Statement about Tropical Rainforests

Statement about Tropical Rainforests

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I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:

The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves

There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.

Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.

I looked for actual evidence of these differences in rates of decomposition and I found this:

Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977

These authors reported a comparison of rates of decomposition at various elevations in Peruvian forest. The parameter k is the decay rate of dry mass, year-1. The following data are taken from Table 3.

site elevation (m) mean k (yr-1; 15 species) Tambopata 210 1.753 Tono 1000 1.424 San Pedro 1500 0.968 Trocha Union 2720 0.546 Wayquecha 3025 0.424

and this:

Jacob, M. et al. (2010) Leaf litter decomposition in temperate deciduous forest stands with a decreasing fraction of beech (Fagus sylvatica) Oecologia 164:1083-1094

These authors studied leaf decomposition in a deciduous forest in Germany, with emphasis on the effect of proportion of beech trees upon overall rates of decomposition. Using data from Table 1 and Figure 2 (values converted from mg-1 g-1 day-1 to yr-1)

% beech yr-1 96 0.2555 67 0.657 21 1.022

My Conclusion

Rates of decomposition can be much higher in tropical rainforest (k=1.753 yr-1 for the Tambopata site in Peru, k=0.256 yr-1 for a beech-rich forest in Germany). However, at higher elevations tropical rain forests are characterised by much lower rates of decomposition (Wayquecha k=0.424 yr-1), comparable to those in deciduous forests.

These are all measurements of loss of dry mass from leaf litter. This will be dominated by loss of carbon, and I would expect that minerals will leach from the decaying litter more rapidly than these values. Nevertheless it seems plausible that relative rates of mineral recycling will reflect these k values.

Tropical rain forest evolution: palms as a model group

The biological diversity and complexity of tropical rain forests have fascinated biologists for centuries. This, the most species-rich terrestrial biome on Earth, is now severely threatened by human activity and yet we are still far from answering fundamental questions about its origins and evolution. Where and how did this huge diversity originate? What evolutionary processes were involved? How can we explain the patterns of current biodiversity across this biome?

Basic biodiversity data, such as species composition, distribution and phylogenetic relationships, are fundamental prerequisites for a better understanding of tropical rain forest evolution. Species inventories, for example, can be exploited to unpick the evolutionary history of tropical rain forest assemblages using community phylogenetic approaches [1]. Perpendicular to this approach, taxonomic and systematic research focusing on lineages predominantly restricted to tropical rain forests can be rewarding [2]. In particular, dated phylogenies of tropical rain forest lineages can be used to unravel the evolutionary origins, timescales and processes of this biome as a whole. In this comment, we describe how one such tropical rain forest-restricted lineage, the palm family, has provided evidence of global rain forest history in a succession of recent studies integrating a range of basic biodiversity datasets [3–9], the first of which was published in BMC Biology [3], and now represents a model for the study of the tropical rain forest biome that may, potentially, be applied to other lineages of organisms.

Tropical Rainforest Biome

The first thing you’ll notice when you visit a tropical rainforest is the abundance of plants, both in shear biomass and total biodiversity. Plants thrive when the yearly average temperature and precipitation, in the form of tropical rains, is high. Below, we describe their main characteristics, where they’re found, the layers of the forest and some common animals you might see on a visit to this biome.

Characteristics of the Tropical Rainforest Biome

All biomes are characterized by the dominant vegetation. In the rainforest biome there are tall trees and warm temperatures all year. The yearly average rainfall is from 50 to 260 inches. The temperature is warm but not hot. Almost every rainforest you might visit has a temperature range of 93°F to 69°F. The average humidity is between 77 and 88 percent.

Where are Rainforests Found?

Tropical Rainforests are found in a tropical belt around the equator where annual temperature and precipitation are high. However, rainforests now cover much less of Earth’s surface than they once did.

Biodiversity of Rainforests?

Today, about 6 percent of the surface of Earth is covered in rainforests, and more than half of all the world’s plant and animal species live in them. The shear biomass of plants in the rainforest help produce about 40 percent of Earth’s oxygen.

Estimates of the Earth’s biodiversity originally came from studies in Panama, where tree species were logged and the number of insects within them categorized and counted. Estimates range from 10 to 100 million species on earth, most of them being insects found in the tropical rain forests.

