Rainforest Lecture Notes Page 1

Rainforest Lecture Notes Page 1

Rainforest Lecture Notes page 1

Rainforest Notes

Answers to the skeleton notes are in red italics.

General Description:

  • 2 kinds – temperate and tropical. We will concentrate on tropical.
  • Sometimes called jungles.
  • Are evergreen, do not undergo seasonal changes.
  • Contain trees that connect at the topto form a canopy.
  • Link to picture of canopy
  • Link to drawingofcanopy Link to handout of same picture Link to "game"
  • Cover about 7% of earth’s surface. Link to graph showing 7%
  • Contain about ½ of all terrestrialplants and animals. Link to article on numbers of species.
  • Found in 4 main regions of the earth:
  • Central/South America
  • West Central Africa and Madagascar
  • Southeast Asia
  • Australia/New Guinea
  • Link to map of 4 areas


  • Mostly in the Torrid Zone. Link to Torrid Zone map.
  • Rain and warm temperatures support constant plant growth.
  • Average is 68o to 84o.
  • Temperature never below 64 o.
  • Little to no seasonal change.
  • 80 inches of rain per year minimum.
  • Up to 200 inches per year. Links to different rainfall amounts1 2 3 4 5
  • The purpose of the links is to show you that biology is a soft science.
  • That means there are often not any definite answers, only people’s opinions.
  • Rains almost every day – a downpour or a misty shower.
  • Often cloudy
  • Light winds in canopy, no wind in under story.
  • Some coastal rainforests may experience hurricanes.
  • Some areas that COULD be tropical rainforest have a dry period – so the trees lose their leaves – these are calleddeciduous rain forests. Link to Madagascar deciduous forest.


  • Tropical rain forests grow at all elevations
  • Even over 10,000 feet.
  • Most grow at less than 3000 feet.


  • Deep, reddish –yellowcolor.
  • Reds and yellows come from iron and aluminum oxides (rust)
  • Link to oxidesiron aluminum
  • Low nutrients.
  • Conditions are so good for growing that the plants (trees) absorb all the nutrients from the soil, making the soil poor.
  • Link to cornfield
  • Link to fertilizing the soil
  • Link to rainforest clearcutting
  • Link to soil profile
  • Indonesian and Central American Rainforest have better soil because their volcanic soil has more nutrients.
  • Most fertile soil is at the surface, from the decay of dead vegetation.
  • Most roots are at the surface.
  • In dense shade there is little plant growth so the soil is better.

Plant Adaptations


  • Thin smooth bark that is shed frequently.
  • Shedding removes epiphytes, keeping the bark clean.Link to epiphytes. Link to clean tree bark You can see the flaking bark trick doesn’t always work!
  • Some guess the smooth bark also helps keep other plants from growing on them.


  • Climbing woody vines that have their roots in the ground but grow high into the canopy. Link to lianas pictures We have a similar situation here with grape vines.

Driptips and glossy leaves

  • Many tropical rainforest leaves have special tips to let water drain off quickly.
  • Some guess these tips and the glossy leaves help prevent fungus, mold, and bacteria from growing.Link to drip tip picture

Large Leaves in understory

  • Can absorb more lightin the dimly lit understory Link to picture

Buttresses,prop, and stilt roots.

  • Rainforest ground is typically shallow and wet. Plants have stilts or buttresses to help anchor them to the ground and keep the tree from falling over. Some of these buttresses may be 30 feet tall. Link to tree with stilts. Montage of photos of buttresses.

Epiphytes, epiphylls

  • Plants that live on the surface of other plants, but not as parasites.
  • MostlyOrchids, bromeliads, ferns, andPhilodendronrelatives.
  • Epiphylls are smaller and live on theleaves. Epiphylls picture


  • Members of thepineapplefamily.
  • Most grow ontree branches.
  • Leaves arewaxyand forma tank that holds water, sometimes as much as 12 gallons!
  • These mini ecosystems cansupport a variety of animal lifeupto and including frogs.Bromeliad with frog


  • Tropical rainforest trees that live in saltwater.
  • Have specialized roots that allow them to “breathe” and excrete salt.
  • Name refers to an individual tree and to a forest of trees.
  • Often are “protected” species.
  • Germinate underwater! Link to mangroves underwater Mangroves

Pitcher Plants

  • Carnivorous plants that have a deep water-filled cavity that catches insects, attracting them with sweet or foul odors.
  • Insects fall in, can’t get out and are digested in a number of ways – plants get minerals, mostly nitrogen and phosphorus.
  • Only grow in poor soil, such as rainforests.
  • Link to pitcher plants

Some common plants

  • Link torainforest plants
  • As you or I go over these, be able to name at least 4.
  • Plants that you picked.

