A STUDYGUIDE bY Andrew Fildes

8 www.metromagazine.com.au

www.theeducationshop.com.au

Overview Planet Earth is a BBC production with five episodes in the first series (episodes one through five) and six episodes in the second series (episodes six through eleven). Each episode examines a specific environment, focussing on key species or relationships in each habitat; the challenges they face; the behaviours they exhibit and the adaptations that enable them to survive. Recent advances in photography are used to achieve some spectacular ‘first sights’ – in particular, stabilised aerial photography gives us remarkable views of migrating animals and the techniques used by their predators to hunt them. As the series examines pristine environments where possible, they are often extreme. These are the parts of the world where few humans have chosen to live as the climate and landscape is too challenging, too difficult and dangerous. The plants and animals that do survive here have made some spectacular adaptations in forms and behaviour to live in these far reaches of the planet. The series is suitable for middle secondary students studying Science and SOSE, and for senior secondary students of Biology, Environmental Science and Geography.

SCREEN EDUCATION



1 Episode Eight: Jungles Jungles, or rainforests as we tend to call them in Australia, are one of the most unusual, special and precious ecosystems on the planet. They are not pleasant places for people to live, being rich in wild foods but also poor in soil, rich in insects that bite, predatory fungi and trees that sting. Traditionally the main threat has been from those in search of their precious, high quality timbers and others who mistakenly assume that such a rich ecosystem must be powered by a rich, fertile soil. The opposite is the case but still, every year, huge areas of the Amazon forest are cleared for grazing cattle, raised to supply the developed world with coffee and burgers. These forests are so huge that they can create their own climate and may have a significant contribution to the global climate, far beyond their own border. The jungle environment was seen as worthless except for what resources it could provide us. Despite the fact that the big rainforests like the Amazon and the Congo cover huge areas, others are now reduced to tiny, threatened pockets in desperate need of protection.

The unique nutrient recycling system is examined, showing how the richest ecosystem on earth can be supported by the poorest soils. The role of fungi in decomposing the forest floor leaf litter directly back to the tree roots is critical and still poorly understood. In those lower levels many of the animals are invertebrates, perhaps eighty per cent of the world’s insects live here. Strangely, their greatest predators

are not other animals but aggressive fungi that infect and infest their bodies – there is unique time lapse photography of the grim fate of many insects. Africa’s Congo forests are large and deep enough to hide large animals such as small families of forest elephants who must seek out special ways of living in a nutrient poor environment with many toxic plants, sucking up rare medicinal muds from pools in clearings to counteract the effects of their lifestyle. Finally, we are introduced to a large tribe of rainforest chimpanzees, our close relatives and the comparison is unsettling to say the least. Their behaviour is both very social and very intolerant of their neighbours, a chilling comment perhaps on our own nature.

Episode 8: Jungles

Time Log

Intro and Birds of Paradise

00:00 - 4:30

Rainforest Regeneration

04:30 - 10:00

The Fig Tree Food Source

10:00 - 13:45

Territorial Monkeys

13:45 - 16:10

Singing Insects

16:10 - 17:08

Tree Frogs

17:08 - 21:24

Rainforest Climate

21:24 - 23:20

Slime Moulds and Fungi

23:20 - 27:00

Predatory Fungi

27:00 - 30:00

Colugo (arboreal mammal)

30:00 - 31:55

Carnivorous Pitcher Plant

31:55 - 35:25

Congo Clearing and Elephants

35:25 - 41:00

Chimpanzee Tribe

41:00 - end

(Timings are approximate)

SCREEN EDUCATION

In this episode we see the hidden life of an environment we rarely enter beginning with the displays of the birds of paradise in the deep jungles of New Guinea. Many of these birds were only discovered when their remarkable plumes were seen on the ceremonial outfits of highland tribesmen who were using them in much the same way as the birds, for ritual public display. We are introduced to an environment where the ground level is permanently dark and to the plants and animals

that can take advantage of the gloom and damp at the base of the giant trees. This is a habitat that always has food for its inhabitants as there are no real seasons so the creatures that live there concentrate on defending their territories. An environment so humid that frogs can live out of the water and in the high trees.



