DEFINITION OF SEED

Definition of Seed is the specialized part of a plant that produces a new plant. It contains an embryo (partly developed plant) that consists of an immature root and stem. A seed also has a supply of stored food and a protective covering.

Seeds are produced by approximately 250,000 kinds of plants. Flowering plants make up the largest group of seed-producing plants. These plants, which botanists call angiosperms, include the vast majority of trees, shrubs, and soft-stemmed plants. Seeds are also produced by about 800 kinds of trees and shrubs called gymnosperms. Most gymnosperms develop cones.

The seeds of different kinds of plants vary greatly in size. The double coconut tree produces the largest seed, which weighs up to 50 pounds (23 kilograms). On the other hand, orchid seeds are so tiny that 800,000 of them weigh no more than an ounce (28 grams). The size of a seed has no relationship to the size of the plant that develops from it. For example, the giant redwood tree grows from a seed only 1/16 inch (1.6 millimeters) long.

The number of seeds produced by an individual plant varies according to the size of the seeds. A coconut tree has only a few large seeds, but an orchid or pigweed plant produces millions of tiny ones.

DEFINITION OF ADAPTATION

Definition of Adaptation is a characteristic of an organism that makes it better able to survive and reproduce in its environment. No two organisms of the same species are exactly alike. Every trait, such as size, color, and personality, shows some variation. Additionally, in nature, organisms produce more offspring than can survive. The offspring most likely to survive and reproduce are those with adaptations best suited to the environment. Offspring with variations less suited to the environment do not compete as successfully for food, water, and other necessities. This process of competition, by which those best adapted are most likely to survive and reproduce is called natural selection.

Some forms of life are adapted to living in many different environments. For example, people live in all kinds of climates, ranging from the tropics to the Arctic. Thus, human beings are generalized-that is, the human body has adaptations that enable people to live in widely different environments. But such organisms as mosquitoes and bamboo plants are more specialized. Because of their physical makeup, they can live only in a rather warm, wet climate.

Living things often die when they cannot adapt to a changing environment. Many kinds of plants and animals that once lived on the earth have become extinct. For example, millions of years ago, dinosaurs roamed the earth. But the environment in which they lived changed. The dinosaurs failed to adapt, and they died out.

The word adaptation also refers to the ability of living things to adjust to varying conditions in their environment. If people move to the mountains, their bodies adapt to the lower oxygen supply at high altitudes by making more oxygen-carrying red blood cells. A dog adapts to warm weather by shedding its hair. Adaptations that occur over a relatively short time, particularly because of changes in climate, are often called acclimatizations.

ROOTS OF PLANTS

The definition and understanding of the roots of plants are part of plants that are below ground level and is a very important for plants because it functions not only as a buffer and a founding upright stems but also for absorption of water and nutrients.

In the cultivation of forest treatments silviculture should be based on the properties of the roots, because the studies related to the rooting is not an easy thing to do.

The properties of the roots of the trees varies from type to type, from individual to individual in the same type, and even on different roots in the same individual. Root growth extends laterally commonly associated with growing conditions, while the direction of root growth is influenced by the genetic traits.

The point of view of silviculture , the dynamics of the roots is very important due to the absorption of water and nutrients depends on the ability of roots to grow. In the process of germination, root principal emerged and elongated rapidly, as supply of energy and nutrients in the seeds.
 
Furthermore, the growth rate decreased root and depending on soil conditions. Root development is closely related to soil fertility, the more fertile the soil, the better development of roots.

 

DEFINITION OF ENVIRONMENTAL POLLUTION

Definition of environmental pollution is the inclusion of the organism, energy substances, and or other components into the environment or change the order of the environment by human activities or natural processes so that environmental quality decreases to a certain level cause the environment to be less or cease to function as intended. Pollution may arise as a result of human activities or due to natural (eg volcanic eruption, toxic gases).

Environmental science usually discuss pollution caused by human activities, which can be prevented and controlled. Due to human activities, environmental pollution  inevitable. Environmental pollution can not be avoided. What you can do is to reduce pollution, pollution control, and increasing public awareness and concern for the environment so as not to contaminate lingkngan. Substances or materials that could cause pollution called pollutants. The terms of a substance called a pollutant if its existence could cause harm to a living creature. For example, the carbon dioxide content of 0.033% in air beneficial for the plant, but if it is higher than 0.033% can give damaging effects.
A substance can be called a pollutant if:

1. Excess of the normal.
2. Being on time is not right.
3. Being in the wrong place.

The characteristic of pollutants are:

1. Damaging for a while, but when it reacts with another substance does not damage the environment.
2. Damaging in a long time. For example, Pb does not damage when low concentrations. However, in the long term, Pb can accumulate in the body to damaging levels.

Pollution on the environment, it can be divided into

• air pollution ,
• water pollution, and
• soil pollution.

DEFINITON OF LEGUME

Definition of Legume is any of the plants that belong to the pea family. They make up the second largest family of flowering plants. The composite family is the largest. Botanists recognize between 14,000 and 17,000 species (kinds) of legumes. The group gets its name from the legumes (seed pods) that the plants bear.

Many legumes are of great economic importance throughout the world. Such legumes as peas, beans, and peanuts are valuable foods. Alfalfa, clover, and vetch are important forage and pasture plants. Other legumes yield medicines, dyes, oils, and timber.

