• rain forest
    Kapok trees are keystone species in many rain forest ecosystems.
    Species-Rich, Soil-Poor 
    The soil of most tropical rain forests contains few nutrients. The rich biodiversity in the canopy and quick decomposition from fungi and bacteria prevent the accumulation of nutrient-rich humus. Nutrients are confined to the rain forest’s thin layer of topsoil. For this reason, most of the towering trees in tropical rain forests have very shallow, widespread root systems called “buttress roots.”
    Slow Rain 
    Rain forests are so densely packed with vegetation that a drop of rain falling from the forest’s emergent layer can take 10 minutes to reach the forest floor.
    Jungles and Rain Forests 
    Jungles and rain forests are very, very similar. The main difference is that rain forests have thick canopies and taller trees. Jungles have more light and denser vegetation in the understory.
    Drip Tips 
    Many plants in the humid rain forest canopy are pointed, so that rain can run off the tips of the leaves. These “drip tips” keep the leaves dry and free of mold.
    A rain forest is an area of tall, mostly evergreen trees and a high amount of rainfall. 
     
    Rain forests are Earth’s oldest living ecosystems, with some surviving in their present form for at least 70 million years. They are incredibly diverse and complex, home to more than half of the world’s plant and animal species—even though they cover just 6% of Earth’s surface. This makes rain forests astoundingly dense with flora and fauna; a 10-square-kilometer (4-square-mile) patch can contain as many as 1,500 flowering plants, 750 species of trees, 400 species of birds and 150 species of butterflies. 
     
    Rain forests thrive on every continent except Antarctica. The largest rain forests on Earth surround the Amazon River in South America and the Congo River in Africa. The tropical islands of Southeast Asia and parts of Australia support dense rain forest habitats. Even the cool evergreen forests of North America’s Pacific Northwest and Northern Europe are a type of rain forest.
     
    Rain forests’ rich biodiversity is incredibly important to our well-being and the well-being of our planet. Rain forests help regulate our climate and provide us with everyday products. 
     
    Unsustainable industrial and agricultural development, however, has severely degraded the health of the world’s rain forests. Citizens, governments, intergovernmental organizations, and conservation groups are working together to protect these invaluable but fragile ecosystems. 
     
    Rain Forest Structure 
     
    Most rain forests are structured in four layers: emergent, canopy, understory, and forest floor. Each layer has unique characteristics based on differing levels of water, sunlight, and air circulation. While each layer is distinct, they exist in an interdependent system: processes and species in one layer influence those in another. 
     
    Emergent Layer 
    The top layer of the rain forest is the emergent layer. Here, trees as tall as 60 meters (200 feet) dominate the skyline. Foliage is often sparse on tree trunks, but spreads wide as the trees reach the sunny upper layer, where they photosynthesize the sun’s rays. Small, waxy leaves help trees in the emergent layer retain water during long droughts or dry seasons. Lightweight seeds are carried away from the parent plant by strong winds. 
     
    In the Amazon rain forest, the towering trees of the emergent layer include the Brazil nut tree and the kapok tree. The Brazil nut tree, a vulnerable species, can live up to 1,000 years in undisturbed rain forest habitats. Unlike many rain forest species, both the Brazil nut tree and the kapok tree are deciduous—they shed their leaves during the dry season. 
     
    Animals often maneuver through the emergent layer’s unstable topmost branches by flying or gliding. Animals that can’t fly or glide are usually quite small—they need to be light enough to be supported by a tree’s slender uppermost layers.
     
    The animals living in the emergent layer of the Amazon rain forest include birds, bats, gliders, and butterflies. Large raptors, such as white-tailed hawks and harpy eagles, are its top predators. 
     
    In rain forests on the island of New Guinea, pygmy gliders populate the emergent layer. Pygmy gliders are small rodents that get their name from the way flaps of skin between their legs allow them to glide from branch to branch. 
     
    Bats are the most diverse mammal species in most tropical rain forests, and they regularly fly throughout the emergent, canopy, and understory layers. One of the world’s largest species of bat, the Madagascan flying fox (found on the African island of Madagascar), for instance, is an important pollinator that mainly feeds on juice from fruit, but will chew flowers for their nectar
     
    Canopy Layer 
    Beneath the emergent layer is the canopy, a deep layer of vegetation roughly 6 meters (20 feet) thick. The canopy’s dense network of leaves and branches forms a roof over the two remaining layers. 
     
    The canopy blocks winds, rainfall, and sunlight, creating a humid, still, and dark environment below. Trees have adapted to this damp environment by producing glossy leaves with pointed tips that repel water. 
     
    While trees in the emergent layer rely on wind to scatter their seeds, many canopy plants, lacking wind, encase their seeds in fruit. Sweet fruit entices animals, which eat the fruit and deposit seeds on the forest floor as droppings. Fig trees, common throughout most of the world’s tropical rain forests, may be the most familiar fruit tree in the canopy.
     
