edible fruits, of

    which only 43 had been established as cultivated crops by 1985.

    4. Pharmaceutical and biodiversity resourceTropical rainforests are called "the world's largest pharmacy

    because of the large amount of natural medicines discovered in rainforests

    that are derived from rainforest plants. For example, rain forests contain

    the "basic ingredients of hormonal contraception methods, cocaine,

    stimulants, and tranquilizing drugs" (Banks 36). Curare (a paralyzing

    drug) and quinine (a malaria cure) are also found there.

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    5. Positive ImpactsOnset dates and prevailing wind currents of the southwest summer

    monsoon. Despite the negative effects of tourism in the tropical

    rainforests, there are also several important positive effects.

    y An increase in tourism has increased economic support, allowing morerevenue to go into the protection of the habitat. Tourism can contribute

    directly to the conservation of sensitive areas and habitat. Revenue

    from park-entrance fees and similar sources can be utilised specifically

    to pay for the protection and management of environmentally sensitive

    areas. Revenue from taxation and tourism provides an additional

    incentive for governments to contribute revenue to the protection of

    the forest.

    y Tourism also has the potential to increase public appreciation of theenvironment and to spread awareness of environmental problems when

    it brings people into closer contact with the environment. Such

    increased awareness can induce more environmentally conscious

    behavior. Tourism has had a positive effect on wildlife preservation

    and protection efforts, notably in Africa but also in South America,

    Asia, Australia, and the South Pacific.

    6. Ecosystem servicesIn addition to extractive human uses rain forests also have non-

    extractive uses that are frequently summarized as ecosystem services. Rain

    forests play an important role in maintaining biological diversity,

    modulating precipitation, infiltration and flooding and by increasing

    scientific knowledge.

    E.Flora and faunaMore than half of the world's species of plants

    and animals are found in the rainforest. Rainforests

    support a very broad array of fauna including

    mammals, reptiles, birds, and invertebrates. Mammals

    may include primates, felids, and other families. Reptiles include snakes,

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    turtles, chameleons, and other families while birds include such families as

    vangidae and Cuculidae. Dozens of families of invertebrates are found in

    rainforests. Fungi are also very common in rainforest areas as they can feed on

    the decomposing remains of plant and animal life. These species are rapidly

    disappearing due to deforestation, habitat loss, and biochemical releases into

    the atmosphere.

    1. Plant LifeBesides these four layers, a shrub/sapling layer receives about 3 %

    of the light that filters in through the canopies. These stunted trees are

    capable of a sudden growth surge when a gap in the canopy opens above

    them.

    The air beneath the lower canopy is almost always humid. The

    trees themselves give off water through the pores (stomata) of their leaves.

    This process, called transpiration, can account for as much as half of the

    precipitation in the rain forest.

    Rainforest plants have made many adaptations to their

    environment. With over 80 inches of rain per year, plants have made

    adaptations that helps them shed water off their leaves quickly so the

    branches don't get weighed down and break. Many plants have drip tips

    and grooved leaves, and some leaves have oily coatings to shed water. To

    absorb as much sunlight as possible on the dark understory, leaves are

    very large. Some trees have leaf stalks that turn with the movement of the

    sun so they always absorb the maximum amount of light. Leaves in the

    upper canopy are dark green, small and leathery to reduce water loss in the

    strong sunlight. Some trees will grow large leaves at the lower canopy

    level and small leaves in the upper canopy. Other plants grow in the upper

    canopy on larger trees to get sunlight. These are the epiphytes such as

    orchids and bromeliads. Many trees have buttress and stilt roots for extra

    support in the shallow, wet soil of the rainforests.

    Over 2,500 species of vines grow in the rainforest. Lianas start off

    as small shrubs that grow on the forest floor. To reach the sunlight in the

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    upper canopy it sends out tendrils to grab sapling trees. The liana and the

    tree grow towards the canopy together. The vines grow from one tree to

    another and make up 40% of the canopy leaves. The rattan vine has spikes

    on the underside of its leaves that point backwards to grab onto sapling

    trees. Other "strangler" vines will use trees as support and grow thicker

    and thicker as they reach the canopy, strangling its host tree. They look

    like trees whose centers have been hollowed out.

