Monday, May 16, 2016

ATI Wisdom Booklet 5: Science - How Wheat Grows

In today's little slice of crazy from ATI's Wisdom Booklet 5, we take John 12:24 and use it as the basis for an entire lesson on how plants grow from seeds.  Teaching kids how plants grow is a great idea!  Using John 12:24 as a literal explanation of how wheat grows is a terrible idea.

I don't want anyone to think I'm bashing the Bible.  I love the metaphor in this verse about how death or loss often brings new life.  I've been humming the hymn "Unless A Grain of Wheat" all day.  Historically, the metaphor makes sense.  In areas of the world with seasonal dry spells - either hot times without rain or cold times where water is frozen - it seems like seeds have to go through a "dead" spell where they are dried out before they can germinate.

The problem comes is that the seeds that germinate are not dead during the dry time.  They are dormant.  This would have been impossible to see during the time of the Bible, but we are well aware of it now.

  • How does a grain of wheat illustrate the principle of meekness?  Well, the best answer I have so far is "A grain of wheat does not illustrate meekness."
  • Notice that Gothard defines meekness in a way that I've never heard of before. defines meekness as "humbly patient or docile as under provocation from others" or "gentle and kind" in obslete meaning.

  • I take these questions as a pretest.
  1. Meekness isn't a fruit, but wheat is a fruit because it is the mature ovary and seeds of a plant.
  2. The grain of wheat must detach from the parent plant which is sort of like a form of death....kind of....
  3. Um....pride?  Generalized crabbiness? Is this a science questions?
  4. Wheat has five stages: embryo, seedling, mature arrangement...ugh..and chaff?  (Ok, it has three stages).  Meekness clearly follows the same pattern because it makes a great floral arrangement.
  •  A small part of me died because I read that paragraph.  I am a botanist by training.  I love plants and I adore plant classification.  Absolutely nothing in the first two paragraphs is correct.
    • The wheat grains we eat are fruits because the botanical definition of a fruit is the mature ovary and associated seeds found in flowering plants. This is known as the botanical definition.
      • If you want to go all full-frontal nerdy, the fruits of plants in the Grass Family (Poaceae) are known as a caryopsis or multiple caryopses.
    • All seed-bearing plants HAVE fruits, not ARE fruits.  For example, the stalk of a corn plant, the trunk of an oak tree and the leaves of an apples tree are not fruits; the corn grain, acorn and apple are fruits.
    • In addition to the botanical definition, there is the culinary definition of fruits and vegetables.  Tomatoes, squash and string beans are fruits in the botanical definition and vegetables in the culinary definition.  
    • Not every culinary vegetable is a fruit.  All of the cabbage family members (cabbage, kale, brussel sprouts, broccoli, cauliflower, rutabaga), all of the root vegetables (carrots, parsnips, turnips, beets etc.) and all of the greens (lettuce, collards, spinach, Swiss chard, mustard etc.) are vegetative parts of the plant in the botanical sense and vegetables in the culinary sense.
    • Vegetables are not all annual plants.  Asparagus is an perennial plant that is a vegetable.  Jerusalem artichokes and potatoes are also perennials that are vegetables.
    • Fruits are not all perennial plants.  Ground cherries need to be replanted yearly.
    • Don't refer to anything as a "vegetable fruit".  Those are two different classes in both the botanical and culinary naming systems.

  • Good news!  There is a tiny plant in each wheat grain.
  • Bad news!  The husk doesn't have to split for water to enter.  The husk will allow water from the soil though.
  • Bad news!  Germination is the entire process of the seed going from a dormant state until it reaches the first true leaves.

  • I wonder how many authors worked on this section.  This paragraph has a better description of what happens to the seed coat over time.  It also contradicts the previous paragraph.
  • Yikes.  "A seed requires large amounts of oxygen because it cannot produce its own food" is both confusing and not right at all.  
    • A seed needs oxygen to grow as do most living organisms.  Oxygen is used by cells to break down sugar or starch and capture the energy stored in the starch.  In seeds, the embryo starts developing by breaking down carbohydrates, fats or proteins that have been stored in the seed for this exact purpose.
    • A seed cannot produce its own food from photosynthesis because the required structures like leaves are not exposed to the sun while the embryo is in the seed or buried under soil.
    • Making food in plants does not require oxygen!  Photosynthesis requires water, sunlight and carbon dioxide.  Inside the cells of the plant, the atoms in the water and carbon dioxide are rearranged to form sugar molecules which store the energy captured from sunlight.
  • Minimum germination temperature do exist and are quite important.  The problem is that abundant water below the germination temperature can lead to the seed rotting before germination is completed.

