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Tropical Rain Forest Biome Sounds of the Rainforest: http://www.bbc.co.uk/nature/habitats/Tropical_and_subtropical_mo ist_broadleaf_forests Tropical Rain Forest Tropical Rain Forest Tropical rainforests lie in the "tropics", between the Tropic of Capricorn and Tropic of Cancer. Tropical Rain Forest Tropical rainforests are located near the equator. Fifty seven percent of all tropical rainforests are found in Latin America. One third of the world's tropical rainforests are in Brazil. Other tropical rainforests are located in Southeast Asia and the Pacific Islands (25% of the world's tropical rainforests) and West Africa (18%). Tropical Rain Forest Tropical Rainforest Controlled by tradewinds and doldrums Tropical Rain Forest Because of the ample solar energy, tropical rainforests are usually warm year round with temperatures from about 72-93F (22-34C) Tropical Rainforest Warm and humid all year-round because found near equator. High surface heat and humidity cause cumulus clouds to form early in the afternoons almost everyday. Humidity is between 77% and 88%. High sun angles throughout the year make the high annual temperatures with very little seasonal variation Tropical Rainforest Daily rain from 60 – 103 inches a year. In monsoon areas – there is a wet season and dry season. One part of the year a moist ocean wind creates a wet season. Another part of the year, the wind changes direction, and a dry land wind creates a dry season. Tropical Rainforest Monsoon in Mawsynram, India has an average yearly rainfall of 450 inches (37.5 ft), but all this comes in six months during the wet season! Tropical Rainforest Average temperature: 80°F. High sun angles throughout the year make the high annual temperatures with very little seasonal variation. Tropical Rain Forest Tropical rain forests are home to more species of plants and animals than all other biomes combined. Tropical Rain Forests Abiotic Factors: climate is hot and wet all year and the soil is thin and nutrient poor. Abiotic Factors Tropical Rain Forest Both tropical and temperate rainforests are very lush and wet. Rainfall falls regularly throughout the year. The tropical rainforest receives 80-400 inches of rainfall per year. Tropical Rain Forests Limiting Factor: human development Tropical rainforests comprise only 40% of the world's tropical forests and only 20% of the world's total forests. They cover 67% of the Earth's land surface. Half of the world's plant and animal species live in the tropical rainforests of the world. Thirty acres of trees are cut in the tropical rainforests every minute. As you read this, tropical rainforests are shrinking. Each second a portion of rainforest the size of a football field is destroyed or damaged. Tropical Rain Forest What makes the tropical rainforest so special and unique? Is it the diverse life? The intense vegetation? Or is it the lush tapestry of interdependent creatures? LAYERS OF A RAINFOREST EMERGENT LAYER The tallest trees are the emergents, towering as much as 200 feet above the forest floor with trunks that measure up to 16 feet around. Most of these trees are broadleaved, hardwood evergreens. Sunlight is plentiful up here. Animals found are eagles, monkeys, bats and butterflies. CANOPY LAYER This 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 treefrogs. UNDERSTORY LAYER Little sunshine reaches this area so the plants have to grow larger leaves to reach the 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. FOREST FLOOR It's very dark down here. Almost no 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. Identify the limiting factors that influence plant and animal communities. Different animals and plants live in various layers of the rainforest. Each layer is an unique community. Tropical Rainforest An important characteristic of rainforests is apparent in their name. Rainforests get around 100 inches of rain per year. Rainforests are found mainly around the equator. 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. Tropical Rain Forest 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. Tropical Rain Forest Bamboo It does very well in a moist environment with a lot of rainfall. It likes temperatures between 40 degrees Fahrenheit and 100 degrees Fahrenheit. This particular bamboo can grow anywhere between 40 feet and 80 feet in height. Tropical Rain Forest Figs are one of the most important plant species of a rainforest ecosystem. There are close to 1,000 different species of Ficus, which can be found in every major rainforest, tropical continent and islands around the world. Hundreds of animals like pigeons, parrots, hornbills, toucans, monkeys, gibbons, and fruit-eating bats, feed on the sweet fruit of the fig tree. Tropical Rainforest Bromeliads are related to the pineapple family. Their thick, waxy leaves form a bowl shape in the centre for catching rainwater. Some bromeliads can hold several gallons of water and are miniature ecosystems in themselves providing homes for several creatures including frogs and their tadpoles, salamanders, snails, beetles and mosquito larvae. Most rainforest soil is very poor with all the nutrients available largely remaining at surface level. Because of this rainforest trees have very shallow roots. Tropical Rain Forest Some very tall trees have developed ways of obtaining much needed additional support by forming buttressed roots, which grow out from the base of the trunk sometimes as high as 15 ft above the ground. These extended roots also increase the area over which nutrients can be absorbed from the soil. Tropical Rainforest