    Dominant species do not exist in tropical rainforests. Lowland

    dipterocarp forest can consist of many different species of

    Dipterocarpaceae, but not all of the same species. Trees of the same

    species are very seldom found growing close together. This bio diversity

    and separation of the species prevents mass contamination and die-off

    from disease or insect infestation. Bio diversity also insures that there will

    be enough pollinators to take care of each species' needs. Animals depend

    on the staggered blooming and fruiting of rainforest plants to supply them

    with a year-round source of food.

    2. Animal LifeMany species of animal life can be found in the rain forest.

    Common characteristics found among mammals and birds (and reptiles

    and amphibians, too) include adaptations to a life in the trees, such as the

    prehensile tails of New World monkeys. Other characteristics are bright

    colors and sharp patterns, loud vocalizations, and diets heavy on fruits.

    Insects make up the largest single group of animals that live in

    tropical forests. They include brightly colored butterflies, mosquitoes,

    camouflaged stick insects, and huge colonies of ants.

    The Amazon river basin rainforest contains a wider variety of plant

    and animal life than any other biome in the world. The second largest

    population of plant and animal life can be found in scattered locations and

    islands of Southeast Asia. The lowest variety can be found in Africa.

    There may be 40 to 100 different species in 2.5 acres ( 1 hectare) of a

    tropical rain forest.

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    When early explorers first discovered the rainforests of Africa,

    Southeast Asia and South America, they They were amazed by the dense

    growth, trees with giant buttresses, vines and epiphytes . The tropical

    vegetation grew so dense that it was difficult to cut one's way through it. It

    was thought at the time that the soil of a rainforest must be very fertile,

    filled with nutrients, enabling it to support the immense trees and other

    vegetation they found.

    A study in the Amazon rainforest found that 99% of nutrients are

    held in root mats. When a rainforest is burned or cut down the nutrients are

    removed from the ecosystem. The soil can only be used for a very short

    time before it becomes completely depleted of all nutrients.

    F. SoilsDespite the growth of vegetation in a tropical rainforest, soil quality is

    often quite poor. Rapid bacterial decay prevents the accumulation of humus.

    The concentration of iron and aluminium oxides by the laterization process

    gives the oxisols a bright red color and sometimes produces minable deposits

    such as bauxite. Most trees have roots near the surface as there are not many

    nutrients below the ground; most of the trees minerals come from the top layer

    of decomposing leaves (mainly) and animals. On younger substrates,

    especially of volcanic origin, tropical soils may be quite fertile. If the trees are

    cleared, the rain can get at the exposed soil, washing it away. Eventually

    streams will form, then rivers. Flooding becomes possible.

    Today we know that the soil of the tropical rainforests is shallow, very

    poor in nutrients and almost without soluble minerals. Thousands of years of

    heavy rains have washed away the nutrients in the soil obtained from

    weathered rocks. The rainforest has a very short nutrient cycle. Nutrients

    generally stay in an ecosystem by being recycled and in a rainforest are mainly

    found in the living plants and the layers of decomposing leaf litter. Various

    species of decomposers like insects, bacteria, and fungi make quick work of

    turning dead plant and animal matter into nutrients. Plants take up these

    nutrients the moment they are released.

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    G.Effect on global climateA natural rainforest emits and absorbs vast quantities of carbon

    dioxide. On a global scale, long-term fluxes are approximately in balance, so

    that an undisturbed rainforest would have a small net impact on atmospheric

    carbon dioxide levels, though they may have other climatic effects (on cloud

    formation, for example, by recycling water vapor). No rainforest today can be

    considered to be undisturbed. Human induced deforestation plays a significant

    role in causing rainforests to release carbon dioxide, as do natural processes

    such as drought that result in tree death. Some climate models run with

    interactive vegetation and predict a large loss of Amazonian rainforest around

    2050 due to drought, leading to forest dieback and the subsequent feedback of

    releasing more carbon dioxide.

