Content
Introduction & Outcomes
In this topic, we examine the driving forces behind the development of today’s tropical forests. We look at how the continents have moved over time and relate these movements to the evolution of different plant and animal groups. We examine how evolution and extinction work, placing particular evidence on the speciation of organisms entering new habitats. We examine the role of climate change in detail, as well as the role of past sea-level changes. Finally, we look at the influence that very large-scale disturbances have had.
We then examine the many different forces that have occurred over time to drive the evolution of tropical forests. Understanding these is critical to learning why tropical forests are so diverse. In examining the driving forces, we are looking at the very large-scale or long-term processes that drive the evolution of forests. These forces are massive – such as plate tectonics, affecting the entire surface of the Earth. They drive not only the evolution of tropical forests, but also the evolution of all life on Earth.
By the end of this topic, you should be able to:
- Describe when Pangaea, and then Laurasia and Gondwana, broke up to form today’s land masses, and how the timing of this break-up corresponded with the evolution of different lifeforms.
- Contrast the processes controlling evolution and extinction.
- Evaluate the importance of climate change in different parts of the tropics in determining present-day flora and fauna.
- Outline the role that sea-level change has played in determining the composition of tropical forests, especially in South-East Asia.
- Evaluate the role of large-scale disturbances in extinctions and subsequent re-colonization.
- Assess the relative importance of plate tectonics, climate change and evolution in the constitution of present-day tropical forest flora and fauna.
- Explain the distributions of different groups of organisms in tropical forests.
Topic Readings
Required Readings
- Ghazoul, J. and Sheil, D. 2010. Tropical rain Forest Ecology, Diversity, and Conservation. Oxford, Oxford University press, 516 pp. Chapter 6.
Optional Readings
- Corlett, R.T. and Primack, R.B. 2011. Tropical Rain Forests. An ecological and biogeographical comparison. 2nd edition. Chichester, UK: Wiley-Blackwell. Chapter 8.
- Kricher, J. 2011. Tropical Ecology. Princeton, New Jersey, USA: Princeton University Press, 632 pp. Chapter 2.
- Macleod, N. 2013. The great extinctions. What caused them and how they shape life. London, UK: Firefly Books, 208 pp.
- Morley, R.J. 2000. Origin and evolution of tropical rain forests. Chichester, John Wiley & Sons, 362 pp.
- White, M.E. 1998. The greening of Gondwana. The 400 million year story of Australia’s plants. 3rd edition. East Roseville, NSW, Australia: Kangaroo Press. 256 pp.
- Willis, K.J. and McElwain, J.C. 2002. The evolution of plants. Oxford, Oxford University Press, 378 pp.
Self-check Quiz
After viewing topic presentations, take this self-check quiz to check your own progress. This quiz is designed to see how well you remember some of the more important issues presented in the module. There are five questions, and each has a potential of 4 answers, only one of which is correct. When you are ready, click the link Self-check Quiz 1.2 to start taking the quiz.
Pre-readings and Discussion (For certification)
Once you have read Chapter 6 Ghazoul, J. and Sheil, D. 2010. Tropical Rain Forest Ecology, Diversity, and Conservation, choose to post one thought provoking question related to the material that you have read, and remember to answer/respond to at least one other student’s question on the discussion board Online Discussion Module 1.
Graded Assignment (For certification)
Six-sentence Answer #1
Please refer to the course pages on graded assessments to see details of the Six-sentence Answers (6SA) exercise. You should not attempt to do this assessment until you have read and fully understood the requirements.
The Case
You are a member of a major international forest consultancy firm that specializes in doing surveys of forests around the world. You have access to field teams and the latest surveying equipment, include LiDAR. Your company has taken on a contract with the UN-REDD (United Nations Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries) to survey the forests on a very large island in South-East Asia, and you have the full cooperation of the government. A starting point for this project is to map the forests of the island. You know relatively little about the island, although there is a large volcano in the middle, reaching almost 5000 m above sea-level, and most of the rain falls on the west side of the island, leaving the rain shadow on the east side with almost no rain.
Your CEO comes to you asks that you provide a recommendation on how to classify the forests in this mapping exercise. Please provide an answer, using the 6SA format, and providing a well-supported recommendation for the way the company should proceed.
Remember to follow the structure of the 6SA outlined in the section on graded assessments.
Formatting:
- Double-space the text.
- 12-point font in New Times Roman or Calibri.
- Put your name (Family or last name, followed by your first name), student number, the title “Topic 1.1 assignment”, and the date at the top of the first page.
- Name the e-file: your Family or last name_your first name_ Topic 1.1_Assignment.doc (or .docx). Example: Innes_John_Topic 1.1_Assignment (or .docx).
- Standard English usage, clear writing style.
- All assignments should be submitted through Canvas before the deadline.
Topic Summary
In this topic, we look at the processes that have brought about present-day tropical forests. We focus on plate tectonics (continental drift), evolution and extinction, climate change, sea-level change and large-scale disturbances. Together, these and a variety of other more immediate processes (examined in the next module) have influenced the way in which tropical forests have developed into their present-day form.
Topic Self-review (For self learning)
To review what you have learned in the topic, you are encouraged to use the following reflection questions as a study guide to do a self-review for the topic:
- What was the role of the breakup of Pangaea into Laurasia and Gondwana in the development of present-day tropical forests?
- How important are large-scale disturbances, such as asteroid impacts, in extinctions?
- Why do oceanic islands often have large numbers of endemic species?
- How did the Quaternary glaciations affect South America and Africa? Were the effects the same, or did they differ?
- What is so special about the flora and fauna of the Seychelles?
- How was Hawaii colonized by so many plants and animals?
- How important is long-distance dispersal as a means of colonizing new land areas?
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