Medicine from the Rainforest reference link

  • Today at least 120 chemicals from plants used in medicine. (They don’t all come from the rainforest.)
  • There are over 100 drug companies worldwide engaged in finding active plant chemicals from all over the earth, not just rainforests.
  • The chemicals may not be used directly, but have been synthesized.
  • Click on the reference link to see a list of plant chemicals used so far. There is also a list of 7 chemicals made into anticancer drugs.


  • As diverseand abundantas the plant life because of warm temperaturesand plentiful moisture.
  • Most animals live in the high canopy.


  • Animals without a backbone.
  • Includes centipedes, millipedes, spiders, crustaceans, and insects. Also includes worms and leeches.
  • Insects are the most successful group of rainforest animals.
  • Link to army ants Link to leechesLink to cockroach video Link to Rhinoceros beetle video
  • Most invertebrates eat plants or decaying animals.Link to Postman butterfly Food is the passionflower vine
  • Some spiders are big enough to eat lizards, mice, and birds. Link to Goliath SpiderGoliath spider picture


  • Tree frogs and poison dart frogs. Link to poison frog pictures.
  • Some tree frogs can glide. Wallace’s gliding frog


  • Basilisk lizard can run on water. Link to video of running lizard.
  • Komodo dragon is the largest lizard – gets up to 10 feet long.
  • Have bacteria infested saliva that they use to kill their prey. It takes up to a week.
  • They are strong swimmers.
  • They can climb trees. Picture of dragon
  • Chameleon – change colors to match their moods, temperature, and amount of light – have independently moving eyes and a very long sticky tongue that they use to catch insects.Link to chameleon eating a larva


  • Most are brightly colored
  • Have short broad wings.
  • Some have feet adapted to climbing.
  • In general, cover the range of all possible food sources, from plants, seeds, snails, to fruit, monkeys, and sloths.
  • Harpy Eagles Link to site on harpy eagle
  • Largest and most powerfuleagle on earth.
  • Eat large prey, likemonkeys and sloths.
  • ParrotsLink to parrot pictures Link to list of all known parrot species
  • Many are endangered, such as the world’s largest, the Hyacinth Macaw.Link to Hyacinth Macaw.
  • Jungle fowl are the ancestors of the chicken.
  • Good runners, but poor fliers.Jungle fowl info.


  • Common ones are bats, sloths, okapi, gorillas, jaguars, and many others.
  • Bats are the only mammals that can fly. Many eat fruit and are responsible for pollination. What is pollination? What animal pollinates most of the flowers in our area? Bees.
  • Link to bats
  • Sloths
  • Spend their entire life hanging upside down.
  • Even their furis upside down. The part of the fur is in the middle of their stomach.
  • They are herbivores.
  • They may stay in the same tree for years.
  • They move so slowly that algae grows in their fur which helps camouflage them.
  • It has a greater metabolic temperature range than any other mammal – from 74 to 92 degrees F
  • It has a smaller muscle mass to body weight ratio than any other mammal.
  • Link to sloths
  • OkapiLink to Wikipedia on okapi
  • Discovered in 1901.
  • Relative of giraffe.
  • Can clean its own eyelids and clean its earswith its bluetongue.Tongue picture
  • Gorilla
  • The largest primate.
  • Males get to 6 feet tall and weigh 400 pounds.
  • They are endangered because of habitat destruction, the Ebola virus and use as food.
  • Link to picture.
  • Jaguar Wikipedia on jaguar.
  • The 3rd largest cat after the lion and tiger.
  • Has the most powerful bite. Kills it’s prey by crushing its skull.
  • Likes to drop on its prey from an overhanging tree branch.

Importance of the rainforests

  • Contains an estimated ½ of all plants and animals.
  • They are an important source of medicines and fewer than 1% have been tested for medicinal properties.
  • Originally ¼ of all medicine came from rainforest (source Arborvitae Magazine June 96)
  • Many food items come from rainforests, including coffee, nuts, spices, rice, bananas, etc.
  • Tropical rainforests may help regulate climate.
  • Removing them may cause deserts to form.
  • Help prevent flooding by soaking up lots of rain.
  • Home to about 50 million native people.
  • Important to some countries in what is known asecotourism. Link to ecotourism

Survival of the Rainforests

  • Forests are disappearing throughout the tropics as trees are cleared to provide land for farming.
  • This destroys the habitat for plants and animals.
  • Many governments are working to protect the rainforest.
  • Trees are cleared for other reasons, such as coltan for cell phones, laptops, playstations, etc.
  • Some claim that cutting downrainforest causes desertification. Basically this is a process where deserts occupy formerly productive/forested land.
  • Contrary to popular opinion, scientists do not agree on what causes desertification.
  • Click on this link on desertification and scroll down to countering desertification if you are interested.