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Web Resources http://www.bbc.co.uk/nature/ programmes/tv/jungle/vjstructure. shtml http://en.wikipedia.org/wiki/ Deforestation http://rainforest-australia.com/forest. htm (Forest floor activity)

Species List

lidryas Slime Moulds – Myxomycota spp. Bullet Ants – Paraponera clavata Parasitic Insect Fungi – Cordyceps spp. Colugo (Gliding Lemur) – Cynocephalus variegatus Pitcher Plant – Nepenthes gracilis Red Crab Spider – Misumenops nepenthicola African Forest Elephant – Loxodonta cyclotis Red River Hog – Potamochoerus porcus Bongo – Tragelaphus eurycerus Common Chimpanzee – Pan troglodytes

SCREEN EDUCATION

Blue Bird of Paradise – Paradiseaea rudophi Magnificent Riflebird – Ptiloris magnificus Lawes’s Parotia – Parotia lawesii

Magnificent Bird of Paradise – Cicinnurus magnificus Fig Tree – Ficus spp. Red-faced Spider Monkey – Ateles paniscus Emperor Tamarin – Saguinus imperator Common Squirrel Monkey – Saimiri sciureus White-fronted Capuchin Monkey – Cebus albifrons Venezuelan Red Howler Monkey – Alouatta seniculus Siamang Gibbon – Symphalangus syndactylus Bornean Orangutan – Pongo pygmaeus Red-eyed Tree Frog – Agalychnis cal-



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Blackline Master | Planet Earth | Episode 8: Jungles Viewing Questions

SCREEN EDUCATION



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1 What proportion of the earth’s surface is jungle/rainforest?

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2 What proportion of the earth’s plant and animal species

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8 What type of animals seek out the fruits?

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3 What percentage of sunlight reaches the ground?

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9 Where in the forest do the frogs live?

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4 Why does the bird of paradise dance and sing?

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10 What attracts the female frog most in a male?

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5 How many species of tree can be found in a hectare of

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6 Which plants respond fastest to the available light?­

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12 What do the slime moulds feed on?

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7 Which is the most important food tree of the rainforest?

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SCREEN EDUCATION

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13 What other organisms feed on the same materials?

19 Why does the pitcher plant have to eat insects?

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14 Why is the soil in a jungle so poor?

20 How can the crab spider survive in the pitcher plant?

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15 Why are the fungi essential to the tree’s survival?

21 What do the elephants need from the water pools in the

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clearings?

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16 What proportion of the world’s insects live in jungles?

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22 How many chimpanzees are in the Ugandan forest

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17 What keeps the insect populations under control?

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23 Why do they raid neighbouring tribes?

18 How does a colugo get around the tree canopy?

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SCREEN EDUCATION

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Blackline Master | Planet Earth | Episode 8: Jungles Rainforest Ecosystems

SCREEN EDUCATION



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Technically the word ‘jungle’ refers to the emergent stage of a rainforest, the tangled mass of vines and re-growth in an area where the light has reached the ground, such as when a tree falls and there is a break in the closed canopy. The rainforest is normally quite clear on the ground as very little light reaches it and few plants can grow. There is a layer of leaf litter and a few large, leafed green ‘shade’ plants that can survive in the near dark conditions. More than half of the world’s species of plants and animals are found in the rainforest. This amounts to over 5 million species of plants and animals. Rainforests are forests created by very high rainfall, with minimum annual rainfall between 1,750 mm and 2,000 mm. The largest tropical rainforests exist in the Amazon Basin (the Amazon rainforest), Central America, in much of equatorial Africa from Cameroon to the Democratic Republic of Congo, in much of southeastern Asia from Myanmar to Indonesia and Papua New Guinea, eastern Queensland, Australia and in some parts of the United States. Despite the rapid growth of vegetation in a rainforest, the quality of the soil is often very poor. Rapid bacterial decay prevents the accumulation of humus – fertile organic material – and the high volume of rain on porous soils washes out nutrients quickly.