Spider monkeys like to hang upside-down with all four limbs and the tail holding on to branches which makes them look like a spider They are unusual monkeys in that they have only four fingers and no thumb. Spider monkeys are heavily hunted and are in danger of becoming extinct. Tropical Rainforest A toucan's bill is sharp and has saw-like edges. The bill is used to squash the many kinds of fruit and berries he eats. Tropical Rainforest Poison-arrow frogs are about the size of a man's thumbnail (less than one inch). One frog carries enough poison to kill about 100 people. Native hunters use it on the tips of their arrows which is how the frog got its name. Tropical Rainforest Some sloths stay in the same tree for years. Their huge hooked claws and long arms allow them to spend most of their time hanging upside-down from trees. Since they have a slow metabolism, they need very little food. Sloths are extremely slowmoving mammals Sloths also sleep upside-down for up to 18 hours at a time. Mothers also give birth to babies upside-down. Tropical Rainforest Interdependence—whereby all species are to some extent be dependent on one another— is a key characteristic of the rainforest ecosystem. Biological interdependency takes many forms in the forest, from species relying on other species for pollination and seed dispersal to predator-prey relationships to symbiotic relationships. Tropical Rainforest Each species that disappears from the ecosystem may weaken the survival chances of another, while the loss of a keystone species—an organism that links many other species together, much like the keystone of an arch—could cause a significant disruption in the functioning of the entire system. Tropical Rainforest For example, Brazil nut trees (Bertholletia excelsa) are dependent on several animal species for their survival. These large canopy trees found in the Amazon rainforest rely on the agouti, a ground-dwelling rodent, for a key part of their life cycle. The agouti is the only animal with teeth strong enough to open their grapefruitsized seed pods. While the agouti eats some of the Brazil nut's seeds, it also scatters the seeds across the forest by burying caches far away from the parent tree. These seeds then germinate and form the next generation of trees. For pollination, Brazil nut trees are dependent on Euglossine orchid bees. Without these large-bodied bees, Brazil nut reproduction is not possible. For this reason, there has been little success growing Brazil nut trees in plantations—they only appear to grow in primary rainforest. Home Home Science Notes Science Notes Web Links Web Links Biomes Biomes Lessons Lessons Tropical Rainforest Abiotic Factor: soil Why is the soil in the tropical rainforest so nutrient poor? Over the years, nutrients have been washed out of the soil by rain. How are nutrients returned to the soil? On the forest floor, decomposers immediately break down organic matter, making nutrients available to the plants again. Tropical Rainforest The rain forest's lush vegetation gets its nutrients at the soil's surface. Heavy rains, high humidity and high temperatures lead to rapid decay of leaves and limbs that fall from the canopy to the floor. But the fast rate of decay keeps humus, the darkcolored, nutrient-rich upper soil from forming. So all soil nutrients are near the top layer, not deep into the soil. And to be fertile, soil needs humus. Tropical Rainforest Tropical rain forests are very important to the overall health of the planet Earth, and are responsible for replenishing a significant portion of the atmosphere’s oxygen supply. Tropical Rainforest Deforestation: Farmers that live in the tropical areas clear the land to farm and to sell the valuable wood. Since the soil has only a thin layer of nutrients, farmers can only grow crops in an area for only a few years. After a while, more land must be cleared to grow crops or grow cattle. For example, the thin nutrient soil can only support cattle for a year So old pastures are abandoned. More rain forest is then cut for replacement pastures. As a result, tropical rainforest habitats are being destroyed. In 1950 rain forests covered 15 percent of the earth. Today, only a shrinking six percent. Limiting Factor: Deforestation Tropical Rainforest Tropical Rainforest In 1950, we had lost only 8% of the tropical rainforests that existed in 1750; by 2000, we had lost 30% of what existed in 1750, and we are now losing a football field of rainforest every second. -- from the Awakening the Dreamer, Changing the Dream Symposium Tropical Rain Forests Are all Tropical Forests, Rainforests? Only a small percentage of the tropical forests are rainforests. To be a tropical rainforest, forested areas must: Lie between the Tropic of Cancer and the Tropic of Capricorn. Receive rainfall regularly throughout the year (80-400 inches per year). Remain warm and frost free all year long (mean temperatures are between 70° and 85°F) with very little daily fluctuation. Tropical Rain Forest Consequently, many forested areas in the tropics are not rainforests. Forests that receive irregular rainfall (monsoons followed by a dry season) are moist deciduous forests. Trees in these forests may drop their leaves in the dry season. These are called tropical dry forests. Tropical Rainforest Resources http://www.mbgnet.net/sets/rforest/index.htm http://www.srl.caltech.edu/personnel/krubal/rainforest/Edit560s6/www/pl ants/bromeliads.html http://www.srl.caltech.edu/personnel/krubal/rainforest/Edit560s6/www/w hlayers.html http://curriculum.calstatela.edu/courses/builders/lessons/less/biomes/rai nforest/tropi_rain/rainweb.html