Student Activity 5.1

Teacher Information Sheet
Plant Evolution
Leaf Margin Analysis
Formula Use
y = 3.2093x - 2.7844 (derived for the Northern hemisphere)
To work out a value for y, use a simple maths equation to find what percentage of
leaves are untoothed, and slot this into the equation as y
Rearrange the equation to find a value for x – this is the mean annual temperature
the class have worked out using their leaves.
- Climate Leaf Analysis Multivariate Programme
Programme website:
- another method that uses leaf characters to calculate the mean annual temperature of a
site where plants are growing, it also tells you the mean annual precipitation and other
values that may be of interest that the leaf margin analysis alone does not give
- can therefore be used with fossils from a certain area to predict the temperature of that
- Example: Leaves of woody angiosperms tend to have more "leaf teeth" in colder climates
than in warmer ones
- Teacher information sheet:
- NOTE: This is well worth a go with more able TY classes, please be sure to use it yourself
before introducing to the class as it is a much more complex method of calculating mean
annual temperature.
Leaf characteristics are available here
- Scroll to the bottom of page to find a printable pdf version
- See left menu bar to download size sheet and results sheets
Students may fill out the sheets in the classroom OR go to computer room to input
these onto the computer results sheet to get the end result - mean annual
temperature for the area, along with mean precipitation values etc
TIME: this will take at least a double class depending on number of samples
collected, samples may need to be held to be completed in following class
Flower dissection needed here to distinguish between main flowering parts of plant
(male and female NB). This should be drawn into copy and identified in class with
real flower.
Students should cover the basics of plant reproduction in line with Leaving Cert
biology course, in less detail. Discuss methods of pollination (wind V animal)
Pollination Tube Practical:
Follow instructions given to make solution for pollen tube growth.
Calcium is essential here for optimum growth of pollen tube.