    H.DeforestationTropical and temperate rainforests have

    been subjected to heavy logging and agricultural

    clearance throughout the 20th century and the

    area covered by rainforests around the world is shrinking. Biologists have

    estimated that large numbers of species are being driven to extinction (possibl

    y more than 50,000 a year; at that rate, says E. O. Wilson of Harvard

    University, a quarter or more of all species on Earth could be exterminated

    within 50 years) due to the removal of habitat with destruction of the

    rainforests.

    Another factor causing the loss of rainforest is expanding urban areas.

    Littoral rainforest growing along coastal areas of eastern Australia is now rare

    due to ribbon development to accommodate the demand for seachange

    lifestyles.

    The forests are being destroyed at a rapid pace. Almost 90% of West

    Africa's rainforest has been destroyed. Since the arrival of humans 2000 years

    ago, Madagascar has lost two thirds of its original rainforest. At present rates,

    tropical rainforests in Indonesia would be logged out in 10 years and Papua

    New Guinea in 13 to 16 years.

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    Several countries, notably Brazil, have declared their deforestation a

    national emergency. Amazon deforestation jumped by 69% in 2008 compared

    to 2007's twelve months, according to official government data. Deforestation

    could wipe out or severely damage nearly 60% of the Amazon Rainforest by

    2030, says a new report from WWF.

    However, a January 30, 2009 New York Times article stated, "By one

    estimate, for every acre of rain forest cut down each year, more than 50 acres

    of new forest are growing in the tropics..." The new forest includes secondary

    forest on former farmland and so-called degraded forest.

    From a new recent report in September 2009, new opportunities are

    beginning to discover they could save the rainforest. In Brazil, Environment

    Minister Carlos Minc announced proudly that the rate of deforestation of the

    Amazon fell by 46 percent last year. That means the lowest logging level since

    the country began to keep annual statistics 21 years ago. But not only Brazil

    has reduced deforestation as a whole also slowed the loss of forest down. The

    annual decline is now over two thousand. Deforestation decreases in a country

    as it becomes richer and more industrialized. Therefore, there are exceptions

    in a group of countries where deforestation has become so profitable that it is

    an important part in the growth of prosperity. New goal is to stop felling the

    forest, but also in managing the forest long-term, which occurs on a larger

    scale. More police officers guarding the rainforest, and stifle the illegal

    logging.

    I. Where Are The Rainforests1. Central America

    This region was once entirely covered with

    rainforest, but large areas have been cleared for

    cattle ranching and for sugar cane plantations.

    Like other major rainforests, the jungles and mangrove swamps of Central

    America contain many plants and animals found nowhere else. Central

    America is famous for its large number of tropical birds, including many

    kinds of parrots.

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    2. The AmazonThe Amazon jungle is the world's largest tropical

    rainforest. The forest covers the basin of the

    Amazon, the world's second longest river.

    The Amazon is home to the greatest variety of

    plants and animals on Earth. A 1/5 of all the world's plants and birds and

    about 1/10 of all mammal species are found there.

    3. AfricaCentral Africa holds the world's second largest

    rainforest. To the south east, the large island of

    Madagascar was once intensively forested, but now

    much of it is gone.

    Africa contains areas of high cloud forest, mangrove swamps and flooded

    forests. The island of Madagascar is home to many unique plants and

    animals not found anywhere else.

    4. Southern AsiaThe rainforests of Asia stretch from India and Burma

    in the west to Malaysia and the islands of Java and

    Borneo in the east. Bangladesh has the largest area of

    mangrove forests in the world.

    In Southeast Asia the climate is hot and humid all year

    round. In the mainland Asia it has a subtropical climate with torrential

    monsoon rains followed by a drier period.