    With so much food available, more animals live in the canopy than any other layer in the rain forest. The dense vegetation dulls sound, so many—but not all—canopy dwellers are notable for their shrill or frequent vocalizing. In the Amazon rain forest, canopy fruit is snatched up in the large beaks of screeching scarlet macaws and keel-billed toucans, and picked by barking spider and howler monkeys. The silent two-toed sloth chews on the leaves, shoots, and fruit in the canopy. 
     
    Thousands and thousands of insect species can also be found in the canopy, from bees to beetles, borers to butterflies. Many of these insects are the principal diet of the canopy’s reptiles, including the "flying" draco lizards of Southeast Asia.
     
    Understory Layer
    Located several meters below the canopy, the understory is an even darker, stiller, and more humid environment. Plants here, such as palms and philodendrons, are much shorter and have larger leaves than plants that dominate the canopy. Understory plants’ large leaves catch the minimal sunlight reaching beyond the dense canopy. 
     
    Understory plants often produce flowers that are large and easy to see, such as Heliconia, native to the Americas and the South Pacific. Others have a strong smell, such as orchids. These features attract pollinators even in the understory’s low-light conditions.
     
    The fruit and seeds of many understory shrubs in temperate rain forests are edible. The temperate rain forests of North America, for example, bloom with berries. 
     
    Animals call the understory home for a variety of reasons. Many take advantage of the dimly lit environment for camouflage. The spots on a jaguar (found in the rain forests of Central and South America) may be mistaken for leaves or flecks of sunlight, for instance. The green mamba, one of the deadliest snakes in the world, blends in with foliage as it slithers up branches in the Congo rain forest. Many bats, birds, and insects prefer the open airspace the understory offers. Amphibians, such as dazzlingly colored tree frogs, thrive in the humidity because it keeps their skin moist. 
     
    Central Africa’s tropical rain forest canopies and understories are home to some of the most endangered and familiar rain forest animals—such as forest elephants, pythons, antelopes, and gorillas. Gorillas, a critically endangered species of primate, are crucial for seed dispersal. Gorillas are herbivores that move throughout the dark, dense rain forest as well as more sun-dappled swamps and jungles. Their droppings disperse seeds in these sunny areas where new trees and shrubs can take root. In this way, gorillas are keystone species in many African rain forest ecosystems.
     
    Forest Floor Layer 
    The forest floor is the darkest of all rain forest layers, making it extremely difficult for plants to grow. Leaves that fall to the forest floor decay quickly. 
     
    Decomposers, such as termites, slugs, scorpions, worms, and fungi, thrive on the forest floor. Organic matter falls from trees and plants, and these organisms break down the decaying material into nutrients. The shallow roots of rain forest trees absorb these nutrients, and dozens of predators consume the decomposers!
     
    Animals such as wild pigs, armadillos, and anteaters forage in the decomposing brush for these tasty insects, roots and tubers of the South American rain forest. Even larger predators, including leopards, skulk in the darkness to surprise their prey. Smaller rodents, such as rats and lowland pacas (a type of striped rodent indigenous to Central and South America), hide from predators beneath the shallow roots of trees that dominate the canopy and emergent layer. 
     
    Rivers that run through some tropical rain forests create unusual freshwater habitats on the forest floor. The Amazon River, for instance, is home to the boto, or pink river dolphin, one of the few freshwater dolphin species in the world. The Amazon is also home to black caimans, large reptiles related to alligators, while the Congo River is home to the caimans’ crocodilian cousin, the Nile crocodile. 
     
    Types of Rain Forests
     
    Tropical Rain Forests
    Tropical rain forests are mainly located between the latitudes of 23.5°N (the Tropic of Cancer) and 23.5°S (the Tropic of Capricorn)—the tropics. Tropical rain forests are found in Central and South America, western and central Africa, western India, Southeast Asia, the island of New Guinea, and Australia. 
     
    Sunlight strikes the tropics almost straight on, producing intense solar energy that keeps temperatures high, between 21° and 30°C (70° and 85°F). High temperatures keep the air warm and wet, with an average humidity of between 77% and 88%. Such humid air produces extreme and frequent rainfall, ranging between 200-1000 centimeters (80-400 inches) per year. Tropical rain forests are so warm and moist that they produce as much as 75% of their own rain through evaporation and transpiration
     
    Such ample sunlight and moisture are the essential building blocks for tropical rain forests’ diverse flora and fauna. Roughly half of the world’s species can be found here, with an estimated 40 to 100 or more different species of trees present in each hectare. 
     
