Classifying leaves

Classifying leaves

Online interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
One of the ways scientists classify or group plants, is to look at ways the leaves of plants are the same. Some of the things they look at are:
  • the shape of the leaf
  • the vein pattern
  • whether the edge of the leaf is smooth or spikey
  • whether there is one leaf or more than one leaf branching from the stalk. 

Question

a)  Choose two leaves that have the same smooth edge. 

    • leaf option 1

    • leaf 2

    • leaf 3

    • leaf 4

Question

b)  Choose two leaves that have the same vein pattern.

    • leaf 1

    • leaf 2

    • leaf 3

    • leaf 4

Question 1Change answer

Explain how the vein pattern is the same in the two leaves you chose. 

Question 1Change answer

leaf 1leaf 2
 
c)  Moana chose these leaves. She said they were the same because:
  • both had 3 leaves that branched out from the stalk
  • both had a smooth edge
i)  Are the answers Moana gave correct? 
     YesNo
    Explain why you think this.
    
ii) Has Moana left out any other reasons why they were the same?
     YesNo 
    Explain why you think this.
     
Task administration: 
This task can be completed online with SOME automarking.
Level:
3
Curriculum info: 
Science, Investigating in science, Living World
Key Competencies: 
Thinking
Keywords: 
classification, leaves, observation
Description of task: 
Task: Look for the similarities and differences in leaf patterns to answer questions about observations and evidence.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations students have and the questions they ask.  
 
Capability: Gather & interpret data
This resource provides opportunities for students to discuss the data/evidence they collect and the patterns they notice in order to answer a question about classification and/or identification. 
Science capability: Gather and interpret data (TKI)
 
Capability: Critique evidence
This resource provides opportunities to discuss whether the data gathered provides evidence for the conclusions drawn.
Science capability: Critique evidence (TKI)
Science capabilities: 
Critique evidence, Gather and interpret data
Answers/responses: 
Questions Student responses
a) Choose two leaves that have the same smooth edge.
leaf-option-2-tp.pngleaf-option-4-tp.png
b) Choose two leaves that have the same vein pattern.
Any two of:

leaf-option-2-tp.pngleaf-option-3-tp.pngleaf-option-4-tp.png
Explain how the vein pattern is the same in the two leaves you chose. 
Accept any explanation that students can observe from the pictures. 
 
Students might look at more than one aspect/similarity: a more detailed explanation, e.g., 
  • the small veins branch out at the same place but at opposite sides of the central vein and the small veins branch out again before they reach the edge of the leaf.
They may also include comparison, e.g., 
  •  whereas the other leaf has many main central veins 
and/or measurement, e.g.,
  • ​There are 4 alternate veins branching off the main vein
  • The alternate veins branch off the main vein at an angle of about 45 degrees.
or
Students might look at one similarity: a simple explanation, e.g.,
  • small veins branch out from a central main vein.
c) i) Are the answers Moana gave correct? Explain why you think this. 
No [as both reasons are incorrect]. 
Explanation:
  • One has 3 leaves that branch from the base of the stalk. The other is one leaf that is divided into 3 parts.
  • One leaf has a smooth edge. The other has a spikey edge. 
c) ii) Has Moana left out any other reasons why they are the same? Yes/No
Explain why you think this.
Yes
Explanation:
  • Both have the same vein pattern. 
Teaching and learning: 
This key ideas in this task are about making precise observations and critiquing evidence.
Diagnostic and formative information: 
Questions Student explanations

b) Explain how the vein pattern is the same in the two leaves you chose. 
When looking for patterns in data, it is important to have precision and as much evidence as possible to support the statements/conclusions made. In this resource, some students made conclusions based on just a single observation, e.g., 
  • one central vein going out to edge.
Students also used everyday and imprecise language to explain their observations, e.g., 
  • They both come from one stalk and have thinner stalks attached to the bigger stalk and the veins both look cracked.
or imprecise measurement, e.g.,
  • The veins extend from around the same spacing and also they both split into smaller veins​
or some content knowledge beyond observation, e.g., 
  • Both leaves veins branch out, gradually decreasing in size and eventually joining together with other smaller veins for cell circulation.
c) i) Moana chose these leaves. She said they were the same because:
  • both had 3 leaves that branched out from the stalk
  • both had a smooth edge
Are the answers Moana gave correct? Explain why you think this. 
Some students paid attention to just one single piece of evidence, e.g., 
  • they are not the same because they do not have the same smooth edge 
  • I don't think that they are the same because the first leaf doesn't have three leaves coming out from the stalk, its just one whole leaf.​
Some students used non-scientific observations, e.g.,
  • Because the left picture looks like it has a bite mark in it which I think classifies it as non smooth.
c) ii) Has Moana left out any other reasons why they are the same? Yes/No Explain why you think this.
Some students gave very general reasons, e.g.,
  • they are the same because they both have a vein pattern
  • the similar shapes of the two leaves.
Based on a sample of 110 students completing the task on-line. 
Next steps: 
Capability 1: Gather and interpret data
An important component of this assessment is precise observation. Science knowledge is based on data derived from direct, or indirect, observations of the natural physical world. Looking for patterns in data requires many careful and accurate observations. Precise observations are the data we collect. 
To support students to make good observations, give them opportunities to describe what they see. A good strategy is to share observations so they build on others' ideas.
  • Can they make more than one observation?
  • Can they make precise observations that does not include knowledge beyond observation? 
  • Do they have sufficient vocabulary to give a rich and accurate description?
  • Can they look for relevant/science features? 
Capability 3: Critiquing evidence​ 
In order to evaluate the trustworthiness of data, students need to know quite a lot about the qualities of scientific tests/investigations. 
To support students to test their understandings about the qualities of scientific explanations, give them opportunities to ask each other questions about their investigations/pattern seeking. 
  • Can they decide if the amount of evidence/data given supports the explanation/conclusion? 
  • Is the evidence/data of sufficient quality to support the explanation/conclusion?  
The following Level 3 ARB resources are on Capability 1: Gathering and Interpreting Data and Capability 3: Critiquing Evidence of the Nature of Science.
They focus on accurate observations, looking at patterns and/or critiquing evidence.