  • Everything in the section above is correct.  What confuses me is WHY this information is placed here.  The last section left off with a seed spitting out of the seed coat and using up the stored energy in the seed.  There is no discussion of the embryonic leaves (cotyledons) or the process by which the embryo figures out how to send the leaves up towards the surface while sending roots downward.

  • How did we transition from roots to grasshoppers?  
  • Grasshoppers and locusts are not a problem for farmers in North America; we managed to extinct the only grasshopper species that formed swarms in the US - known as the Rocky Mountain Locust - and no one is entirely sure how. (The best ideas right now center around destruction of the eggs in the soil as a side-effect of plowing for agricultural land or gold mine digging.)
  • Locust swarms are more problematic in Australia and a major issue in Africa.
  • The Chinch Bug is a minor issue that causes localized grain loss during dry summers in the Northern Mississippi River basin.  It's such a minor issues that the local extension agencies don't recommend spraying for it unless the infestation is really dense.

  • You know, if I was going to focus on a single wheat disease, I'd pick common smut since it can cause spontaneous ignition of the fields....
  • Hessian flies are a real economic issue.  The problem isn't with the flies or the larva drinking the liquid in the wheat exactly.  The problem is that the larva weaken the stem so much that the stem breaks before the grains on the wheat have ripened.   

  • Again, the ATI authors make the mistake of painting with too broad of brush strokes.  Seeds don't have to separate from the parent plant to germinate.  Mangrove seeds always germinate on the parent tree.  If you wander around in the Eastern deciduous forests in Michigan, it's possible to find tree seedlings that have sprouted in the crotches of branches.  
    • Having said that, it is beneficial for most seeds to get away from their parent plant.  The reason is two-fold - and the basis of evolution.  
    • First, the parent plant is using the sunlight, water and nutrients in that space.  If a seed germinates under its parent, the seedling will most likely be unable to compete and die.  
      • Second,  once a plant puts down roots, it is pretty much stuck in place for life.  The only time a plant can travel to a new territory is as a seed.
  • Not all seeds need to dehydrate.  First of all, seeds that are native to climates where water is abundant like tropical rainforests don't handle drought well.  Even many temperate plants can germinate directly from undehydrated seeds.  
    • The tricky bit for temperate climate seeds is actually exposure to a minimum temperature OR a certain number of hours below a given temperature.  Once you know that trick, you can start messing around with some garden plants.  Tulips, for example, need around 6 weeks of freezing temperature before they will grow from the bulb again.  When your tulips finish, you can dig out the bulb, pop it in the freezer for six weeks, and replant it in the garden to get more tulips.
    • Drying is very important if seeds are going to be stored.  In storage, bacteria and mold will destroy the seed if it is not dry enough.
  • The burial section was dead-on until the last sentence.  Plants don't have symbols.  Humans have symbols.  If humans want to use the planting of seeds as a symbol for death, that's great - but traditionally the planting of seed is the symbol of birth, not death.  Harvest is a traditional symbol of death. 
  • Dormancy is not death.  Dormancy is a very low metabolic state that can persist for long periods of time.  Death is the irreversible cessation of metabolic processes.

  • Most plants will throw a root out before trying to send a shoot upward.  The simple reason for this is that water intake is critically important for the vascular tissues of a seedling to survive.  If the plant sent a shoot up first, the shoot would start drawing water up from the seed.  If there is no water available, air enters the vascular tissue.  Air in a plant vascular tissue creates the same damage as a blood clot blocking a blood vessel in a human with one major difference: Humans can sometimes dissolve clots using enzymes in the body while plants have no way of removing the air bubble.   In other words, leaves with no roots = dead plant.  
  • What analogies can I find between wheat and meekness?  None - and that's fine with me.

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