    Tropical rain forests are the most biologically diverse terrestrial ecosystems in the world. The Amazon rain forest is the world’s largest tropical rain forest. It is home to around 40,000 plant species, nearly 1,300 bird species, 3,000 types of fish, 427 species of mammals, and 2.5 million different insects. Red-bellied piranhas and pink river dolphins swim its waters. Jewel-toned parrots squawk and fly through its trees. Poison dart frogs warn off predators with their bright colors. Capuchin and spider monkeys swing and scamper through the branches of the rain forest’s estimated 400 billion trees. Millions of mushrooms and other fungi decompose dead and dying plant material, recycling nutrients to the soil and organisms in the understory. The Amazon rain forest is truly an ecological kaleidoscope, full of colorful sights and sounds.
     
    Temperate Rain Forests 
    Temperate rain forests are located in the mid-latitudes, where temperatures are much more mild than the tropics. Temperate rain forests are found mostly in coastal, mountainous areas. These geographic conditions help create areas of high rainfall. Temperate rain forests can be found on the coasts of the Pacific Northwest in North America, Chile, the United Kingdom, Norway, Japan, New Zealand, and southern Australia. 
     
    As their name implies, temperate rain forests are much cooler than their tropical cousins, averaging between 10° and 21°C (50° and 70°F). They are also much less sunny and rainy, receiving anywhere between 150-500 centimeters (60-200 inches) of rain per year. Rainfall in these forests is produced by warm, moist air coming in from the coast and being trapped by nearby mountains. 
     
    Temperate rain forests are not as biologically diverse as tropical rain forests. They are, however, home to an incredible amount of biological productivity, storing up to 500-2000 metric tons of leaves, wood, and other organic matter per hectare (202-809 metric tons per acre). Cooler temperatures and a more stable climate slow down decomposition, allowing more material to accumulate. The old-growth forests of the Pacific Northwest, for example, produce three times the biomass (living or once-living material) of tropical rain forests. 
     
    This productivity allows many plant species to grow for incredibly long periods of time. Temperate rain forest trees such as the coast redwood in the U.S. state of California and the alerce in Chile are among the oldest and largest tree species in the world. 
     
    The animals of the temperate rain forest are mostly made up of large mammals and small birds, insects, and reptiles. These species vary widely between rain forests in different world regions. Bobcats, mountain lions, and black bears are major predators in the rain forests of the Pacific Northwest. In Australia, ground dwellers such as wallabies, bandicoots, and potoroos (small marsupials that are among Australia’s most endangered animals) feast on the foods provided by the forest floor. Chile’s rain forests are home to a number of unique birds such as the Magellanic woodpecker and the Juan Fernández firecrown, a hummingbird species that has a crown of color-changing feathers. 
     
    People and the Rain Forest
     
    Rain forests have been home to thriving, complex communities for thousands of years. For instance, unique rain forest ecosystems have influenced the diet of cultures from Africa to the Pacific Northwest.
     
    Mbuti
    The Mbuti, a community indigenous to the Ituri rain forest in Central Africa, have traditionally been hunter-gatherers. Their diet consists of plants and animals from every layer of the rain forest. 
     
    From the forest floor, the Mbuti hunt fish and crabs from the Ituri River (a tributary of the Congo), as well as gather berries from low-lying shrubs. The giant forest hog, a species of wild boar, is also frequently targeted by Mbuti hunters, although this species is hunted for sale more often than food. From the understory, the Mbuti may gather honey from bee hives, or hunt monkeys. From the canopy and emergent layers, Mbuti hunters may set nets or traps for birds. 
     
    Although they are a historically nomadic society, agriculture has become a way of life for many Mbuti communities today as they trade and barter with neighboring agricultural groups such as the Bantu for crops such as manioc, nuts, rice, and plantains. 
     
    Chimbu
    The Chimbu people live in the highland rain forest on the island of New Guinea. The Chimbu practice subsistence agriculture through shifting cultivation. This means they have gardens on arable land that has been cleared of vegetation. A portion of the plot may be left fallow for months or years. The plots are never abandoned and are passed on within the family.
     
    Crops harvested in Chimbu garden plots include sweet potatoes, bananas, and beans. The Chimbu also maintain livestock, particularly pigs. In addition to their own diet, pigs are valuable economic commodities for trade and sale. 
     
    Tlingit
    The temperate rain forest of the northwest coast of North America is the home of the Tlingit. The Tlingit enjoy a diverse diet, relying on both marine and freshwater species, as well as game from inland forests. 
     
    Due to bountiful Pacific inlets, rivers, and streams, the traditional Tlingit diet consists of a wide variety of aquatic life: crab, shrimp, clams, oysters, seals, and fish such as herring, halibut, and, crucially, salmon. Kelps and other seaweeds can be harvested and eaten in soups or dried. One familiar Tlingit saying is “When the tide is out, our table is set.” 
     
    In more inland areas, historic Tlingit hunters may have targeted deer, elk, rabbit, and mountain goats. Plants gathered or harvested include berries, nuts, and wild celery. 
     
    Yanomami
    The Yanomami are a people and culture native to the northern Amazon rain forest, spanning the border between Venezuela and Brazil. Like the Chimbu, the Yanomami practice both hunting and shifting-cultivation agriculture.
     