The tropical rainforests have more kinds of trees than any other biome in the world. In a rainforest in South America, scientists counted from 100 to 300 species of tree in 2.5 acre sections of the forest. Not all plants in the rainforest are trees though. While they are the easiest to observe, there is a great diversity of epiphytes, plants that live on other plants, that make the rainforest their home. Plants like orchids live on rainforest trees high in the canopy.

It has been estimated that about 25 percent of the medicines we use come from plants in the rainforest, such as:

  • Curare, a tropical vine, is used as an anesthetic and muscle relaxant during surgery.
  • Quinine from the cinchona tree is taken to treat malaria.
  • Rosy Periwinkle from Madagascar is used to treat lymphocytic leukemia.

The look of a typical rainforest

All tropical rain forests resemble one another in some ways. Many of the trees have straight trunks that don’t branch out for 100 feet or more there is no sense in growing branches below the canopy where there is little light. The majority of the trees have smooth, thin bark because there is no need to protect the them from water loss and freezing temperatures. It also makes it difficult for epiphytes and plant parasites to get a hold on the trunks. The bark of different species is so similar that it is difficult to identify a tree by its bark. Many trees can only be identified by their flowers.

Despite these differences, each of the three largest rainforests–the American, the African, and the Asian–has a different group of animal and plant species. Each rainforest has many species of monkeys, all of which differ from the species of the other two. In addition, different areas of the same rainforest may have different species. Many kinds of trees that grow in the mountains of the Amazon rainforest do not grow in the lowlands of that same forest.

Visiting The Tropical Rainforests

There is no one place to visit if your destination is tropical rainforests. The crew of Untamed Science particularly like the rainforests of Central and South America, but we have many other favorites as well. We spent nearly 9 months in Panama shooting videos and staying at the Smithsonian Tropical Research facility, Barro Colorado Island (BCI). The following video is a short glimpse into what BCI is like.

Speech on the rain forest

Attention Getter: The rainforest is one of the Earth’s most valuable natural resources. At the current rate of destruction it could be completely wiped out in the next 40 years.

Audience Motivator: Every single day we are losing 137 plants, animal and insect species due to rainforest deforestation (Rainforest Facts). Landowners and governments of the rainforest today need to be given a good economic reason not to destroy the rainforest. We need to make an economy for the sustainable resources of the rainforest, not the cattle and logging operations.

Thesis Statement: Most people have no idea just how much the rainforest is affecting our lives. Many of our foods and medicines come directly from the rainforest. Even the oxygen we breathe is a direct function of the rainforest. If we let the rainforest disappear, the results would be devastating.

Preview: I am going to let you in on some information that everyone should know about the rainforest. I am going to tell you about the serious danger that the rainforest is in and tell you why it is happening.

“ Really polite, and a great writer! Task done as described and better, responded to all my questions promptly too! ”

Transition Statement: You will here me tell you about some very interesting and important facts. It is important to understand how much each and every one of us really does need the rainforest.

A.What makes up the rainforest

Rainforests cover 2% of the Earth’s surface, or 6% of its land mass. Tropical rainforests are the earth’s oldest living ecosystem. Fossil records show that the forests of Southeast Asia have existed in more or less their present form for 70 to 100 million years.

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Tropical rainforests are defined by two factors: location and amount of rainfall they receive.

B.The important of the rainforest

1.Amount of rainfall the rain forest receives

Rainforests receive 4 to 8 meters of rain a year and 5 meters of rain falls on the rainforests of Borneo each year which is five times as much as on the state of New York.

2.Rainforests are home to plants and animals

Despite the land area they cover, rainforest are the home to about half of the 5 to 10 million plants and animal species on the globe. Rainforests also support 90,000 of the 250,000 identified plant species. Scientists estimate that there are at least 30,000 as yet undiscovered plants, most of which are rainforest species. A typical four square mile patch of rainforest contains as many as 1500 species of flowering plants, 750 species of trees, 125 mammal species, 400 species of birds, 100 of reptiles, 60 of amphibians, and 150 different species of butterflies.

Transition Statement: Hopefully you can now see that the rainforest is in fact important to us. Unfortunately, it is in serious danger.

Second Main Point: The problem: Deforestation and Species Extinction

Rainforests are being destroyed at a staggering rate. According to the National Acadmey of Science, at least 50 million acres a year are lost, an area the size of England, Wales, and Scotland combined. Rainforests which once covered 14% of earth’s surface, now 6%. 1-? acres are lost every second.

Nearly half of the world’s species of plants and animals will be destroyed or severely threatened over the next 25 years due to deforestation. If deforestation continues at current rates, scientists estimate that 80-90% of tropical RF ecosystems will be destroyed by 2020. This is driving a species extinction rate unmatched in 65 million yrs (The Biodiversity). The biggest cause of deforestation is timber logging. Land is also being cleared for large-scale cattle ranching, mining operation, government road building and hydroelectric schemes, military operations, and subsistence agriculture of peasants and landless settlers. In some places even for charcoal to power industrial plants (Human Activities). Massive deforestation brings with it air and water pollution, soil erosion, malaria epidemic, release of carbon dioxide, loss of biodiversity. Less RF means less rain, oxygen, and greater threat of global warming.

One fourth of the medicines available today owe their existence to plants. 70% of the plants found only in the rainforest are used for cancer treatment, such as drugs to treat leukemia, hodgkin’s disease, and other cancers. Yet, fewer than 1% of tropical species have been thoroughly examined for their chemical compounds.

Many of the foods we eat today originated in the rainforests: avocado, banana, black pepper, brazilian nuts, cayenne pepper, chocolate/cocoa, fig, eggplant, etc. The wild strains still in the rainforests of many of these plants provide genetic materials essential to fortify our existing agricultural stock. Many other rainforests plants have great promise to become other staple foods.

Rainforests play a critical role in the atmosphere in part because they hold vast reserves of carbon in their vegetation. When rainforests are burned, or the trees are cut and left to decay, the carbon is released into the atmosphere as carbon dioxide. This is the second largest factor contributing to the greenhouse ffect.

Transition Statement: The rainforests are being destroyed every second. They are being cut down for short-term economic benefit. Once an area is destroyed, it can never again return to the amazing ecosystem that it once was. It takes millions of years to create, and seconds to destroy. People who live in the rainforest have to see the rainforest for more than just its trees. There is more money to be made in the sustainable natural resources that it holds, than its timber.

Third Main Point: Money makes the world go around. Land owners, governments and those living in the RF must be given a wonderful reason not to destroy the RF, when it could be saved. Many organizations have demonstrated that if the medicinal plants, fruits, nuts, oils and other resources were harvested sustainable, RF land has much more economic value today and more long term income and profits than if just timber were harvested or if it were burned down for cattle or farming operations(Going Nuts).

Reduce your own wood and paper use. Use both sides of each piece of paper, use cloth napkins instead of paper towels, avoid disposable paper plates and cups. When purchasing paper products, choose products with the highest percentage of recycled content. Choose tree-free paper alternatives if possible, that is argricultural products like waste straw, kenaf, and hemp, so not a single tree is cut down for its production! Reduce oil and gas consumption. Buy a car that gets good gas mileage, car pool, local transportation, or walk.

Thesis Statement: After telling you about what is necessary to save the rainforest, I hope that everyone will seriously consider becoming a part of the demand for sustainable natural resources.

Main Point Summary: I have told you why we should all love and appreciate the rainforest. I have told you the serious danger that the rainforest is facing, and finally told you the solution that can fix it.

Closing Statement: There is a way to save the rainforest. It won’t be easy, and it won’t happen overnight. We have to work together if we want to save this precious natural resource. Every 6-8 minutes 540-720 acres of rainforest has been lost forever.

General structure of the rainforest

Plants with similar stature and life-form can be grouped into categories called synusiae, which make up distinct layers of vegetation. In tropical rainforests the synusiae are more numerous than in other ecosystem types. They include not only mechanically independent forms, whose stems are self-supporting, and saprophytic plants but also mechanically dependent synusiae such as climbers, stranglers, epiphytes, and parasitic plants. An unusual mix of trees of different sizes is found in the tropical rainforest, and those trees form several canopies below the uppermost layer, although they are not always recognizably separate layers. The upper canopy of the tropical rainforest is typically greater than 40 metres above ground.

The tropical rainforest is structurally very complex. Its varied vegetation illustrates the intense competition for light that goes on in this environment in which other climatic factors are not limiting at any time of year and the vegetation is thus allowed to achieve an unequaled luxuriance and biomass. The amount of sunlight filtering through the many layers of foliage in a tropical rainforest is small only about 1 percent of the light received at the top of the canopy reaches the ground. Most plants depend on light for their energy requirements, converting it into chemical energy in the form of carbohydrates by the process of photosynthesis in their chlorophyll-containing green tissues. Few plants can persist in the gloomy environment at ground level, and the surface is marked by a layer of rapidly decomposing dead leaves rather than of small herbaceous plants. Mosses grow on tree butts, and there are a few forbs such as ferns and gingers, but generally the ground is bare of living plants, and even shrubs are rare. However, tree seedlings and saplings are abundant their straight stems reach toward the light but receive too little energy to grow tall enough before food reserves from their seeds are exhausted. Their chance to grow into maturity comes only if overhanging vegetation is at least partially removed through tree death or damage by wind. Such an occurrence permits more solar radiation to reach their level and initiates rapid growth and competition between saplings as to which will become a part of the well-lit canopy.

Gaps in the canopy of a tropical rainforest provide temporarily well-illuminated places at ground level and are vital to the regeneration of most of the forest’s constituent plants. Few plants in the forest can successfully regenerate in the deep shade of an unbroken canopy many tree species are represented there only as a population of slender, slow-growing seedlings or saplings that have no chance of growing to the well-lit canopy unless a gap forms. Other species are present, invisibly, as dormant seeds in the soil. When a gap is created, seedlings and saplings accelerate their growth in the increased light and are joined by new seedlings sprouting from seeds stored in the soil that have been stimulated to germinate by light or by temperature fluctuations resulting from the sun’s shining directly on the soil surface. Other seeds arrive by various seed-dispersal processes (see below). A thicket of regrowth rapidly develops, with the fastest-growing shrubs and trees quickly shading out opportunistic, light-demanding, low-growing herbaceous plants and becoming festooned with lianas. Through it all slower-growing, more shade-tolerant but longer-lived trees eventually emerge and restore the full forest canopy. The trees that initially fill in the gap in the canopy live approximately one century, whereas the slower-growing trees that ultimately replace them may live for 200 to 500 years or, in extreme cases, even longer. Detailed mapping of the trees in a tropical rainforest can reveal the locations of previous gaps through identification of clumps of the quicker-growing, more light-demanding species, which have yet to be replaced by trees in the final stage of successional recovery. Local, natural disturbances of this sort are vital to the maintenance of the full biotic diversity of the tropical rainforest (see Sidebar: Rainforest Regeneration in Panama).

Just as tropical rainforest plants compete intensely for light above ground, below ground they vie for mineral nutrients. The process of decomposition of dead materials is of crucial importance to the continued health of the forest because plants depend on rapid recycling of mineral nutrients. Bacteria and fungi are primarily responsible for this process. Some saprophytic flowering plants that occur in tropical rainforests rely on decomposing material for their energy requirements and in the process use and later release minerals. Some animals are important in the decomposition process for example, in Malaysia termites have been shown to be responsible for the decomposition of as much as 16 percent of all litter, particularly wood. Most trees in the tropical rainforest form symbiotic mycorrhizal associations with fungi that grow in intimate contact with their roots the fungi obtain energy from the tree and in turn provide the tree with phosphorus and other nutrients, which they absorb from the soil very efficiently. A mat of plant roots explores the humus beneath the rapidly decomposing surface layer of dead leaves and twigs, and even rotting logs are invaded by roots from below. Because nutrients are typically scarce at depth but, along with moisture, are readily available in surface layers, few roots penetrate very deeply into the soil. This shallow rooting pattern increases the likelihood of tree falls during storms, despite the support that many trees receive from flangelike plank buttresses growing radially outward from their trunk bases. When large trees fall, they may take with them other trees against which they collapse or to which they are tied by a web of lianas and thereby create gaps in the canopy.

Tree growth requires substantial energy investment in trunk development, which some plants avoid by depending on the stems of other plants for support. Perhaps the most obvious adaptation of this sort is seen in plants that climb from the ground to the uppermost canopy along other plants by using devices that resemble grapnel-like hooks. Lianas are climbers that are abundant and diverse in tropical rainforests they are massive woody plants whose mature stems often loop through hundreds of metres of forest, sending shoots into new tree crowns as successive supporting trees die and decay. Climbing palms or rattans ( Calamus) are prominent lianas in Asian rainforests, where the stems, which are used to make cane furniture, provide a valuable economic resource.

Epiphytes are particularly diverse and include large plants such as orchids, aroids, bromeliads, and ferns in addition to smaller plants such as algae, mosses, and lichens. In tropical rainforests epiphytes are often so abundant that their weight fells trees. Epiphytes that grow near the upper canopy of the forest have access to bright sunlight but must survive without root contact with the soil. They depend on rain washing over them to provide water and mineral nutrients. During periods of drought, epiphytes undergo stress as water stored within their tissues becomes depleted. The diversity of epiphytes in tropical deciduous forests is much less than that of tropical rainforests because of the annual dry season (see Sidebar: Life in a Bromeliad Pool).

Parasitic flowering plants also occur. Hemiparasitic mistletoes attached to tree branches extract water and minerals from their hosts but carry out their own photosynthesis. Plants that are completely parasitic also are found in tropical rainforests. Rafflesia, in Southeast Asia, parasitizes the roots of certain lianas and produces no aboveground parts until it flowers its large orange and yellow blooms, nearly one metre in diameter, are the largest flowers of any plant.

Stranglers make up a type of synusia virtually restricted to tropical rainforests. In this group are strangler figs (Ficus), which begin life as epiphytes, growing from seeds left on high tree branches by birds or fruit bats. As they grow, they develop long roots that descend along the trunk of the host tree, eventually reaching the ground and entering the soil. Several roots usually do this, and they become grafted together as they crisscross each other to form a lattice, ultimately creating a nearly complete sheath around the trunk. The host tree’s canopy becomes shaded by the thick fig foliage, its trunk constricted by the surrounding root sheath and its own root system forced to compete with that of the strangling fig. The host tree is also much older than the strangler and eventually dies and rots away, leaving a giant fig “tree” whose apparent “trunk” is actually a cylinder of roots, full of large hollows that provide shelter and breeding sites for bats, birds, and other animals (see Sidebar: Apartments of the Rainforest). Stranglers may also develop roots from their branches, which, when they touch the ground, grow into the soil, thicken, and become additional “trunks.” In this way stranglers grow outward to become large patches of fig forest that consist of a single plant with many interconnected trunks.

Animals That Live In Tropical Rainforests

Rainforests are extremely biodiverse habitats – which basically means that a large number of species live in them.

South American tropical rainforests are home to animals such as caimans, jaguars, green anacondas, boa constrictors, harpy eagles, red-eyed tree frogs and howler monkeys.

In African tropical rainforests you’ll find leopards, African forest elephants, gorillas, chimpanzees, okapis, parrots and hornbills.

Animals that are found in Asian tropical rainforests include orangutans, tigers, Asian elephants, crocodiles, dholes, clouded leopards, sun bears, gibbons, Malaysian tapirs and slow lorises.

Australian tropical rainforests are home to tree kangaroos, parrots, saltwater crocodiles, cassowaries, Australian brush turkeys, Cairns bird wing butterflies and goannas.

As you can see, tropical rainforests are home to many varied animal species, and we’re only just scratching the surface. No other habitat on Earth is home to as many different species.

  • You’ll find an illustrated list that includes many of the most amazing rainforest animals here: Rainforest Animals.

Protecting Biodiversity in the Amazon Rainforest

Students explore biodiversity in the Amazon rainforest using the MapMaker Interactive and other online resources. Then students construct an argument for protecting biodiversity in the Amazon rainforest.

Biology, Geography, Human Geography



1. Activate students’ prior knowledge about the environmental effects of biodiversity loss.

Activate students’ prior understanding about human impacts on the environment by showing a photograph of clear-cutting in Brazil. Define the vocabulary terms clear-cutting and deforestation and then read aloud the photo caption. Have students discuss what the photo shows and brainstorm potential consequences to the ecosystem. Ask: What did this area look like before clear-cutting happened? What organisms might live in an area like this? What are some reasons people cut down trees in a rainforest? Who benefits from cutting down the trees? If possible, elicit local examples of forest or biodiversity loss (e.g., for new development) to illustrate the fact that this is also happening locally, not just in faraway countries. Have students answer the same questions for the local example. Ask: What living things are affected by clearing areas for development? How are they affected? Then have students return to thinking about the effects of deforestation on the Amazon rainforest ecosystem and answer the same questions. Ask: What living things are affected by deforestation? How are they affected? Invite volunteers to share their thinking with the class. The focus of this discussion is to get students thinking about what organisms inhabit the tropical rainforest and how habitat destruction affects where they live, how they live, and possibly the survival of their species. Introduce the term biodiversity and explain that the Amazon rainforest is the most biodiverse place on Earth. But, this biodiversity is threatened due to human activity. Explain to students that they will explore biodiversity in the Amazon to try to understand why it is so important to protect. Tell students that the purpose of this activity is for them to construct an argument for protecting biodiversity of the Amazon rainforest.  

2. Construct knowledge about biodiversity in the Amazon rainforest.

Project the MapMaker Interactive geo-tour Geography and Wildlife of the Amazon Basin on a screen and select the bookmark Where is the Amazon Basin? Point out the highlighted Amazon Basin and discuss its location and size. During this time, if students are unfamiliar with the MapMaker Interactive, point out some of the basic tools like zooming in (+) and out (-). Also point out the bookmarks at the bottom of the map. Explain to students that they will work in small groups to learn more about a smaller region of the Amazon rainforest. Distribute the worksheet Exploring the Animals and Plants in the Amazon Rainforest. Divide students into small groups of three to explore different regions (north, west, east) of the Amazon rainforest. Assign a different region to each group. More than one group will investigate the same region. Explain that while the Amazon rainforest is known for its biodiversity, in this activity students will investigate a very small sample of the vast biodiversity that exists in this region. Have each student complete Part 1. Using MapMaker to Explore Animals and Plants in Regions of the Amazon Rainforest. Direct them to select three animals and three plants from their assigned region and write facts relevant to the importance of the plant and animal within the habitat. Advise students to focus on how the plants and animals interact with other organisms in the forest as they complete the tables. Explain to students that this information will provide the evidence they need to support the arguments they will construct later in the activity.

3. Extend students’ understanding of biodiversity through online research.

Once students have completed Part 1 of the worksheet, have them select one animal and one plant to research further online and complete Part 2. Conducting Online Research. Direct students to use website links associated with each plant or animal in the Geography and Wildlife of the Amazon Basin geo-tour. Ask students to add the facts they find to their tables on the worksheet.

4. Introduce threats to the Amazon rainforest.

Have students recall the clear-cutting photograph in Brazil from the beginning of the activity and share some of the real-world threats to the rainforest: human development, deforestation due to logging and cattle ranching, infrastructure development, hydroelectric power projects, and others. Focusing on their region (from step 3 above), ask students to consider the consequences of habitat destruction to the plants and animals from their region and discuss this in their groups. Ask students to take notes that could be useful when constructing their arguments about protecting the biodiversity of the Amazon rainforest.

5. Construct an evidence-based argument for protecting biodiversity in the Amazon rainforest.

Distribute the rubric Evidence-Based Argument about Protecting Biodiversity in the Amazon Rainforest and review it with students. Next, distribute the worksheet Constructing an Evidence-Based Argument. Ask students to construct their evidence-based argument for why it is important to protect biodiversity in the Amazon rainforest. Introduce and explain the components of a scientific argument:

  • Claim: a statement that answers the original question/problem.
  • Evidence: scientific data that supports the claim. The data needs to be appropriate and sufficient to support the claim.
  • Reasoning: a justification that connects the evidence to the claim. 

Remind students that the facts they collected from their exploration of the Geography and Wildlife of the Amazon Basin geo-tour in the MapMaker Interactive and from their online research will serve as the evidence they need to support their claims.

6. Have students present their scientific arguments.

Have students share their arguments about the importance of protecting biodiversity in the Amazon rainforest with the class. Students with the same region should present following each other so students can compare the different pieces of evidence and reasoning they used to support their claim. Conclude with a whole-class discussion reflecting on the potential loss of biodiversity in the Amazon rainforest. Ask: What is biodiversity? What is important about biodiversity in the Amazon rainforest? What happens when biodiversity decreases? What environmental issues are impacting biodiversity?

Alternative Assessment

Use the provided answer key for the worksheet Exploring the Animals and Plants in the Amazon Rain Forest and the provided rubric to score each group&rsquos scientific arguments.