    5. AustralasiaMillions of years ago, Australia, New Zealand and the

    island of New Guinea formed part of a great forested

    southern continent, isolated from the rest of the world.

    Today these countries contain many different species

    of animal that occur nowhere else.

    Undergrowth in Australia's tropical forests is dense and lush. The forests

    lie in the path of wet winds blowing in from the Pacific.

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    CHAPTER III

    DISCUSSION

    A. What are Rainforests?Tropical rainforests are forests with tall trees, warm climate, and lots

    of rain. In some rainforests it rains more than one inch every day.

    Tropical rain forests have been subjected to heavy logging and

    agricultural clearance throughout the 20th century, and the area covered by

    rainforests around the world is rapidly shrinking.

    B. Where are Rainforests Located?Rainforests are found in the tropics, the region between the Tropic of

    Capricorn and Tropic of Cancer. In this region the sun is very strong and

    shines about the same amount of time every day all year long making the

    climate warm and stable.

    Rainforests are found in Africa, Asia, Australia, and Central and

    South America. The largest rainforest in the world is the Amazon rainforest.

    C. What Makes a Rainforest?Each rainforest is unique but there are certain features common to all

    tropical rainforests.

    1. Location: rainforests lie in the "tropics"2. Rainfall: rainforests receive at least 80 inches (200 centimeters) of rain per

    year

    3. Canopy: rainforests have a canopy which is the layer of branches andleaves formed by closely spaced rainforest trees. Most of the plants and

    animals in the rainforest live in the canopy. The canopy may be 100 feet

    above the ground.

    4. Biodiversity: rainforests have a high level of biological diversity or biodiversity. Biodiversity is the name for all living things -- like plants,

    animals, and fungi -- found in an ecosystem. Scientists believe that about

    half of the plants and animals found on earth's land surface live in

    rainforests.

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    5. Symbiotic relationships between species: species in the rainforest oftenwork together. A symbiotic relationship is a relationship where two

    different species benefit by helping each other. For example some plants

    produce small housing structures and sugar for ants. In return the ants

    protect the plants from other insects that may want to feed on the plant's

    leaves

    D. What is The Canopy?In the rainforest most plant and animal life is not found on the forest

    floor but in the leafy world known as the canopy. The canopy, which may be

    over 100 feet above the ground, is made up of the overlapping branches and

    leaves of rainforest trees. Scientists estimate that 70-90% of life in the

    rainforest is found in the trees making this the richest habitat for plant and

    animal life. Many well-known animals including monkeys, frogs, lizards,

    birds, snakes, sloths, and small cats are found in the canopy.

    The environment of the canopy is very different from the

    environment of the forest floor. During the day, the canopy is drier and hotter

    than other parts of the forest and the plants and animals that live there are

    specially adapted for life in the trees. For example, because the amount of

    leaves in the canopy can make it difficult to see more than a few feet, many

    canopy animals rely on loud calls or lyrical songs for communication. Gaps

    between trees mean that some canopy animals fly, glide, or jump to move

    about in the treetops.

    Scientists have long been interested in studying the canopy but

    because of the height of rainforest trees research has been difficult until

    recently. Today there are special facilities with rope bridges, ladders, and

    towers to help scientists discover the secrets of the canopy.

    E. The Rainforest FloorThe leaves of the canopy makes the ground layer of the rainforest is

    often a dark and humid place. However, despite its constant shade, the

    rainforest floor is an important part of the forest ecosystem.

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    The forest floor is where decomposition takes place. Decomposition

    is the process by which decomposers like fungi and microorganisms break

    down dead plants and animals and recycle essential materials and nutrients.

    Many of the largest rainforest animals are found on the forest floor. Some of

    these include elephants, the tapir, and the jaguar.

    F. Structure And CharacterTropical rainforests across the world are quite diverse, but share several

    defining characteristics including climate, precipitation, canopy structure,

    complex symbiotic relationships, and diversity of species. Every rainforest

    does not necessarily conform to these characteristics and most tropical

    rainforests do not have clear boundaries, but may blend with adjoining

    mangrove forest, moist forest, montane forest, or tropical deciduous forest.

