Tag: plants

Posted on

Biomass on Earth Measured

Biomass on Earth Mostly Plants
Biomass is the mass of living biological organisms. If you lumped all living things by category, what group of organisms do you think would have the greatest biomass on Earth? We aren’t talking about the number of individuals, but the mass of the different lifeforms.

The Proceedings of the National Academy of Sciences on May 21 published a study of the different areas of the world and what form of life dominates in those areas. (Click Here to read the full report.) Plants contribute the primary biomass in the terrestrial environment. Animals are primary in the marine environment. Bacteria and archaea (single-celled microorganisms) dominate the deep subsurface environment.

You may find the results surprising. The total biomass of Earth consists of 80% plants. Bacteria make up the second largest biomass at 15%. After that in descending order are fungi, archaea, protists (unicellular organisms that sometimes form colonies), animals (including humans), and viruses. Soil fungi, protists, soil archaea, arthropods, annelids, and livestock all exceed humans in their biomass. Only wild mammals, nematodes, and wild birds have smaller biomasses than humans. In the marine environment the biomass is much smaller than on land, and after animals, the greatest biomass is in protists, archaea, fungi, and finally bacteria. It is interesting that tiny Antarctic krill contribute about the same biomass as humans.

As you think about the biomass on Earth, it becomes evident that for human life to exist, we need a huge biomass of supporting life-forms. It becomes apparent that we must take care of all of the living things that support us. It is also obvious that before human life could exist on Earth enormous preparation was required.

We have to be reminded of the words of the psalmist in Psalms 8: “When I consider your heavens, the work of your fingers, the moon, the stars, which you have set in place, what is man that you are mindful of him, the son of man that you care for him… You have made him ruler over the works of your hands; you put everything under his feet: all flocks and herds, and the beast of the field, the birds of the air, and the fish of the sea, all that swim the paths of the sea.”
–John N. Clayton and Roland Earnst © 2018

Reference: Scientific American, August 2018, page 16.

Posted on

Why Plants Grow Up

Why Plants Grow Up
Have you ever wondered why plants grow up instead of down? Take a bean, a grain of corn, or any other seed and lay it on top of wet soil until it germinates. The root will grow out of the seed and turn downward into the soil. The shoot will go upward. It doesn’t matter which direction you position the seed when it germinates. Even if the seed germinates in a place where there is no light, the root still goes down, and the stem goes up.

After the root and stem are growing, take the seed and turn it upside down with the root pointing straight up. The root will turn around and head back down into the soil. Take a potted plant and lay it on its side so that it’s horizontal. If the dirt doesn’t fall out, the plant will make a turn and go upward and its roots downward.

Trees on a hillside don’t grow perpendicular to the slope. They grow upward, and the roots grow downward. If there is a landslide and the tree is left horizontal, it will turn and start growing upward again. Amazing, isn’t it?

This ability of plants to know up from down is called gravitropism. Only in recent years has science begun to learn the secrets of how it works. In the cells of the plant, there are particles called statoliths. They normally sit on the bottom of gravity sensing cells. When the plant is tipped, they move and send a message to the growth regulating cells that the direction of gravity has changed. The roots react positively and go toward the source of gravity. The stem responds negatively and goes in the opposite direction.

This explanation is an oversimplified description of why plants grow up. How a plant with no brain or central nervous system communicates the message of which way to grow from one cell to another is still not fully understood. Little by little, science is uncovering the mysteries of life. We still have much to learn, but it’s obvious that plants show evidence of design by a Master Engineer.
–Roland Earnst © 2018