Sept. 21, 2005

Acquired Characteristics

Many 19th-century scientists believed that "acquired characteristics"—features that organisms acquire during their lives—were passed on to offspring. Even Charles Darwin, as a child, claimed he could make flowers turn colors by watering them with colored water. In this experiment you can answer the questions yourself: Can acquired characteristics be passed on? Do plants inherit features acquired by the seeds from which they sprouted?

What you need

• spoons
• plate (glass or metal)
• bottles of food coloring (three or more colors)
• a packet of radish seeds
• several small plant pots, or empty yogurt containers with holes poked in the bottoms
• several plastic plant labels or popsicle sticks
• soil

Any kind of seeds will do, but radish seeds are the best because they sprout quickly. Look for food coloring in your kitchen, or buy a package with four different colors.

Put a spoon flat on the plate, and squeeze a couple drops of one color of food coloring into it; then take two radish seeds and drop them into the spoon. Repeat the process with all the different colors you have, each in a different spoon with two new seeds. If you only have two or three colors, you can combine one drop of each to make a new color: add blue to red to make purple, and so on. Allow the radish seeds to soak up the color.

Take your small plant pots (or yogurt containers) and fill them most of the way with loose soil, and pat it down. If you have two seeds being dyed red, for example, take two plant labels or popsicle sticks and write "Red" on each one and stick them into the dirt, one for each pot. Repeat the process for each color until you have a row of pots all identified according to color.

Then, one by one, pick up each dyed seed and place it into an appropriately labeled pot. Push each seed about a quarter inch below the soil level and smooth it over. Place the pots in a sunny location, preferably on a tray or dish. Water the seeds thoroughly at first, and every day sprinkle a little water to keep the soil moist (but not soggy).

Now for the hardest part: wait! Radish seeds usually sprout in less than a week—sometimes in as little as two or three days. When the seeds sprout, will their leaves match the colors on the labels? Did the food coloring soak into the seeds and permanently dye the plants? Or will all the sprouts be green, as usual?

Once you've completed this activity, you'll know whether or not environmental influences directly alter basic genetic structure.

Reprinted with permission from Darwin and Evolution for Kids: His Life and Ideas, with 21 Activities by Kristan Lawson. Published by Chicago Review Press, distributed by Independent Publishers Group (www.ipgbook.com). Copyright ©2003 by Kristan Lawson.

Talk Back: Do you have any comments about this activity? Send them to us using the form below.

I have my parent's permission to submit this.
First name:		Age:
City:		State:	AK AL AR AZ CA CO CT DC DE FL GA HI IA ID IL IN KS KY LA MA MD ME MI MN MO MS MT NC ND NE NH NJ NM NV NY OH OK OR PA RI SC SD TN TX UT VA VT WA WI WV WY
E-mail:
Comment: