Purpose of task: Students to learn about and annotate diagram of “Stratification of a tropical rainforest” whereby the vertical layers of this habitat are divided into microhabitats receiving a differing range of abiotic and biotic factors.
A tropical rainforest is the most complex of land ecosystems and supports the largest number of species, thus having the greatest biodiversity. The rainforest habitat can be divided into four vertical layers, or strata, that represent zones of different vegetation. It is this stratification which makes available a variety of microhabitats; each receiving a differing range of abiotic and biotic factors. Species composition varies at each microhabitat according to the altitude, rainfall, light levels, soil type and drainage.


  • Play short audio file to get class in the rainforest set of mind!
  • Students to work individually whilst completing Stratification task.
  • Rainforest diagram will need to be copied and distributed to each member of the class.
  • Depending on time allocation for lesson, interest and learning needs of students, the extension activity is available and may be completed within small groups.

rainforest stratification diagram, http://bio-ditrl.sunsite.ualberta.ca/detail/?P_MNO=1834

In the given profile of a rainforest (see right), occurring in northern Borneo, one can see evidence for the existence of stratification. (In reality, such layers are not as clearly defined)
Q.1. Draw horizontal lines on the rainforest diagram to show where you think the boundary of each vertical layer lies.

Q.2. After reading the following descriptions, match them with the four vertical layers. Then annotate the diagram with these layers:
ground layer (forest floor), understorey, canopy, emergent
  • Densest layer, comprises saplings, tree ferns & palms, small trees and large shrubs
  • Scattered, crowns are exposed above the canopy, tallest trees, include the Brazil nut tree, subjected to the most sunlight
  • Thinnest layer, comprises of ferns, mosses, fungi, lichen, decomposition of leaf litter and other decaying matter, subject to the least sunlight
  • Blocks most sunlight, fills the gaps between the emergents, an abundance of leaves, flowers and fruits, aggregation of treetops appear as an immense green carpet

Q.3. Find out the meaning of the word "liane" and colour in any that you think are represented in the diagram. In which stratification layer would you expect to see epiphytes (eg. orchids) and lianes? Why might epiphytes be described as "perching plants"?

Q.4. List two abiotic factors and explain how they vary with each of the four vertical layers.

Q.5. Within this rainforest habitat live the banana fig (Ficus pleurocarpa) at approx. 25m tall and the soft tree-fern (Dicksonia antarctica) at approx. 10m tall. Consider how each plant provides a different microhabitat and list some biotic and abiotic factors within each.

Q.6. Predict what might happen next after a tropical cyclone destroys the rainforest canopy (discuss sunlight levels in your response).

*Extension activity:
Small groups to construct a model of a rainforest using mainly recycled materials. Each model should indicate all four vegetation levels within the rainforest. In each stratified level include an animal and plant unique to that level. Model should attempt to show scale, detail, colour, life and relationships.

Student Assessment
Students are given a set amount of time in class to complete "Stratification" activity, through which the teacher sights the progress of all students as well as assisting with associated student questions. Afterwhich, responses to the six questions will be discussed by the whole class with student answers volunteered.
Finish the lesson with the short video clip "Canopy Climbing in the Rainforest", from http://www.evtv1.com/player.aspx?itemnum=1674

Useful Resources
EVTV1 (2010). Canopy Climbing in the Rainforest. Retrieved 24 October, from http://www.evtv1.com/player.aspx?itemnum=1674
Inkaterra (2010). Vertical stratification. Retrieved 24 October, from http://www.inkaterra.com/en/reserva-amazonica/inkaterra-canopy/vertical-stratification
Maricopa Community Colleges (2010). Community and Ecosystem Dynamics-Classification of Communities. Retrieved 13 October, from http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookcommecosys.html
Tripod (unknown). Rainforest stratification. Retrieved 24 October, from http://hiskey.tripod.com/rainforest-strat.html
University of Alberta (2004). Biological Sciences. Retrieved 14 October, from http://bio-ditrl.sunsite.ualberta.ca/detail/?P_MNO=1834
Wet Tropics Management Authority (unknown). Rainforest explorer. Retrieved 24 October, from http://www.wettropics.gov.au/st/rainforest_explorer/Resources/Documents/8to9/HowTo/Model.pdf

Links to Curriculum
VCE Biology Unit 2: Organisms and their environment
Area of Study 2: Dynamic Ecosystems
Key knowledge: components of ecosystems: communities of living organisms, ecological groupings; ecological niche

Victorian Curriculum Assessment Authority (VCAA) VCE Biology web page at http://www.vcaa.vic.edu.au/vce/studies/biology/biologyindex.html