    Game hunted by the Yanomami include deer, tapirs (an animal similar to a pig), monkeys, birds, and armadillos. The Yanomami have hunting dogs to help them search the understory and forest floor for game. 
     
    The Yanomami practice slash-and-burn agriculture to clear the land of vegetation prior to farming. Crops grown include cassava, banana, and corn. In addition to food crops, the Yanomami also cultivate cotton, which is used for hammocks, nets, and clothing. 
     
    Benefits of Rain Forests 
     
    Ecological Well-Being
    Rain forests are critically important to the well-being of our planet. Tropical rain forests encompass approximately 1.2 billion hectares (3 billion acres) of vegetation and are sometimes described as the Earth’s thermostat
     
    Rain forests produce about 20% of our oxygen and store a huge amount of carbon dioxide, drastically reducing the impact of greenhouse gas emissions. Massive amounts of solar radiation are absorbed, helping regulate temperatures around the globe. Taken together, these processes help to stabilize Earth’s climate. 
     
    Rain forests also help maintain the world’s water cycle. More than 50% of precipitation striking a rain forest is returned to the atmosphere by evapotranspiration, helping regulate healthy rainfall around the planet. Rain forests also store a considerable percentage of the world’s freshwater, with the Amazon Basin alone storing one-fifth. 
     
    Human Well-Being
    Rain forests provide us with many products that we use every day. Tropical woods such as teak, balsa, rosewood, and mahogany are used in flooring, doors, windows, boatbuilding, and cabinetry. Fibers such as raffia, bamboo, kapok, and rattan are used to make furniture, baskets, insulation, and cord. Cinnamon, vanilla, nutmeg, and ginger are just a few spices of the rain forest. The ecosystem supports fruits including bananas, papayas, mangos, cocoa and coffee beans. 
     
    Rain forests also provide us with many medicinal products. According to the U.S. National Cancer Institute, 70% of plants useful in the treatment of cancer are found only in rain forests. Rain forest plants are also used in the creation of muscle relaxants, steroids, and insecticides. They are used to treat asthma, arthritis, malaria, heart disease, and pneumonia. The importance of rain forest species in public health is even more incredible considering that less than one percent of rain forest species have been analyzed for their medicinal value. 
     
    Even rain forest fungi can contribute to humanity’s well-being. A mushroom discovered in the tropical rain forest of Ecuador, for example, is capable of consuming polyurethane—a hard, durable type of plastic used in everything from garden hoses to carpets to shoes. The fungi can even consume the plastic in an oxygen-free environment, leading many environmentalists and businesses to invest in research to investigate if the fungi can help reduce waste in urban landfills. 
     
    Threats to Rain Forests
     
    Rain forests are disappearing at an alarmingly fast pace, largely due to human development over the past few centuries. Once covering 14% of land on Earth, rain forests now make up only 6%. Since 1947, the total area of tropical rain forests has probably been reduced by more than half, to about 6.2 to 7.8 million square kilometers (3 million square miles). 
     
    Many biologists expect rain forests will lose 5-10% of their species each decade. Rampant deforestation could cause many important rain forest habitats to disappear completely within the next hundred years. 
     
    Such rapid habitat loss is due to the fact that 40 hectares (100 acres) of rain forest are cleared every minute for agricultural and industrial development. In the Pacific Northwest’s rain forests, logging companies cut down trees for timber while paper industries use the wood for pulp. In the Amazon rain forest, large-scale agricultural industries, such as cattle ranching, clear huge tracts of forests for arable land. In the Congo rain forest, roads and other infrastructure development have reduced habitat and cut off migration corridors for many rain forest species. Throughout both the Amazon and Congo, mining and logging operations clear-cut to build roads and dig mines. Some rain forests are threatened by massive hydroelectric power projects, where dams flood acres of land. Development is encroaching on rain forest habitats from all sides. 
     
    Economic inequalities fuel this rapid deforestation. Many rain forests are located in developing countries with economies based on natural resources. Wealthy nations drive demand for products, and economic development increases energy use. These demands encourage local governments to develop rain forest acreage at a fraction of its value. Impoverished people who live on or near these lands are also motivated to improve their lives by converting forests into subsistence farmland.
     
    Rain Forest Conservation
     
    Many individuals, communities, governments, intergovernmental organizations, and conservation groups are taking innovative approaches to protect threatened rain forest habitats. 
     
    Many countries are supporting businesses and initiatives that promote the sustainable use of their rain forests. Costa Rica is a global pioneer in this field, investing in ecotourism projects that financially contribute to local economies and the forests they depend on. The country also signed an agreement with an American pharmaceutical company, Merck, which sets aside a portion of the proceeds from rain forest-derived pharmaceutical compounds to fund conservation projects. 
     
