written by: kailash nrseed dispersal models to understand different seed dispersal methods. written...

Seed Dispersal ModelsTo understand different seed dispersal methods.

Written By: Kailash NR

Seed Dispersal Models 2020-04-08[minor]2.2Release:Guide ID: 223 -

This document was generated on 2020-04-11 05:45:32 PM (MST).

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INTRODUCTION

Seed dispersal is the movement or the transport of seeds from one place to another by a vector(animal, wind, water). Seeds are dispersed naturally and manually.

In this TACtivity, we will learn the different patterns and modes of seed dispersal.

TOOLS:Scissors (1)Pen/Pencil (1)

( for marking the reference )Glue (1)Scale (1)

PARTS:Rectangular Paper Strip (about 15 cm X

4 cm) (1)Rectangular Paper Strip (about 12 cm X

2 cm) (1)Rubber Foam (8mm) 3 cm *4 cm (1)Binding Wire (30 G), 30 cm (1)Thermocol Ball (2 inch * 2 inch) (5)Wooden Skewer (16 cm) (1)Cotton (1)

approximate to size of lemon



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— Precaution

Exercise caution while using scissors/cutters.

— Step 1 - Rotocopter - Marking the Paper Strip

Cut a paper into a rectangular strip of measurement 15 cm X 4 cm.

Along the length, mark two points at 5 cm from one end. These markings should be at the oppositeedges as shown in picture.

At the markings, draw two 1.5 cm lines along the width of the paper strip.



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— Step 2 - Making of Rotocopter I

Take the same end from which 5 cm markings were measured, mark the mid point at the edge asshown in picture.

Extend the mark along the length to draw a 3 cm line.

Cut along all the marked lines using scissors.

— Step 3 - Making of Rotocopter II

Now take the longer portion of the paper strip and make two creases (along the length), which are1.5 cm from the respective edges.

Fold along the creases made. Also, secure the folds by folding a small portion of the paper at theend.

Stick a piece of transparent tape, if necessary.



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— Step 4 - Making of Propellers

Hold the paper at 3 cm where cut was made earlier, gently fold the two cut parts in the oppositedirection, so that it looks like 'V' from the side view.

These will act as the propellers.

— Play!

Drop the roto-copter from a height ofat least 5 feet to observe it, inaction, as it rotates about the verticalaxis and descends slowly.



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— Step 1 - Making the Paper Fish I

Cut a rectangular paper strip of measurements 12 cm X 2 cm.

At a distance of 1.5 cm from each end, mark 1 cm line, along the width of the paper strip. Makesure these lines originate from the opposite edges.

Cut along the marked lines using scissors.

— Step 2 - Making the Paper Fish II - Lock the Ends

Fold the ends and lock them by passing the cuts through each other to make it look like a fish.

Do not crease the paper after folding!



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— Play!

Throw the fish up in the air and observe its rotation in the air, as it descends.

— Step 1 - Simulating Animal Fur I

Mark an approximate midpoint on the foam piece.

Insert a skewer through the midpoint marked earlier on the foam piece.

The skewer should not come out from the other end.



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— Step 2 - Simulating Animal Fur II

Apply glue evenly on the other side of the foam piece.

Stick the cotton to the glued area of foam piece.

Pull the cotton a bit and make it wispy.

Seeds get stuck easily in the wispier cotton.

— Step 3 - Preparing the Burrs

Take a binding wire of 30 cm length.

Measure 1.5 cm and mark using a sketch pen.

Cut at the 1.5 cm mark.

Cut the entire length of binding wire to get at least 15 pieces of 1.5 cm each.



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— Step 4 - Making of Seeds

Insert binding wire through a thermocol ball such that a small portion of wire comes out on theopposite side.

Insert all 5 pieces of binding wire through the thermocol ball in all possible directions.

Similarly, repeat the procedure for another 2 - 3 more seeds.

— Play!

Press the cotton part of the stand against the seeds.

Observe the seeds sticking to the cotton.



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— Troubleshooting

Animal fur model - thermocol breaking - Rotate the thermocol while inserting the binding wire.

Animal fur model - thermocol balls not sticking to cotton - Make only one layer of cotton to stick tothe foam.

Rotocopter model - not flying longer - Propeller length too short.

Paper fish - paper creased after completion is very loose - Lock mechanism is not equally spacedfrom the ends.

— Suggested Variations

Some seed disperse by explosion due to the internal tension within the seed. Try ballistic model ofseed dispersal.

Some plants have tiny holes in their seed capsule. When the wind blows, the holes in the capsuleslet the seeds to fall on the ground. Try dispersal by shaking method.

In some plants, due to gravity fruits undergo abscission and fall to the ground, where their seedsare released.

For more variations, Go to Seed Dispersal Model (Variations).



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https://www.tactivity.in/Guide/Seed+Dispersal+Model+(Variations)/224#s8995

written by: kailash nrseed dispersal models to understand different seed dispersal methods. written...

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