Posted on 12/01/2009 6:39:06 PM PST by GodGunsGuts
What I’m impressed with is the genius of Nachmanides. The conclusions he arrived at from the reading of Genesis are pretty impressive.
Kind of throws a wet blanket on those who claim that the Bible is not relevant, or is not accurate scientifically, or can’t be used as a science text.
The evos have been strangely silent on that whole article. I can’t find one who seems to have read it through and given it careful consideration, or is willing to discuss the ramifications.
I think it answers a lot of questions and ties a lot together that otherwise is left hanging.
I don't think that's correct. My understanding, at least, is that the gravity cue is far stronger than the light cue, such that a plant will turn away from sunlight to follow gravity. If you think about it, this almost has to be the case, as there are many instances when a plant has to grow without any direct sunlight, e.g. when shaded in the understory, or before the new shoots break ground.
I recall learning that geotropism exerts the stronger influence that phototropism.
I’d put my money on geotropism first.
Plants can detect “up” by sensory cilia at the “bottom” of a cell getting disturbed by pellets that settle out of the cytoplasm.
Geotropism is essential for the young spout to grow UP out of the soil.
Once up out of the soil, a plant uses heliotropism to turn its leaves towards the Sun. It doesn't grow towards the sun, as much as it turns towards the sun; because where the sun is changes during the day. Heliotropism is accomplished by swelling tissues with water, while evacuating other tissue of water- causing the stem to twist, turning the leaves towards the sun; facing East in the morning and west in the evening.
I have watched over a period of months, a set of vines take off horizontally, then up a hill, then directly to an abandoned car bumper, and wrap themselves around it.
Is it because the car bumper is an extreme source of gravity?
I understand what you are saying, however I think it odd the way you say it.
“It doesn’t grow towards the sun, as much as it turns towards the sun; because where the sun is changes during the day.”
That is like saying that if I am trying to get my sailboat back to port, and I have to tack to keep on course, I’m not really heading to port.
Thanks for the example. When shaded in the understory, many plants and trees will grow horizontally to get out from under a larger plant. Or, out from under a ledge.
A question. Why do you think it is important that certain seeds be planted at certain depths?
(Hint: It has nothing to do with gravity)
Sorry to be bothersome, but another question rears it’s head.
Why do roots grow downward? Is this caused by gravity as well?
Heliotropism isn't the plant growing towards the Sun (which direction is towards the Sun?); it is the plant turning its leaves towards the Sun.
Even if the plant isn't growing, they will still display heliotropism; facing East in the morning and West in the evening.
As far as a vine growing over a car, that is what vines do. They grow over things and “rob” them of their sunlight; luckily for the car it doesn't need sunlight.
Cf. dinosaurs.
A seed must be planted at a depth where it can successfully take root, but not so deep that it will exhaust the energy of its endosperm before starting to gain energy through photosynthesis.
Generally I take the advice of the farmers almanac or the seed pack when planting. I am an experimental scientist but I have little interest in conducting an experiment on proper seed planting depth. I just want good produce and follow the advice of those who have done it before and hopefully received good results.
What factors do YOU see influencing how deep to plant a seed?
And yet, in reality, a plant will ignore gravity, to follow the sunlight.
You can do this test yourself, at home.
Set up a plant so that the only source of light comes from below the level of the planter.
So, if I am driving down the street, and I turn the steering wheel, which turns the front tires in that direction, you are telling me that I won't actually turn left, but my tires will be facing it as I go by?
I apparently didn't communicate well. The vines grew straight towards the car bumper, from 40 feet away, and wrapped themselves around the bumper. They followed the top of the ground, until they got a few feet away, then started growing at an approaching angle, until they get exactly to the bumper. They did not go any further. They simply spiraled themselves around that bumper.
Is it towards the Sun at morning, evening or midday?
What direction is “towards the Sun”?
Heliotropism is the turning of the leaves, like little solar panels, so that they are perpendicular to the incoming sunlight. This is caused by hydraulic pressure in the stems.
A sunflower faces east in the morning and west in the evening; which direction is it growing?
From Wiki....
Heliotropism is the diurnal motion of plant parts (flowers or leaves) in response to the direction of the sun.
Heliotropism was first described by Leonardo da Vinci (along with gravitropism) in his botanical studies. The term “heliotropism,” though, was introduced in the early 1800s by A. P. de Candolle, for the growth of the stem tip towards light, which is now called phototropism. The term heliotropism is now used only for solar tracking.
Assuming you meant, learned it in school, in your younger years, let me ask you this:
Were they correct? You were also told that the Universe was infinite (I assume), then you were told it was Finite (after discovery of the big bang wave). Which is true?
We are arguing that scientists of the past may have been misinformed ( like, say, Darwin) and yet you stick to a teaching that may be just as untrue.
Matter of fact, if you look at nature around you, you will see that the Sun is the main force of growth, and that gravity more likely plays only a tiny little part in a plant 'figuring' out which way to grow.
What I'm saying is that if one wants to imply that plants 'understand' and 'use' gravity, (pretty intelligent thing, I'd say), then OK. But, they also know if they don't follow, or grow towards the Sun, they will die.
Towards nutrients, including water. They are actually darn good at finding water. They will break through metal pipes just to get to water.
I would say you don't need to look it up, as it is fairly obvious. You understand it completely.
The problem I had with your response earlier is that you don't see turning towards the Sun the same as growing towards the Sun.
What causes a seed to actually sprout?
(Hint: again, it's not gravity)
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