Archive for the ‘education’ Category

How do seeds know when to grow?

November 5, 2010

Joe asks:

why are seeds able to wait for the proper condition to germinate?

Because that’s what seeds do.  Really. Now, HOW they do it, that’s a whole different question…..

Without getting into some fairly complex biochemistry, the answer is fairly simple. Seeds have a whole slew of little biological switches. They are turned on and off depending on the environment that the seed is exposed to. Some of them are fairly simple. For example, if it is very dry, the seed’s shell will stay hard, and keep what moisture there is inside the seed where it belongs – inside the seed. If the outer environment gets wetter, the seed shell will absorb some of the water and get softer. This is actually lot more complex than just soaking up water – the proteins and lipids in the shell actually change shape and go through a bunch of other changes as they absorb the water.

These changes do all sorts of things. When they change shapes, they expose different parts of the proteins to the inside of the seed. When this happens, the newly exposed parts can trigger other reactions inside the seed. Those changes trigger other changes, and if conditions are right, the seed may start to grow.

This is a very simplistic example – all we are looking at is the amount of water int he environment. Temperature, light, nutrients, and a whole slew of other factors can come into play, but the basic concept is the same. If all of these “switches” ‘turn on” (or off) in the right combinations, and in the right sequence, the seed will start to grow.

Sometimes, a seed can “turn on”, then if conditions don’t stay right, they can “turn off” again until conditions get better, but not always. Of course, the longer the seed has been growing, the less likely it will be to be able to return to being dormant. Some seeds are really incredibly good at waiting for the right conditions. A few years ago, a 2,000 year old date palm seed was successfully sprouted, and is still growing. Pretty cool by my book…..

So there ya go. Seeds are basically little environment computers waiting for conditions to be just right  before they launch their “grow” application.

See, science isn’t all that hard if you ask the right questions……

On creationism, intelligent design and evolution

June 30, 2009

OK folks, Dr. science has had it up to here with the Holy Roller Crowd. Its simple: evolution is science. Creationism and intelligent design are religion. Or fantasy, depending on your outlook.

The church and its minions can spew all the misinformation that they want, and may be able to force through laws claiming that their fantasies are “science”, but it won’t make a bit of difference to the FACTS. Evolution is a FACT. If you choose to pretend it isn’t, that is your choice, but it won’t make you right (although it will make you look stupid to anyone with a basic education).

Oh yeah, and the Earth isn’t flat either. Just to clear that up….

Jeez people. Get a clue.

Ask Dr. Science. He knows more than you do.

September 5, 2007

Hey all. Time for a great new Blog service. Yep. I’m going to put that 15 years of graduate school to work for you. Got a question about something in the sciences or technology? shoot me a question (submit a comment), and I’ll apply all that great academic knowledge and ivory tower experience to answer your question. Remember: We’re trained professionals. Don’t try this at home. Objects in mirror are closer than they appear. Time to get another Timmy.
So whadaya waiting for? Send me a question already!

–Dr. Science