Rainforests play a major role in the global carbon cycle as stable carbon

The Trees Many species have broad, woody flanges (buttresses) at the base of the trunk. Originally believed to help support the tall tree, now it is believed that the buttresses channel water flow down the trunk and its dissolved nutrients to the roots. Trees are often interconnected in the canopy layer especially by the growth of woody climbers known as lianas, or by plants with epiphytic adaptations allowing them to grow on top of existing trees in the competition for sunlight.

Rainforest layers The rainforest is divided into four different parts, each with different plants and animals, adapted for life in that particular area.

Emergent layer This layer contains the emergents, a small number of the very largest trees that grow above the main canopy, reaching heights of 45-55 metres, although on occasion a few species will grow to 70 metres tall. Eagles, butterflies, bats and certain monkeys inhabit this layer.

Canopy layer The canopy layer contains the majority of the largest trees, typically 30-45 metres tall. The densest areas of biodiversity are found in the forest canopy, an almost continuous cover of foliage formed by interlocked treetops. The canopy, by some estimates, is home to forty per cent of all plant species, suggesting that perhaps half of

all life on earth could be found there. A quarter of all insect species are believed to exist in the rainforest canopy. True exploration of this upper habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows. Exploration of the canopy is still in its infancy, but other methods include the use of balloons to float above the highest branches and the building of cranes and walkways planted on the forest floor. The art of exploring forest canopy is called dendronautics.

Understorey layer There is a space between the canopy and the forest floor, which is known as the understorey and receives about five per cent of the sunlight. This is home to a number of birds, snakes, and lizards, as well as predators such as jaguars, boa constrictors, ocelots, and leopards. Insect life is abundant. Many seedlings that will grow to the canopy level if they get enough light are present, waiting in the understorey as saplings.

Forest floor This region receives only two per cent of the rainforest’s sunlight. Thus, only specially adapted plants can grow in this region. Away from river banks, swamps and clearings where dense undergrowth is found, the forest floor is relatively clear of vegetation, as little sunlight penetrates to ground level. It also contains decaying plant and animal matter, which disappears quickly due to the warm, humid conditions promoting rapid decay. Many forms of fungi grow here which help decay the animal and plant waste.

Human uses Many foods originally came from tropical forests, and are still mostly grown on plantations in regions that were

SCREEN EDUCATION

The undergrowth in a rainforest is restricted in many areas by the lack of sunlight at ground level. This makes it possible for animals to walk through the forest. If the leaf canopy is destroyed or thinned for any reason, the ground beneath is soon colonised by a dense tangled growth of vines, shrubs and small trees; the jungle.

pools and clearance of rainforest leads to increased levels of atmospheric carbon dioxide. Rainforests may also play a role in cooling air that passes through them. As such rainforests are of vital importance within the global climate system.



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formerly primary forest. Tropical rain forests are also the source of many medicinal drugs, with over half the medications originating from the rainforest. Tropical rainforests also provide timber as well as animal products such as meat and hides. Rainforests also have value as tourism destinations and for the ecosystem services provided.

Deforestation

Jungle/Tropical Rainforest Ecosystems – Discussion Questions 1. The birds of paradise males display to attract the rather ordinary looking females. This sounds the reverse of many species. Is it? Are there many species where females make the choice? 2. The rainforests are so humid that frogs can live permanently out of water. What are the usual requirements of frogs and other amphibia? 3. What is the mechanism by which the nutrients can be recycled in the poor soils of most rainforests and what organisms are involved? 4. The calugo is a nocturnal arboreal

mammal, a glider like those found in Australia and like the flying foxes. Most nocturnal animals feed at night to avoid predators and yet we see no predators here. What other reason may there be for a nocturnal lifestyle? 5. The chimpanzee is almost our closest relative – only the pygmy chimpanzee or bonobo of West Africa is slightly closer. What distinctly human characteristics can you identify in the behaviour of the chimpanzee tribe?

