Category Archives: Amazon Biodiversity Teasers – Answers

Answers and links to questions about Amazon animals and plants.

Amazon Biodiversity Teaser #3 – Answer

Question: Which type of animal could have an ecological impact on the abundance and diversity of the Amazon rain forest?

Answer Choices: A) Fish B) Snakes C) Frogs D) Butterflies

Correct Answer: A) Fish

Summary: Seed dispersers are crucial players in any forest ecosystem. Seed dispersal studies have traditionally focused on species of birds, bats, monkeys and rodents, but a new study by Jill T. Anderson of Duke University suggests that there could be a correlation between the populations of large fruit-eating Amazonian fish and the abundance and diversity of certain tree species in the Amazon rain forest. The fish involved in the study are the tambaqui and the pirapitinga (photo), both known as pacu fish, are massive fruit-eating fish that live in the Amazon River and its tributaries. The tambaqui have an average weight of about 33 pounds and the much larger pirapitinga are an average of 200 pounds each. These fish are classified as long-distance dispersers. They eat the seeds of trees that drop into the water and later drop them in a new place along the river. These fish are being overexploited by local fisherman and in turn the species are dropping in population. Dr. Anderson explains that a drop in these species’ populations could result in less abundance and diversity in the Amazon rain forest.

Source: FAO Non-Wood News 23rd Edition; Giant fish help the Amazon rain forest grow; November 2011;

Amazon Biodiversity Teaser #2 – Answer

Question: The Amazon Basin contains what percentage of known species (plants and animals) on Earth?

Answer Choices: A) 1% B) 10% C) 20% D) 45%

Correct Answer: B) 10%

Summary: The Amazon Basin is abundant in biodiversity. The number of known species on earth that have been formally identified is about 2 million species, making the Amazon home to about 200,000 of these. This includes roughly 40,000 plant species, 3,000 freshwater fish species and more than 370 reptile species. However, estimates for the total number of species on earth range between 5 million and 30 million. These extremely large estimates exist because of multiple studies that have been done in the Amazon rainforest that suggest there could be many, many more species on earth than previously believed. Perhaps the most significant study on this topic was conducted by Terry Erwin, a biologist that specializes in beetle populations. In the Amazon, Erwin sprayed pesticides into the forest canopy which caused any insect to fall to the forest floor (see picture here). After examining the fallen insects, he found a high number of undescribed species, as well as over 1,100 species of beetles alone from the canopy of a single species of tree (L. seemannii). Using the Amazon as an illustration for what could be living in other rainforests, he has estimated that the total number of species in the world could be much larger than the meager two million already identified. This leaves plenty of unidentified, “mystery” species that are still out there, many possibly living within the Amazon.

Sources: World Wildlife Fund; Amazon: World’s largest tropical rain forest and river basin;;
The Environmental Literacy Council; How many species are there?;;
Terry Erwin; Tropical forest canopies, the last biotic frontier; 1983; Bulletin of the Entomological Society of America.