    1. GEOGRAPHY AND CLIMATETropical rainforests lie in the "tropics," between the Tropic of

    Capricorn and Tropic of Cancer. In this region sunlight strikes Earth at

    roughly a 90-degree angle resulting in intense solar energy (solar energy

    diminishes as you move farther north or south). This intensity is due to the

    consistent day length on the equator: 12 hours a day, 365 days per year

    (regions away from the equator have days of varying length). This

    consistent sunlight provides the essential energy necessary to power the

    forest via photosynthesis.

    Because of the ample solar energy,

    tropical rainforests are usually warm year

    round with temperatures from about 72-93F

    (22-34C), although forests at higher

    elevations, especially cloud forests, may be

    significantly cooler. The temperature may

    fluctuate during the year, but in some

    equatorial forests the average may vary as little as 0.5F (0.3C) throughout

    the year. Temperatures are generally moderated by cloud cover and high

    humidity.

    Map showing world

    distribution of rainforests

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    2. PRECIPITATIONAn important characteristic of rainforests is apparent in their name.

    Rainforests lie in the intertropical convergence zone where intense solar

    energy produces a convection zone of rising air that loses its moisture

    through frequent rainstorms. Rainforests are subject to heavy rainfall, at

    least 80 inches (2,000 mm), and in some areas over 430 inches (10,920

    mm) of rain each year. In equatorial regions, rainfall may be year round

    without apparent "wet" or "dry" seasons, although many forests do have

    seasonal rains. Even in seasonal forests, the period between rains is

    usually not long enough for the leaf litter to dry out completely. During the

    parts of the year when less rain falls, the constant cloud cover is enough to

    keep the air moist and prevent plants from drying out. Some neotropical

    rainforests rarely go a month during the year without at least 6" of rain.

    The stable climate, with evenly spread rainfall and warmth, allows most

    rainforest trees to be evergreenkeeping their leaves all year and never

    dropping all their leaves in any one season.

    Forests further from the equator, like those of Thailand, Sri Lanka,

    and Central America, where rainy seasons are more pronounced, can only

    be considered "semi-evergreen" since some species of trees may shed all

    of their leaves at the beginning of the dry season. Annual rainfall is spread

    evenly enough to allow heavy growth of broad-leafed evergreen trees, or

    at least semi-evergreen trees.

    The moisture of the rainforest from rainfall, constant cloud cover,

    and transpiration (water loss through leaves), creates intense local

    humidity. Each canopy tree transpires some 200 gallons (760 liters) of

    water annually, translating to roughly 20,000 gallons (76,000 L) of water

    transpired into the atmosphere for every acre of canopy trees. Large

    rainforests (and their humidity) contribute to the formation of rain clouds,

    and generate as much as 75 percent of their own rain. The Amazon

    rainforest is responsible for creating as much as 50 percent of its own

    precipitation.

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    Deforestation and climate change may be affecting the water cycle

    in tropical rainforests. Since the mid-1990s, rainforests around the world

    have experienced periods of severe drought, including southeast Asia in

    1997 and 2005 and the Amazon in 2005. Dry conditions, combined with

    degradation from logging and agricultural conversion, make forests more

    vulnerable to wildfire.

    G. Why Do Rainforests Have So Many Kinds Of Plants And AnimalsTropical rainforests support the greatest diversity of living organisms

    on Earth. Although they cover less than 2% of Earth's surface, rainforests

    house more than 50% of plants and animals on Earth. Here are some examples

    of the richness of rainforests:

    y rainforests have 170,000 of the world's 250,000 known plant speciesy the United States has 81 species of frogs, while Madagascar which is

    smaller than Texas, may have 300 species.

    y Europe has 321 butterfly species, while a park in the rainforest of Peru(Manu National Park) has 1300 species.