    Intergovernmental groups address rain forest conservation at a global scale. The United Nations’ REDD (Reducing Emissions from Deforestation and forest Degradation) Program, for example, offers financial incentives for reducing carbon emissions created by deforestation to 58 member countries. The Democratic Republic of the Congo used REDD funds to create an online National Forest Monitoring System that tracks and maps data on logging concessions, deforestation in protected areas, and national forestry sector measures. REDD funds were also used to investigate best practices in solving land disputes in Cambodia, which lacks proper forest zoning and boundary enforcement. 
     
    Nonprofit organizations are tackling rain forest conservation through a variety of different approaches. The Rainforest Trust, for example, supports local conservation groups around the world in purchasing and managing critically important habitats. In Ecuador, the Rainforest Trust worked with the Fundación Jocotoco to acquire 495 more hectares (1,222 more acres) for the Río Canandé Reserve, considered to have one of the highest concentrations of endemic and threatened species in the world. Partnering with Burung Indonesia, the Trust created a 8,900-hectare (22,000-acre) reserve on Sangihe Island to protect the highest concentration of threatened bird species in Asia. 
     
    The Rainforest Alliance is a nonprofit organization that helps businesses and consumers know that their products conserve rather than degrade rain forests. Products that bear the Rainforest Alliance seal contain ingredients from farms or forests that follow strict guidelines designed to support the sustainable development of rain forests and local communities. The Alliance also allows tourism businesses use of their seal after they complete an education program on efficiency and sustainability. In turn, this seal allows tourists to make ecologically smart vacation plans. 
  • Term Part of Speech Definition Encyclopedic Entry
    abandoned Adjective

    deserted.

    absorb Verb

    to soak up.

    accumulate Verb

    to gather or collect.

    adapt Verb

    to adjust to new surroundings or a new situation.

    agricultural development Noun

    modern farming methods that include mechanical, chemical, engineering and technological methods. Also called industrial agriculture.

    agriculture Noun

    the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching).

    Encyclopedic Entry: agriculture
    air circulation Noun

    natural or artificial movement of air in a closed environment. Also called ventilation.

    ample Adjective

    plenty or more than enough.

    analyze Verb

    to study in detail.

    aquatic Adjective

    having to do with water.

    arable Adjective

    land able to produce crops.

    arthritis Noun

    inflammation of a joint often resulting in pain and stiffness.

    assess Verb

    to evaluate or determine the amount of.

    asthma Noun

    disease that makes it difficult to breathe.

    astound Verb

    to shock and amaze.

    atmosphere Noun

    layers of gases surrounding a planet or other celestial body.

    Encyclopedic Entry: atmosphere
    aversion Noun

    strong dislike or repulsion.

    basin Noun

    a dip or depression in the surface of the land or ocean floor.

    Encyclopedic Entry: basin
    beak Noun

    hard, protruding jaws of a bird.

    biodiversity Noun

    all the different kinds of living organisms within a given area.

    Encyclopedic Entry: biodiversity
    biologist Noun

    scientist who studies living organisms.

    biomass Noun

    living organisms, and the energy contained within them.

    border Noun

    natural or artificial line separating two pieces of land.

    Encyclopedic Entry: border
    boundary Noun

    line separating geographical areas.

    Encyclopedic Entry: boundary
    bountiful Adjective

    plentiful.

    brush Noun

    dense growth of bushes, shrubs, and small trees.

    business Noun

    sale of goods and services, or a place where such sales take place.

    camouflage Noun

    tactic that organisms use to disguise their appearance, usually to blend in with their surroundings.

    Encyclopedic Entry: camouflage
    cancer Noun

    growth of abnormal cells in the body.

    canopy Noun

    one of the top layers of a forest, formed by the thick leaves of very tall trees.

    carbon emission Noun

    carbon compound (such as carbon dioxide) released into the atmosphere, often through human activity such as the burning of fossil fuels such as coal or gas.

    cattle Noun

    cows and oxen.

    citizen Noun

    member of a country, state, or town who shares responsibilities for the area and benefits from being a member.

    climate Noun

    all weather conditions for a given location over a period of time.

    Encyclopedic Entry: climate
    coast Noun

    edge of land along the sea or other large body of water.

    Encyclopedic Entry: coast
    complex Adjective

    complicated.

    concentration Noun

    measure of the amount of a substance or grouping in a specific place.

    concession Noun space or privilege secured within a larger space for a specific business or service.
    conservation Noun

    management of a natural resource to prevent exploitation, destruction, or neglect.

    Encyclopedic Entry: conservation
    consume Verb

    to use up.

    consumer Noun

    person who uses a good or service.

    continent Noun

    one of the seven main land masses on Earth.

    Encyclopedic Entry: continent
    convert Verb

    to change from one thing to another.

    critically endangered Noun

    level of conservation between "endangered" and "extinct in the wild."

    crocodilian adjective, noun

    order of reptiles that includes crocodiles, alligators, caimans, and gharials.

    crop Noun

    agricultural produce.

