PLANE (TOOL)

A hand plane is a tool for shaping wood. When powered by electricity, the tool may be called a planer. Planes are used to flatten, reduce the thickness of, and impart a smooth surface to a rough piece of lumber or timber. Planing is used to produce horizontal, vertical, or inclined flat surfaces on workpieces usually too large for shaping. Special types of planes are designed to cut joints or decorative mouldings.

A Japanese plane in use.

Hand planes are generally the combination of a cutting edge, such as a sharpened metal plate, attached to a firm body, that when moved over a wood surface, take up relatively uniform shavings, by nature of the body riding on the 'high spots' in the wood, and also by providing a relatively constant angle to the cutting edge, render the planed surface very smooth. A cutter which extends below the bottom surface, or sole, of the plane slices off shavings of wood. A large, flat sole on a plane guides the cutter to remove only the highest parts of an imperfect surface, until, after several passes, the surface is flat and smooth. When used for flattening, bench planes with longer soles are preferred for boards with longer longitudinal dimensions. A longer sole registers against a greater portion of the board's face or edge surface which leads to a more consistently flat surface or straighter edge. Conversely, using a smaller plane allows for more localized low or high spots to remain.

Though most planes are pushed across a piece of wood, holding it with one or both hands, Japanese planes are pulled toward the body, not pushed away.

Woodworking machinery that perform the same function as hand planes include the jointer and the thickness planer, also called a thicknesser. When rough lumber is reduced to dimensional lumber, a large electric motor or internal combustion engine will drive a thickness planer that removes excess wood to create a uniform, smooth surface on all four sides of the lumber and may also plane the edges.

History

Hand planes are ancient, originating thousands of years ago. Early planes were made from wood with a rectangular slot or mortise cut across the center of the body. The cutting blade or iron was held in place with a wooden wedge. The wedge was tapped into the mortise and adjusted with a small mallet, a piece of scrap wood or with the heel of the user's hand. Planes of this type have been found in excavations of old sites as well as drawings of woodworking from medieval Europe and Asia. The earliest known examples of the woodworking plane have been found in Pompeii although other Roman examples have been unearthed in Britain and Germany. The Roman planes resemble modern planes in essential function, most having iron wrapping a wooden core top, bottom, front and rear and an iron blade secured with a wedge. One example found in Cologne has a body made entirely of bronze without a wooden core. A Roman plane iron used for cutting moldings was found in Newstead, England. Histories prior to these examples are not clear although furniture pieces and other woodwork found in Egyptian tombs show surfaces carefully smoothed with some manner of cutting edge or scraping tool. There are suggestions that the earliest planes were simply wooden blocks fastened to the soles of adzes to effect greater control of the cutting action.

A pair of wooden planes found on board the 16th century carrack, Mary Rose.

In the mid-1860s, Leonard Bailey began producing a line of cast iron-bodied hand planes, the patents for which were later purchased by Stanley Rule & Level, now Stanley Works. The original Bailey designs were further evolved and added to by Justus Traut and others at Stanley Rule & Level. The Bailey and Bedrock designs became the basis for most modern metal hand plane designs manufactured today. The Bailey design is still manufactured by Stanley Works.

In 1918 an air-powered handheld planing tool was developed to reduce shipbuilding labor during World War I. The air-driven cutter spun at 8000 to 15000 rpm and allowed one man to do the planing work of fifteen men who used manual tools.

Modern hand planes are made from wood, ductile iron or bronze which produces a tool that is heavier and will not rust.

Parts

Parts of a plane

Two styles of plane are shown with some parts labeled. The top of the image is a bench plane; the bottom is a block plane.

A bench plane iron with chip-breaker.

