Wednesday, March 18, 2020

Living and Non-Living Cells and Tissues in Trees

Living and Non-Living Cells and Tissues in Trees Only 1 percent of a dormant mature tree is biologically living while the rest is composed of non-living, structural wood cells. In other words, very little of a trees  woody volume is composed of living, metabolizing tissue; rather, the major living and growing portions of a tree are leaves, buds, roots, and a thin film or skin of cells just under the bark called the cambium. There are other living cells that are important for tree growth within the different parts of trees, especially in root tips, the apical meristem, and leaf and flower buds; however, these living cells make up a very small percentage of the total volume of a trees cells. Instead, non-living or dead cells comprise most of the volume of a tree, providing vital structural support for the living cells. Interestingly enough, trees start out in life as a germinating seed with every living cell in hyperdrive, but  as a tree seed becomes a seedling, then a sapling, then a mature tree, its living contents become less and less as a percentage of the total volume. Trees increasingly lose their living cytoplasmic cells as metabolism ceases in each cell, and although they are no longer alive, these non-living cells now provide protection, transportation, and physical support for the living ones. The Vital Role of Non-Living Cells Without the support and structure provided by non-living cells,  trees would likely die  and certainly wouldnt grow quite as large as they do. This is because non-living cells provide a vital role in the process of  how a tree grows  - from the heavy lifting of holding up the tall branches to the trees bark, which protects the thin layer of living cells underneath. This supporting and protective wood is created by cambial-hardened cells produced on the inner and outer cambial layer and sandwiched between the outer cambial layer. As a result, the bark of a tree is a product of the ongoing process of creating  sieve tubes to transport water and nutrients from the leaves to the roots and back. The sound, non-living cells of a tree are very important to helping a tree stay protected, and the bark and structural cells serve as a line of defense against insects and disease that could affect the vulnerable living tissue of the cambium that maintains life throughout the tree. New cells are formed and living cells cease metabolization as they transform into transport vessels and protective skin, creating a cycle of creation, rapid growth, slowing metabolism, and death as the tree climbs ever-higher into a healthy, full plant. When Wood Is Considered Alive and Dead For most intents and purposes, wood is considered to be the product of living cells in trees harnessing the environment around them to make proteins and form protective vessels and shells for the trees sustained growth. Wood is only technically considered dead when its separated from the tree itself, as it still serves a vital role in the plants life when attached to living cells in the tree. In other words, although wood is largely made of non-living cells - cells that no longer reproduce but instead transport nutrients to living cells - it is still considered alive if it is attached to the tree itself. However, if a branch falls off or a person cuts down a tree, the wood is considered dead because it no longer transports living matter through itself. As a result, wood that has been separated from a tree will dry up as the protoplasm hardens and the protein turns into the wood one might use in a fireplace or for building a shelf. This wood is considered dead, though the piece it was once attached to - if still attached to the tree itself - is still considered alive.

Sunday, March 1, 2020

Talking About Young People

Talking About Young People Talking About Young People Talking About Young People By Maeve Maddox Many terms exist to describe children of various ages, all of them having different connotations. The messages of journalists, politicians, merchants, professional educators, and social commentators are often slanted by the terms they choose to describe children. For example, politicians who may usually refer to children as kids are careful to use the words child and children in their important speeches. Apparently, child evokes a more tender response in the listener than kid. Professional educators, who once distinguished between the words pupil and student, now refer to all school children as students. Any word that describes a child is going to carry some emotional charge, but some are more heavily weighted than others. Here are some fairly neutral words to describe young people under the age of 21: baby infant toddler child boy girl youngster juvenile adolescent minor The following words convey more specific images and appeal to different emotions: tot tyke little one preschooler teenager teen preteen student young man young lady young adult waif urchin brat rug rat guttersnipe In the past, the word youth was a useful term often seen in news stories with the meaning of â€Å"a young man between boyhood and mature age.† For example, â€Å"Youth Robs Liquor Store.† Recently, I’ve seen the word used to describe a three-year-old who drowned. Finally, there’s the word kid. As a word for the young of a goat, kid has been in the language at least since 1562; possibly since 1200. The OED documents kid, â€Å"a child, especially a young child,† from the 17th century, noting that it originated as â€Å"low slang,† but by the 19th century had become common in familiar speech. Nowadays, kid is used in the most formal contexts, from the speech and writing of professional educators to the naming of children’s clinics. The word’s elevation to the status of an acceptable synonym for child may have something to do with its similarity to German Kind (child); after all, English is a Germanic language. However, despite its ubiquity as a generic term for child, the word kid can carry negative connotations that prevent it from being acceptable in every context. Related post: â€Å"I Hate ‘Kids† Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Vocabulary category, check our popular posts, or choose a related post below:How Many Tenses in English?Anyone vs. EveryoneHow Long Should a Synopsis Be?