    Encyclopedic Entry: crop
    crucial Adjective

    very important.

    culture Noun

    learned behavior of people, including their languages, belief systems, social structures, institutions, and material goods.

    dam Noun

    structure built across a river or other waterway to control the flow of water.

    damp Adjective

    slightly wet.

    decade Noun

    10 years.

    decay Verb

    to rot or decompose.

    deciduous Adjective

    type of plant that sheds its leaves once a year.

    decomposer Noun

    organism that breaks down dead organic material.

    deforestation Noun

    destruction or removal of forests and their undergrowth.

    degrade Verb

    to lower the quality of something.

    dense Adjective

    having parts or molecules that are packed closely together.

    development Noun

    construction or preparation of land for housing, industry, or agriculture.

    diet Noun

    foods eaten by a specific group of people or other organisms.

    Encyclopedic Entry: diet
    dispersal Noun

    spread of something to a new area.

    dispute Noun

    debate or argument.

    distinct Adjective

    unique or identifiable.

    diverse Adjective

    varied or having many different types.

    dominate Verb

    to overpower or control.

    droppings Plural Noun

    dung of certain animals, usually in pellet form.

    drought Noun

    period of greatly reduced precipitation.

    Encyclopedic Entry: drought
    dry season Noun

    time of year with little precipitation.

    durable Adjective

    strong and long-lasting.

    economic Adjective

    having to do with money.

    ecosystem Noun

    community and interactions of living and nonliving things in an area.

    Encyclopedic Entry: ecosystem
    ecotourism Noun

    act and industry of traveling for pleasure with concern for minimal environmental impact.

    edible Adjective

    able to be eaten and digested.

    efficiency Noun

    ability to accomplish a task.

    emergent layer Noun

    uppermost layer of a forest, where sunlight is plentiful and trees tower on thin trunks.

    encase Verb

    to enclose or completely confine.

    encourage Verb

    to inspire or support a person or idea.

    encroach Verb

    to trespass or enter upon the property or rights of another.

    endanger Verb

    to put at risk.

    endemic Adjective

    native to a specific geographic space.

    enforce Verb

    to compel or force a course of action.

    entice Verb

    to lure, or lead on with hope and desire.

    environment Noun

    conditions that surround and influence an organism or community.

    essential Adjective

    needed.

    evaporation Noun

    process by which liquid water becomes water vapor.

    Encyclopedic Entry: evaporation
    evapotranspiration Noun

    loss of water from the Earth's soil by evaporation into the atmosphere and transpiration by plants.

    evergreen Noun

    tree that does not lose its leaves.

    extreme Adjective

    unusual or extraordinary.

    farmland Noun

    area used for agriculture.

    fauna Noun

    animals associated with an area or time period.

    financial Adjective

    having to do with money.

    flora Noun

    plants associated with an area or time period.

    foliage Noun

    leaves of a plant, or the leaves and branches of a tree or shrub.

    food crop Noun

    plants grown and harvested for human consumption.

    forage Verb

    to search for food or other needs.

    forest Noun

    ecosystem filled with trees and underbrush.

    forest floor Noun

    ground-level layer of a forest.

    forestry Noun

    management, cultivation, and harvesting of trees and other vegetation in forests.

    fraction Noun

    portion or section.

    fragile Noun

    delicate or easily broken.

    frequent Adjective

    often.

    freshwater Adjective

    having to do with a habitat or ecosystem of a lake, river, or spring.

    fund Verb

    to give money to a program or project.

    fungi Plural Noun

    (singular: fungus) organisms that survive by decomposing and absorbing nutrients in organic material such as soil or dead organisms.

    game Noun

    wild animals hunted for food.

    government Noun

    system or order of a nation, state, or other political unit.

    greenhouse gas Noun

    gas in the atmosphere, such as carbon dioxide, methane, water vapor, and ozone, that absorbs solar heat reflected by the surface of the Earth, warming the atmosphere.

    habitat Noun

    environment where an organism lives throughout the year or for shorter periods of time.

    Encyclopedic Entry: habitat
    harvest Noun

    the gathering and collection of crops, including both plants and animals.

    herbivore Noun

    organism that eats mainly plants and other producers.