Legumes grow in most parts of the world. They vary widely and may be trees, shrubs, or herbs. Many are climbing plants. The flowers of one large subfamily of legumes look like butterflies. Botanists call this group Papilionoideae, from the Latin word for butterfly. The common sweet pea belongs to this group. The flowers of other legumes may be small and regular. The flowers of still others may be irregular, with spreading petals.

Legumes take nitrogen into their roots from the air. Certain bacteria, called rhizobia, live in nodules (knotlike growths) that form along the roots of the plants. These bacteria take nitrogen from the air and change it into forms that can be used by plants. This characteristic makes leguminous plants valuable in agriculture. Farmers often use them as green manure and as cover crops to improve poor soil.

NITROGEN CYCLE | The circulation of nitrogen among the atmosphere

Nitrogen cycle is the circulation of nitrogen among the atmosphere, the soil and water, and the plants and animals of the earth. All living things require nitrogen, but most organisms cannot use the nitrogen gas that makes up about 78 percent of the atmosphere. They need nitrogen that has combined with certain other elements to form organic compounds. But the supply of this fixed nitrogen is limited, so complex methods of recycling nitrogen have developed in nature.

One part of the nitrogen cycle involves circulation of nitrogen between the soil and living things. After plants and animals die, they undergo decomposition by certain bacteria and fungi. These microorganisms produce ammonia from nitrogen compounds in dead organic matter and in body wastes excreted by animals. Plants absorb some of the ammonia and use it to make proteins and other substances essential to life. The rest of the ammonia is changed into nitrates by nitrifying bacteria. First, nitrifying bacteria called nitrite bacteria convert ammonia into nitrites. Then nitrate bacteria change nitrites into nitrates. Plants absorb most of the nitrates and use them in the same way as ammonia. Animals get nitrogen by eating plants or by feeding on animals that eat plants.

In another part of the cycle, a process called nitrogen fixation constantly puts additional nitrogen into biological circulation. In this process, nitrogen-fixing bacteria in the soil or water, or living within plants such as legumes, convert nitrogen from the atmosphere into nitrogen-containing organic substances.

While nitrogen fixation converts nitrogen from the atmosphere into organic compounds, a series of processes called denitrification returns an approximately equal amount of nitrogen to the atmosphere. Denitrifying bacteria convert nitrates and nitrites in soil into nitrogen gas or into gaseous compounds such as nitrous oxide or nitric oxide. However, fixed nitrogen may circulate many times between organisms and the soil before denitrification returns it to the atmosphere.

Some human activities influence the nitrogen cycle. Industry fixes vast quantities of nitrogen to produce fertilizer, much of which is washed off farmland and into waterways, polluting the water. The combustion of certain fuels produces nitrogen compounds that pollute the air. These compounds may also play a part in the warming of the earth's climate

THE BENEFITS OF AN ECOSYSTEM-BASED APPROACH

These landscape and stand level examples, illustrating the functions of some important forest composition and structures, indicate why practices such as clearcutting and elimination of old growth forests are not consistent with maintaining fully functioning forests. If the degradation caused by clearcutting and removal of old growth forests were more evident, people might be more willing to adopt ecologically responsible approaches to timber management.

However, because forests operate on such long timeframes, and because, for millennia, forests have been building biological legacies through many generations of trees that have lived and died, human activities that remove composition and structures do not immediately appear to be as damaging as they actually are. However, as timber managers continue to degrade composition and structures of forests, from landscape to stand levels, damage to forest functioning becomes cumulative. Eventually this approach leads to degraded ecosystems, which provide few ecological functions, compared to the fully functioning forests they replaced. Because forest degradation occurs relatively slowly, successive generations of human beings inherit degraded forests which they assume to be natural, “healthy” ecosystems. In other words, we don’t live long enough to see the results of our mistakes.

An ecosystem-based approach attempts to avoid loss of forest functioning by maintaining forest composition and structures from the smallest soil bacteria to the landscape patterns of a large forest watershed. We may not understand the functions of particular forest composition and structures; nevertheless, an ecologically responsible approach protects all composition and structures. When parts of the forest are altered during activities such as ecologically responsible timber management or tourism, provisions for the replacement of forest composition and structures are built into ecologically responsible plans and activities.

As well as providing for the protection and maintenance of forest functioning, an ecosystem-based approach fosters the development of diverse, sustainable human economies. Because an ecosystem-based approach creates the least modification to forest ecosystem composition and structures, it provides for the largest diversity of compatible forest uses. In other words, by maintaining trees on the sites where we practice timber management and by ensuring that ecologically viable old growth stands are found in each landscape, we provide an environment where the broadest spectrum of uses, from adventure tourism to timber extraction, can coexist. Such a range of activities is not possible where conventional timber management systems, such as clearcuts and tree plantations, are employed.

From a timber standpoint, because ecologically responsible timber management produces steady supplies of mature wood, the long-term economic benefits exceed those of conventional timber management practices. Mature wood—long-fibred and strong—is superior for many uses, from structural materials and pulp to furniture and fine cabinets. In comparison, short-fibred, juvenile wood is not as strong and will warp and twist easily. Mature wood is produced when the cambium layer (the single layer of cells between the wood and the bark) divides around dead branches or no branches. Obviously, increasing amounts of mature wood are produced as a tree gets larger and older.