Lesson No: 2        Unit Title: Variation and Classification                                         Unit No: 7D

 

 

    Lesson Title: Being Different  2                                                                                NC Ref:

 

 

Objectives:

MK —        There is variation between organisms of the same species.

SK -                        What a species is; word: species

CK -                      Examples of inter-species reproduction to produce hybrids; about continuous and discontinuous variation; about normal distribution; words: hybrid, continuous variation, discontinuous variation, normal distribution

   

Lesson outline:                                                                                                        

 

Starter:           Introduce the word species — can refer to worksheet 7Da/4 if "Bugs" activity was done previously

or 7Da/7 or page 44 from Expl Sci 7

 

Activityy

1. Pupils may have brought in pictures of different plants and animals from home (previous HW)

If they have, use them to recap variation, features, relationships and possible to introduce species

This can be done as whole class discussion or as small group exercise.

 

2.Investigate the differences between the same type of things e.g. species and plot distribution graph

A wealth of different things can be measured and plotted on graphs and charts. Possibilities include: variation between pupils (height, arm spans, eye colour, middle finger lengths) and lengths, volumes and masses of fruits.

NB: Measuring the volume of fruits using the water displacement method provides a useful link to Unit K

 

If  pupils are asked to measure their height (metre rules stuck to the wall) then line them up to show the distribution.

Discuss the range; sensitivity is needed - to reassure those at the two extremes that it is perfectly normal.

 

Measure and record the variations you have chosen

Plot as bar graph- see Expl Sc 7 page 46

Worksheet 7Da/6 could be used for this activity.

 

3. Introduce the terms continuous variation (a range of values that can and will change gradually e.g. height), discontinuous variation (there is not a range, a fixed result e.g. eye colour, ability to roll tongue) and normal distribution (bell shaped chart! - what we expect to find in things that show continuous distribution

 

 

Investigate the relationships between the differences (e.g. between pairs of features)

e.g. Do taller people have longer firearms? Are people with blond hair more likely to have blue eyes?

Plenary

Discuss the idea of bigger samples being needed to draw a firm conclusion; ask the pupils how confident they are of their conclusions; how strong is the correlation?

 

 

 

 

 

Homework:

Worksheet 7Da/6 or worksheet 7Da/7

 

 

Resources:

Photos of organisms of the same species

Worksheets 7Da/6 and 7Da/7

Graph paper Metre rules, 30cm rulers for measuring

 

 

Risk Assessment:

Care with metre rules

 Throughout this unit pupils should be encouraged to be sensitive to others when considering differences between them