    Encyclopedic Entry: herbivore
    historic Adjective

    significant or important to history.

    humid Adjective

    containing a large amount of water vapor.

    hunter-gatherer Noun

    person who gets food by using a combination of hunting, fishing, and foraging.

    hydroelectric power Noun

    the rate of producing, transferring, or using hydroelectric energy, often measured in kW or mW.

    impoverished Adjective

    very poor.

    incentive Noun

    offer or encouragement to complete a task.

    increase Verb

    to add or become larger.

    industrial Adjective

    having to do with factories or mechanical production.

    infrastructure Noun

    structures and facilities necessary for the functioning of a society, such as roads.

    initiative Noun

    first step or move in a plan.

    inlet Noun

    small indentation in a shoreline.

    innovative Adjective

    new, advanced, or original.

    insecticide Noun

    chemical substance used to kill insects.

    insulation Noun

    material used to keep an object warm.

    interdependent Adjective

    two or more individuals or communities that rely on each other for survival.

    intergovernmental Adjective

    having to do with the national governments of more than one state.

    invest Verb

    to contribute time or money.

    investigate Verb

    to study or examine in order to learn a series of facts.

    jungle Noun

    tropical ecosystem filled with trees and underbrush.

    kaleidoscope Noun

    complex, constantly changing pattern of shapes and colors.

    keystone species Noun

    organism that has a major influence on the way its ecosystem works.

    Encyclopedic Entry: keystone species
    landfill Noun

    site where garbage is layered with dirt and other absorbing material to prevent contamination of the surrounding land or water.

    latitude Noun

    distance north or south of the Equator, measured in degrees.

    Encyclopedic Entry: latitude
    livestock noun, plural noun

    animals raised for sale and profit.

    logging Noun

    industry engaged in cutting down trees and moving the wood to sawmills.

    lucrative Adjective

    profitable or money-making.

    lung Noun

    organ in an animal that is necessary for breathing.

    macaw Noun

    long-tailed parrot native to the Americas.

    malaria Noun

    infectious disease caused by a parasite carried by mosquitoes.

    mammal Noun

    animal with hair that gives birth to live offspring. Female mammals produce milk to feed their offspring.

    maneuver Noun

    a skillful movement.

    marine Adjective

    having to do with the ocean.

    marsupial Noun

    mammal that carries its young in a pouch on the mother's body.

    massive Adjective

    very large or heavy.

    medicinal Adjective

    having to do with curative therapy (medicine).

    migration corridor Noun

    area connecting wildlife habitats disturbed and interrupted by human activity. Also called a green corridor.

    mining Noun

    process of extracting ore from the Earth.

    monitor Noun

    screen used to display an electronic device's video output.

    nation Noun

    political unit made of people who share a common territory.

    Encyclopedic Entry: nation
    natural resource Noun

    a material that humans take from the natural environment to survive, to satisfy their needs, or to trade with others.

    nectar Noun

    sweet plant material that attracts pollinators.

    nomadic Adjective

    having to do with a way of life lacking permanent settlement.

    nonprofit organization Noun

    business that uses surplus funds to pursue its goals, not to make money.

    nutrient Noun

    substance an organism needs for energy, growth, and life.

    Encyclopedic Entry: nutrient
    oil Noun

    fossil fuel formed from the remains of marine plants and animals. Also known as petroleum or crude oil.

    old-growth forest Noun

    collection of trees and shrubs that has not been harvested for timber or other uses in about 200 years, although definitions vary. Also called a primeval forest, primal forest, or ancient woodland.

    organic Adjective

    composed of living or once-living material.

    organism Noun

    living or once-living thing.

    pharmaceutical Noun

    drug or having to do with drugs and medications.

    philodendron Noun

    plant with large, flat leaves native to the Americas.

    photosynthesis Noun

    process by which plants turn water, sunlight, and carbon dioxide into water, oxygen, and simple sugars.

    pioneer Noun

    person who is among the first to do something.

    plastic Noun

    chemical material that can be easily shaped when heated to a high temperature.

    pneumonia Noun

    infection where lungs fill with fluid.

    pollinator Noun

    animal, object, or force such as wind that transfers pollen from one plant to another, allowing seeds to develop.

    polyurethane Noun

    type of plastic used as a foam (for packing), fiber (for clothing), hard lining (for coatings), or flexible material (similar to rubber).

    precipitation Noun

    all forms in which water falls to Earth from the atmosphere.

    Encyclopedic Entry: precipitation
    predator Noun

    animal that hunts other animals for food.

    prey Noun

    animal that is hunted and eaten by other animals.

    primate Noun

    type of mammal, including humans, apes, and monkeys.

    principal Adjective

    leading or dominant.

    prior Adjective

    before or ahead of.

    promote Verb

    to encourage or help.

    public health Noun

    services that protect the health of an area, particularly sanitation, immunization, and environmental safety.

    pulp Noun

    moist wood fibers from which paper is made.

    rainfall Noun

    amount of precipitation that falls in a specific area during a specific time.

    rain forest Noun

    area of tall, mostly evergreen trees and a high amount of rainfall.

    Encyclopedic Entry: rain forest
    rampant Adjective

    unrestrained or widespread.

    ranching Noun

    practice of raising livestock for human use, such as food or clothing.