    Rainforests have an abundance of plants and animals for the following

    reasons:

    1. Climate: because rainforests are located in tropical regions, they receive alot of sunlight. This sunlight is converted to energy by plants through the

    process of photosynthesis. Since there is a lot of sunlight that means there

    is a lot of energy in the rainforest. This energy is stored in plant vegetation

    which is eaten by animals. Because there is a lot of food there are many

    species of plants and animals.

    2. Canopy: the canopy structure of the rainforest means there are more places for plants to grow and animals to live. The canopy offers new

    sources of food, shelter, and hiding places, provides another world for

    interaction with between different species. For example there are plants in

    the canopy called bromeliads that store water in their leaves. Animals like

    frogs use these pockets of water for hunting and laying their eggs.

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    CHAPTER IV

    CLOSING

    1. Tropical rainforests are forests with tall trees, warm climate, and lots of rain.In some rainforests it rains more than one inch every day.

    2. Rainforests are found in the tropics, the region between the Tropic ofCapricorn and Tropic of Cancer. In this region the sun is very strong and

    shines about the same amount of time every day all year long making the

    climate warm and stable. Rainforests are found in Africa, Asia, Australia, and

    Central and South America. The largest rainforest in the world is the Amazon

    rainforest.3. Each rainforest is unique but there are certain features common to all tropical

    rainforests.

    a. Location: rainforests lie in the "tropics"b. Rainfall: rainforests receive at least 80 inches (200 centimeters) of rain per

    year

    c. Canopy: rainforests have a canopy which is the layer of branches andleaves formed by closely spaced rainforest trees. Most of the plants and

    animals in the rainforest live in the canopy. The canopy may be 100 feet

    above the ground.

    d. Biodiversity: rainforests have a high level of biological diversity or biodiversity. Biodiversity is the name for all living things -- like plants,

    animals, and fungi -- found in an ecosystem. Scientists believe that about

    half of the plants and animals found on earth's land surface live in

    rainforests.

    e. Symbiotic relationships between species: species in the rainforest oftenwork together.

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    4. Tropical rainforests across the world are quite diverse, but share severaldefining characteristics including climate, precipitation, canopy structure,

    complex symbiotic relationships, and diversity of species.

    a. Geography and climateTropical rainforests lie in the "tropics," between the Tropic of Capricorn

    and Tropic of Cancer. In this region sunlight strikes Earth at roughly a 90-

    degree angle resulting in intense solar energy (solar energy diminishes as

    you move farther north or south).

    b. PrecipitationAn important characteristic of rainforests is apparent in their name.

    Rainforests lie in the intertropical convergence zone where intense solar

    energy produces a convection zone of rising air that loses its moisture

    through frequent rainstorms.

    5. Rainforests have an abundance of plants and animals for the followingreasons:

    Climate: because rainforests are located in tropical regions, they receive a lot

    of sunlight. This sunlight is converted to energy by plants through

    the process of photosynthesis. Since there is a lot of sunlight that

    means there is a lot of energy in the rainforest. This energy is stored

    in plant vegetation which is eaten by animals. Because there is a lot

    of food there are many species of plants and animals.

    Canopy: the canopy structure of the rainforest means there are more places

    for plants to grow and animals to live. The canopy offers new

    sources of food, shelter, and hiding places, provides another world

    for interaction with between different species. For example there are

    plants in the canopy called bromeliads that store water in their

    leaves. Animals like frogs use these pockets of water for hunting

    and laying their eggs.

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    BIBLIOGRAPHY

    Anonym1. http://en.wikipedia.org/wiki/Rainforest. Accessed at June 2

    th2010.

    Anonym 2 . http://en.wikipedia.org/wiki/Tropical_rainforest. Accessed at June 2th

    2010.

    Anonym3.http://www.srl.caltech.edu/personnel/krubal/rainforest/serve_home.htm

    l. Accessed at June 2th 2010.

    Anonym4. http://rainforests.mongabay.com/. Accessed at June 2

    th2010.