Month: January 2010 (Page 2 of 7)

Seed of the Week: Pine Seed

The mystery seeds from last week were from a pine, believe it or not.

pine-seeds

We did a common experiment to see whether open, dry pine cones do indeed close up when placed in water. The seeds floated out of the first cone when we first placed it into the water.

pinecone-wet

And then the pine cone did close up, remarkably quickly.

We looked at another open pine cone.

pine-cone-seed

You can just see tips of the seed wings on the hard pine cone scales. Those wings help them disperse in the wind, like the maple keys they resemble.

pine-cone

Here are pine cones on the ground. What kind of weather have we been having? (Hint: see above.)

pine-branch

Pine cones are often seen hanging on the tree. It takes at least nine months for the seeds to mature within the female cones. Some species require up to two years for the seeds to mature.

Even once the seeds are mature, certain types of pine cones remain closed until they are exposed to the intense heat of a fire.

The seed itself is within the winged structure. If you were to remove the coating, it would look like a pine nut:

pine-nuts

Although the tree associated with the Sonoran desert is usually the saguaro cactus, there are a few pine trees that are planted in urban areas. Two pines that can grow in hot dry conditions are the Mondel or Afghan pine, Pinus eldarica, and the Aleppo pine, Pinus halepensis. They are not native North America, but to regions around the Mediterranean.

What kind of pine trees grow where you live? Have you ever seen a pine seed?

Related activities:

Fibonacci numbers in pine cones

Have you ever tried a pine nut? Look for some in you grocery store and give them a try.

Meet a Scientist Monday: L’Oreal Women in Science Booklet

Between work and everything, I have a short Meet a Scientist Monday today. In order to inform and educate young, budding scientists about their options, L’Oréal-UNESCO has produced a free, downloadable booklet of real stories of young women and their science careers. It is available in .pdf format or online (look under L’Oréal-UNESCO Women in Science in the middle right sidebar).

I hope the stories of these diverse young women scientists are an inspiration.

Weekend Science Fun: Sea Slug Color

Have you ever thought about sea slugs and why they are different colors? It turns out color can be pretty important in sea slugs.

One sea slug, (Elysia chlorotica), is green. Recently scientists investigated the color and found out that the sea slug makes its own food with chlorophyll! Chlorophyll, as you probably know, is the pigment plants use to make their food via photosynthesis. This sea slug not only borrows chloroplasts from the algae it eats, but also can make its own chlorophyll. It is the first animal to be shown to have that ability. Cool! ( Wired Science has a copy of the original article from ScienceNews. Both sites have ads, but the Wired site is less busy.)

Here’s a video that shows the sea slug eating algae. (The video is silent.)

This video from National Geographic shows other, more colorful sea slugs (nudibranchs). (You’ll have to close a pop-up ad.)

Why are these sea slugs so bright? The colors are to warn predators that they aren’t good to eat.

Activities:

1. Draw and color your own sea slug.View images of sea slugs by searching images online, or look for photos in books to help you. Research a particular sea slug. Find out where it lives, what its habitat is like and what it eats.

Tidepool Coloring Book has a drawing of a nudibranch you could use, as well as images of other tidepool creatures.

2. Writing Prompt:

Imagine what our world would be like if more animals could make their own food from sunlight. Imagine green cows or elephants. Now, write a story about it.

Related Activities:
Fieldwork has extensive lesson plans for a high school level marine biology/oceanography class. For example, here’s the lesson on Mollusca/beaches. The author recommends that you have access to a body of salt water to be able to do the hands on activities. Check out the “busy fieldworkers.” Now, that’s my idea of learning.

Tide Pool Invertebrates post from last summer

Thanks to Carl for the heads up about the green sea slug and Susan for leading me to the Fieldwork site.

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