Five myths about tropical rainforests

Thousands of fires are burning in the Amazon, eliciting panic around the world and offers of help from the Group of Seven meeting last weekend. Tropical rainforests cover only 2 percent of the Earth’s surface, but they have an outsize impact on providing habitat, storing carbon and regulating the flow of water. From the “Save the Rainforest” T-shirts of the 1990s to the sci-fi movie “Avatar,” these areas have come to symbolize the abundance of the natural world — and its vulnerability. But misconceptions about rainforests abound.

Logging companies

Drive deforestation.

Calling logging “perhaps the most iconic symbol of forest destruction,” the Union of Concerned Scientists lists “wood products” among its top four causes of deforestation. HowStuffWorks also claims that logging is a “primary driver” of the problem. This myth has worked its way into popular culture: The animated film “FernGully: The Last Rainforest,” from 1992, depicted a logging operation as the main existential threat to the forest’s adorable creatures. And it’s true that logging wreaks havoc on the rainforest: Often conducted illegally, it creates significant carbon emissions and reduces species richness. It can also lead to future deforestation by building roads that increase access to remote areas.

But logging is currently responsible for less than 10 percent of deforestation in the world’s largest tropical rainforests, according to a recent study in the journal Science. With deforestation, a forest is completely cut down and converted to another use, which normally doesn’t happen when loggers selectively remove valuable trees.

Agriculture accounts for 80 percent of deforestation in the tropics, with a large portion tied to just three commodities: palm oil, soybeans and beef. These are often traded internationally and show up in everyday products like toothpaste, shampoo, dog food and granola bars.

The Amazon rainforest functions as the Earth's 'lungs.'

French President Emmanuel Macron tweeted that “the Amazon rain forest — the lungs which produces 20% of our planet’s oxygen — is on fire,” a claim repeated by the likes of actor Leonardo DiCaprio and soccer star Cristiano Ronaldo. The phrase has also popped up throughout the reporting on the fires in the Amazon, including on CNN, ABC and Al Jazeera.

Though trees do produce oxygen, they also consume it during cellular respiration. From there, microbes and other organisms use much of the oxygen generated by rainforests, resulting in a net production of oxygen close to zero. “There are a number of reasons why you would want to keep the Amazon in place, oxygen just isn’t any one of them,” Michael Coe, a scientist at the Woods Hole Research Center in Massachusetts, told National Geographic. In fact, according to the National Oceanic and Atmospheric Administration, seasonal phytoplankton blooms are responsible for more than half of atmospheric oxygen production on Earth.

Still, rainforests across Latin America, Africa and Southeast Asia store about a quarter of the world’s carbon, and their deforestation accounts for more than 15 percent of gross human-caused greenhouse gas emissions worldwide each year. They also influence how the atmosphere functions. For example, the water vapor that tropical forests release into the air results in increased rainfall up to hundreds of miles away.

The rainforest is uninhabited wilderness.

Advertisements for tourist excursions often refer to tropical rainforests as “virgin” and “untouched.” To many, these places exemplify wilderness — paradises untrammeled by human intervention and thus teeming with plant and animal life. This misconception has had tragic consequences for local and indigenous people. According to a U.N. report from 2018, countries including Peru, Panama and Indonesia have forced communities from their traditional lands to create protected areas of “pristine” nature.

In truth, these areas are not naturally uninhabited. People have lived in tropical rainforests for thousands of years and continue to occupy large areas within them: Indigenous territories cover 35 percent of the Amazon, for example. Local communities have made a profound impact on the forests’ structure across time. Recent archaeological and ecological studies suggest that pre-Columbian peoples changed the plant composition of the Amazonian rainforest by domesticating and cultivating species such as the Brazil nut.

Deforestation rates inside indigenous territories are two to three times lower than in surrounding areas, according to the World Resources Institute (where I lead strategy and partnerships for satellite-based forest monitoring at Global Forest Watch). These territories do an even better job of protecting tropical forests than areas that strictly prohibit human activities. Securing land titles for indigenous territories may be one of the most cost-effective ways to mitigate carbon emissions.

Tropical rainforests are doomed.