Extension Tasks •





Draw up a table or a visual presentation (poster) that shows the distribution of the tropical rainforest biome in the earth. Draw up a table, PowerPoint presentation or a visual presentation (poster) that shows a comparison between Tropical and temperate rainforest ecosystems. Discuss the nutrient recycling system in the rainforest soils. How might the misunderstanding of this fragile system have convinced humans that cleared rainforest would make good farmland?

SCREEN EDUCATION

Tropical and temperate rain forests have been subjected to heavy logging and agricultural clearance throughout the twentieth century, and the area covered by rainforests around the world is rapidly shrinking. It is estimated that the rainforest was reduced by about 58,000 square kilometres annually in the 1990s. Rainforests used to cover fourteen per cent of the Earth’s surface. This percentage is now down to between three and six per cent and it is estimated by some environmental groups that the remaining natural rainforests could disappear within forty years (mid twenty-first century). It has been estimated that large numbers of species are being driven to extinction, possibly more than 50,000 a year, due to the removal of habitat with destruc-

tion of the rainforests. Protection and regeneration of the rainforests is a priority for many environmental charities and organizations. Every minute about forty hectares of the world’s tropical rainforest is destroyed. At this rate, it is technically possible that all the rainforests in the world will have been destroyed by the year 2025. But it is doubtful that this rate will be sustained as the relative cost of logging rises with dwindling resources.

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ANSWER SHEET

Viewing Questions 1 Three per cent of the earth 2 Over fifty per cent of the species 3 Two per cent of sunlight reaches the ground 4 To attract potential mates 5 Up to 250 species of tree per hectare 6 Vines and climbers grow first 7 Various species of fig trees 8 Tamarins and monkeys 9 High in the trees, in the canopy 10 The loudest voice is most attractive 11 Over two metres rainfall per year 12 Rotting vegetation and bacteria 13 Species of fungi 14 The rain leeches (washes) out the nutrients very quickly 15 They recycle nutrients directly to the tree’s roots 16 Eighty per cent of the insects live in jungles 17 Parasitic fungi control insect numbers 18 It’s a glider 19 Because the soil is so low in nutrients 20 By using spider silk threads and air

bubbles to move around and avoid drowning 21 Medicinal clays that provide vitamins and reduce the toxic effects of some food plants 22 150 Chimpanzees in the tribe 23 To protect their territory and for meat protein

Discussion Questions 1. This seems to happen in most birds where there is a sexual dimorphism – the males and females look very different. It might be possible to have an amusing argument as to whether the same thing happens among humans in our society where males preen and ‘display’ with loud and outrageous behaviours. 2. Many amphibia never leave the water. Frogs and salamanders can, but in drier habitats, must return to water to lay their eggs. The immature form, the tadpole, must live in water. Notice that there is a tadpole in the water in the pitcher plant.

3. Fungi grow as tendrils on the tree roots. They break down the leaf mould and feed the nutrients directly into the roots of the trees – it is a symbiotic relationship. Other detritivores include arthropods, soil crustaceans which eat the leaf mould and the fungi also break down their droppings. 4. There may well be predatory eagles in the emergent trees that we have not seen. However, by feeding at night, the calugo avoids conflict with the monkeys in the canopy! 5. They are gregarious – tribal – and organized in their control of their territory. They seem to have a distinct social hierarchy and intelligent hunting behaviours. They are also extremely warlike and this may be an uncomfortable model for our own instincts and behaviours. BBC and Planet Earth are trade marks of the British Broadcasting Corporation and are used under licence. Planet Earth logo © BBC 2006. BBC logo © BBC 1996.

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SCREEN EDUCATION

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