Transcript
Teacher's/Lecturer's Sheet Printed: 30.03.2017 15:22:12 | P8014000
Dispersal of seeds (Item No.: P8014000) Curricular Relevance Area of Expertise: Biology
Education Level: Age 14-16
Topic: Plants
Subtopic: Reproduction in plants
Experiment: Dispersal of seeds
Difficulty
Preparation Time
Execution Time
Recommended Group Size
Easy
10 Minutes
20 Minutes
2 Students
Additional Requirements:
Experiment Variations:
Pine-cones or spruce-cones
Keywords: Anemochory, Zoochory, Anthropochory, Barochory, Hydrochory, Allochory
Task and equipment Information for teachers Additional Information For a seed plant, not only the production of numerous seeds, but also their widest possible dispersal, are of great importance fort he preservation of the species. Many plants have developed different mechanisms to ensure the dispersal of their seeds. The seeds of the pine tree or the spruce examined in this experiment get dispersed by the wind (anemochory). Besides this mechanism for the dispersal of seeds there are still more; overall, the mechanisms fort he dispersal of seeds are split into 4 to 6 types. In addition to the dispersal by wind, these are: dispersal by animals (zoochory), dispersal by humans (anthropochory), dispersal by gravity (barochory), dispersal by water (hydrochory) and dispersal by external means (allochory).
Hints on Set-up and Action Because of the waiting time at least 3 days are needed for carrying out the experiment.
Robert-Bosch-Breite 10 D - 37079 Göttingen
Tel: +49 551 604 - 0 Fax: +49 551 604 - 107
[email protected] www.phywe.com
Student's Sheet Printed: 30.03.2017 15:22:12 | P8014000
Dispersal of seeds (Item No.: P8014000) Task and eluipment Task How get seeds dispersed? Examine where the seeds are situated in a pine-cone or a spruce-cone and determine which devices or actions serve their dispersal.
Eluipment
Position No. 1
Material
Order No.
Glass beaker DURAN®, tall, 600 ml 36006-00
Quantity 1
Additional material Pine-cones or spruce-cones
Robert-Bosch-Breite 10 D - 37079 Göttingen
Tel: +49 551 604 - 0 Fax: +49 551 604 - 107
[email protected] www.phywe.com
Student's Sheet Printed: 30.03.2017 15:22:12 | P8014000
Set-up and procedure Examine a pine-cone or a spruce-cone which has open (sloped) scales (Fig. 1), and determine where the seeds are situated. Examine the constitution of the seed and write down your observations in the report.
Fig. 1
Place the cone in a beaker filled with water (Fig. 2) and wait for 24 hours. What has changed on the next day? Write down your observations in the report.
Fig. 2
Take the cone out of the water and place it somewhere warm (e.g. exposed to sunshine or on a warm radiator). What has changed on the next day? Note your observations in the report.
Robert-Bosch-Breite 10 D - 37079 Göttingen
Tel: +49 551 604 - 0 Fax: +49 551 604 - 107
[email protected] www.phywe.com
Student's Sheet Printed: 30.03.2017 15:22:12 | P8014000
Report: Dispersal of seeds Result – Observations 1 (10 Punkte)
Describe the constitution of the seed of a pine tree or spruce.
Result – Observations 2 (10 Punkte)
How has the cone changed after lying in water for one day?
Robert-Bosch-Breite 10 D - 37079 Göttingen
Tel: +49 551 604 - 0 Fax: +49 551 604 - 107
[email protected] www.phywe.com
Student's Sheet Printed: 30.03.2017 15:22:12 | P8014000
Result – Observations 3 (10 Punkte)
How has the cone changed, after lying on a warm and dry place for one day?
Evaluation – Question 1 (10 Punkte)
Where are the seeds situated in a pine-cone or a spruce-cone?
Robert-Bosch-Breite 10 D - 37079 Göttingen
Tel: +49 551 604 - 0 Fax: +49 551 604 - 107
[email protected] www.phywe.com
Student's Sheet Printed: 30.03.2017 15:22:12 | P8014000
Evaluation – Question 2 (10 Punkte)
How does the position of the scales change when the cone is dried, moistened or wetted?
Evaluation – Question 3 (10 Punkte)
Which position of the scales is necessary for seed dispersal?
Robert-Bosch-Breite 10 D - 37079 Göttingen
Tel: +49 551 604 - 0 Fax: +49 551 604 - 107
[email protected] www.phywe.com
Student's Sheet Printed: 30.03.2017 15:22:12 | P8014000
Evaluation – Question 4 (10 Punkte)
What is improved by the so-called wings of the seeds?
Evaluation – Question 5 (10 Punkte)
Which weather conditions are favourable for seed dispersal and which are unfavourable? Why? Which adaptation phenomenon which is favourable to seed dispersal exists between the weather and the corresponding position of the scales of a pine-cone or a spruce-cone?
Robert-Bosch-Breite 10 D - 37079 Göttingen
Tel: +49 551 604 - 0 Fax: +49 551 604 - 107
[email protected] www.phywe.com