It’s hard not to be alarmed reading the headlines about tropical rainforests. As early as 2009, the Independent said that the “f ate of the rainforest is ‘irreversible.’ ” “We are destroying rainforests so quickly they may be gone in 100 years,” the Guardian said in 2017. The Economist says that the Amazon is on “deathwatch. ” Last year the world lost 3.6 million hectares of primary rainforest, an area the size of Belgium.

But some countries have managed to significantly slow deforestation. Global Forest Watch reported a 40 percent decline in Indonesia’s forest loss in 2018 compared with its 2002-2016 average, thanks in part to the government’s response to the massive fires in 2015. Before its recent policy reversals, Brazil actually reduced large-scale deforestation in the Amazon by 70 percent between 2004 and 2012.

We know how to stop deforestation — by increasing law enforcement efforts, establishing protected areas, recognizing indigenous territories, regulating agricultural conversion and paying landowners for environmental services. If Indonesia and Brazil, historically the worst deforesters, are capable of turning things around, there’s hope for rainforests as a whole. For that to happen, though, tropical forest countries and the countries that consume deforestation-linked commodities will all need to significantly shift their policies and practices.

We need to clear rainforest to feed the world.

With the global population expected to rise to more than 9 billion by mid-century, the World Resources Institute says the global food supply will need to increase by more than 50 percent. In recent decades, most new farmland has come from cutting down tropical rainforest. An article in Fast Company, warning that “there won’t be enough food to feed the world in 2050,” says that “growers will probably resort to clear-cutting more forests.” Brazil’s chief of strategic affairs, Maynard Santa Rosa, recently called the Amazon “an unproductive latifúndio” — a big, unfarmed estate — that needed to be developed for agriculture, mining and logging. According to Wired, “Farmers in Brazil are starting these fires not because of some vendetta against the rainforest, but because they need to feed their families.”

But it’s entirely possible to feed billions of additional people without expanding agriculture into forests. Boosting crop and livestock productivity can help the world produce more food on existing farmland: In Latin America, for example, some farmers are planting improved grasses on pasturelands, or even adding trees this helps the land grow more and better feed, and increases the number of cows per acre. The world can also alter its consumption patterns by reducing the approximately one-third of food that’s wasted and by shifting toward plant-based foods, which are less land-intensive than animal-based foods.

In fact, preserving the rainforests may be necessary to meet demand for food. Tropical rainforests regulate local climate by providing shade and returning water vapor to the atmosphere, humidifying and cooling the air they also provide valuable pollination services to nearby fields. Clearing those forests changes the volume and distribution of rainfall and leads to drier and hotter conditions, which has negative effects on agricultural yields. For example, a study in Environmental Research Letters found that deforestation in the Amazon may decrease the productivity of pastures (because of decreased rainfall in eastern Brazil) and soybean farms (because more days have temperatures above the optimum range).

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Repurposing the Camera Trap

She first considered tracking individual monkeys using radio collars to see if they would use the bridges, but ultimately ruled that out. Using radio collars to track animals is a common practice, but catching and collaring monkeys would not be easy. Researchers would first need to locate the monkeys in the canopy and then dart them to safely attach the collars. If that was successful, the data would still only reveal the use of the bridges by those few monkeys. Gregory wanted a full picture of how many different animals would use them to cross a pipeline clearing.

Show Offs

Though relationships between different species in the rainforest can be interesting, the most amazing things you see in the rainforest are sometimes between a male and female of the same animal species. When some animals are looking to reproduce, or have babies, they need to attract another animal with which they can mate. Oftentimes, in species that have sexual reproduction, it is the male that tries to attract a female.

Male cock-of-the-rocks' bright colors are difficult for females, or anyone else, to miss. Image by Marie de Carne.

Some males attract females with amazing dances or colors, using tricks to try to show off for, or impress, a female. The cock-of-the-rock, a type of bird that lives in the undergrowth of the forest, has males with bright red and black color patterns. Five to 20 of these bright males fly, dance and call together in a group called a lek. These birds dance in a small area to try to attract one of the dull-colored females.

When a female arrives at the dancing grounds, the males dance and call even harder. Even with up to 20 males calling, only one male wins out—usually the brightest, the loudest, or the best dancer.

With all the different bright display colors of some animals, the dark, shadowy, green rainforest can be transformed into a beautiful show of moving colors.

Watch the video: Φοινικέλαιο: Ένα λάδι που καίει τα τροπικά δάση (August 2022).