    Encyclopedic Entry: ranching
    rapid Adjective

    very fast.

    raptor Noun

    bird of prey, or carnivorous bird.

    reduce Verb

    to lower or lessen.

    regulate Verb

    to determine and administer a set of rules for an activity.

    repel Verb

    to resist or push back.

    research Noun

    scientific observations and investigation into a subject, usually following the scientific method: observation, hypothesis, prediction, experimentation, analysis, and conclusion.

    rodent Noun

    order of mammals often characterized by long teeth for gnawing and nibbling.

    scamper Verb

    to quickly and playfully run from one place to another.

    screech Verb

    to make a rough, high-pitched cry.

    seal Noun

    formal or official stamp, emblem, or other mark.

    seaweed Noun

    marine algae. Seaweed can be composed of brown, green, or red algae, as well as "blue-green algae," which is actually bacteria.

    sector Noun

    section or a part of something.

    seed Noun

    part of a plant from which a new plant grows.

    severe Adjective

    harsh.

    shifting cultivation Noun

    type of agriculture where a field or plot is cleared, cropped, and harvested until its fertility is exhausted. Also called slash-and-burn, milpa and swidden.

    shrill Adjective

    having to do with a high-pitched, piercing sound.

    shrub Noun

    type of plant, smaller than a tree but having woody branches.

    skulk Verb

    to move in a secretive or stealthy manner.

    slash-and-burn Noun

    method of agriculture where trees and shrubs are cleared and burned to create cropland.

    slither Verb

    to slide along a surface, from side to side.

    soil Noun

    top layer of the Earth's surface where plants can grow.

    solar energy Noun

    radiation from the sun.

    Encyclopedic Entry: solar energy
    solar radiation Noun

    light and heat from the sun.

    sparse Adjective

    scattered and few in number.

    stabilize Verb

    to anchor or make strong and reliable.

    steroid Noun

    type of organic compound that is often important to the functioning of an organism.

    subsistence agriculture Noun

    type of agriculture in which farmers grow crops or raise livestock for personal consumption, not sale.

    sustainable development Noun

    human construction, growth, and consumption that can be maintained with minimal damage to the natural environment.

    swamp Noun

    land permanently saturated with water and sometimes covered with it.

    Encyclopedic Entry: swamp
    temperate rain forest Noun

    wooded areas in cool, mild climate zones that receive high amounts of rainfall.

    temperature Noun

    degree of hotness or coldness measured by a thermometer with a numerical scale.

    Encyclopedic Entry: temperature
    terrestrial Adjective

    having to do with the Earth or dry land.

    textile Noun

    cloth or other woven fabric.

    thermostat Noun

    device used to establish and maintain a temperature.

    threatened species Noun

    organism that may soon become endangered.

    thrive Verb

    to develop and be successful.

    tide Noun

    rise and fall of the ocean's waters, caused by the gravitational pull of the moon and sun.

    Encyclopedic Entry: tide
    timber Noun

    wood in an unfinished form, either trees or logs.

    top predator Noun

    species at the top of the food chain, with no predators of its own. Also called an alpha predator or apex predator.

    toucan Noun

    large-billed bird native to South America.

    toxic Adjective

    poisonous.

    tract Noun

    area of land.

    trade Noun

    buying, selling, or exchanging of goods and services.

    traditional Adjective

    historic or established by custom.

    transpiration Noun

    evaporation of water from plants.

    tributary Noun

    stream that feeds, or flows, into a larger stream.

    Encyclopedic Entry: tributary
    tropical Adjective

    existing in the tropics, the latitudes between the Tropic of Cancer in the north and the Tropic of Capricorn in the south.

    tropical rain forest Noun

    grouping of tall evergreen trees, usually close to the Equator, which receives more than 203 centimeters (80 inches) of rain a year.

    tropics Plural Noun

    region generally located between the Tropic of Cancer (23 1/2 degrees north of the Equator) and the Tropic of Capricorn (23 1/2 degrees south of the Equator).

    Encyclopedic Entry: tropics
    tuber Noun

    thick part of an underground stem of a plant, such as a potato.

    understory Noun

    ecosystem between the canopy and floor of a forest.

    unique Adjective

    one of a kind.

    urban Adjective

    having to do with city life.

    vegetation Noun

    all the plant life of a specific place.

    virtually Adverb

    almost or nearly.

    vocalize Verb

    to say, sing, or otherwise make a vocal noise.

    vulnerable species Noun

    level of conservation between "near threatened" and "endangered." Vulnerable is the lowest of the "threatened" categories.

    waste Noun

    material that has been used and thrown away.

    water cycle Noun

    movement of water between atmosphere, land, and ocean.

    Encyclopedic Entry: water cycle
    wind Noun

    movement of air (from a high pressure zone to a low pressure zone) caused by the uneven heating of the Earth by the sun.

    zoning Noun

    system of sectioning areas within cities, towns, and villages for specific land-use purposes through local laws.

Funder

The Gordon and Betty Moore Foundation

Educational resources for this project funded by the Gordon and Betty Moore Foundation and the BIO Program at the Inter-American Development Bank.