• A: The mouth is an opening in the bottom of the plane down through which the blade extends, and up through which wood shavings pass.
• B: The iron is a plate of steel with a sharpened edge which cuts the wood. Some people refer to it as the blade.
• C: The lever cap holds the blade down firmly to the body of the plane.
• D: The depth adjustment knob controls how far the blade extends through the mouth.
• E: The knob is a handle on the front of the plane.
• F: The chipbreaker or Cap iron serves to make the blade more rigid and to curl and break apart wood shavings as they pass through the mouth.
• G: The lateral adjustment lever is used to adjust the iron by skewing it so that the depth of cut is uniform across the mouth.
• H: The tote is a handle on the rear of the plane.(Some aficionados object to the use of the word tote preferring handle).
• I: The finger rest knob Block planes are held in the palm of the hand while the tip of the user's index finger rests in the indentation on top of the knob. On some planes the knob is used to adjust the size of the mouth by allowing a sliding portion of the sole to be moved back or forward to accomplish this.
• J: The frog is a sliding iron wedge that holds the plane iron at the proper angle. It slides to adjust the gap between the cutting edge and the front of the mouth. The frog is screwed down to the inside of the sole through two parallel slots and on many planes is only adjustable with a screwdriver when the plane iron is removed. Some planes, such as the Stanley Bedrock line and the bench planes made by Lie-Nielsen and WoodRiver/Woodcraft Have a screw mechanism that allows the frog to be adjusted without removing the blade.
• The sole is the bottom face of the plane that slides against the wood.

Types

Most planes are broadly categorized as either bench planes, block planes, or specialty planes. In modern-day carpentry, electrically powered hand planers (also called hand or handheld power planers or simply power planes) have joined the family.

Modern wooden plane.

Bench planes are characterized by the cutting iron bedded with the bevel facing down and attached to a chipbreaker. Most metal bench planes, and some larger wooden ones, are designed with a rear handle known as a tote. Block planes are characterized by the absence of a chipbreaker and the cutting iron bedded with the bevel up. The block plane is usually a smaller tool that can be held with one hand and is used for general purpose work such as taking down a knot in the wood, smoothing small pieces, chamfering edges, and making the end of a sawed board square and smooth.

Different types of bench planes are designed to perform different tasks, with the name and size of the plane being defined by the use. Bailey iron bench planes were designated by number respective to the length of the plane. This has carried over through the type, regardless of manufacturer. A No. 1 plane is but little more than five inches long. A typical smoothing plane (approx. nine inches) is usually a No. 4, jack planes at about fourteen inches are No. 5, an eighteen inch foreplane will be a No. 6, and the jointer planes at twenty-two to twenty-four inches in length are No. 7 or 8 respectively. A designation, such as No. 4½ indicates a plane of No. 4 length but slightly wider. A designation, such as 5-1/2 indicates the length of a No. 5 but slightly wider (actually, the width of a No. 6 or a No. 7), while a designation, such as 5-1/4 indicates the length of a No. 5 but slightly narrower (actually, the width of a No. 3). "Bedrock" versions of the above are simply 600 added to the base number (although no "601" was ever produced, such plane is indeed available from specialist dealers; 602 through 608, including all the fractionals, were made).

A typical order of use in flattening, truing, and smoothing a rough sawn board might be:

• A scrub plane, which removes large amounts of wood quickly, is typically around 9 inches (230 mm) long, but narrower than a smoothing plane, has an iron with a curved cutting edge, and has a wider mouth opening to accommodate the ejection of thicker shavings/chips.

• A jack plane, is around 14 inches (360 mm) long, continues the job of roughing out, but with more accuracy and flattening capability than the scrub.
• 
  Craftsman No. 5 Jack Plane.
• A jointer plane, (including the smaller fore plane) is between 18 to 24 inches (460 to 610 mm) long, and is used for jointing and final flattening out of boards.
• A smoothing plane, up to 10 inches (250 mm) long, is used to begin preparing the surface for finishing.
• A polishing plane, is a traditional Japanese woodworking tool which takes an even smaller shaving than a western smoothing plane to create an extremely smooth surface. Polishing planes are the same length as western smoothing planes.
• 
  Stanley No. 32 transitional jointer plane (26 inches long).

Planes may also be classified by the material of which they are constructed:

• A wooden plane is entirely wood except for the blade. The iron is held into the plane with a wooden wedge, and is adjusted by striking the plane with a hammer.
• A transitional plane has a wooden body with a metal casting set in it to hold and adjust the blade.
• A metal plane is largely constructed of metal, except, perhaps, for the handles.

• An infill plane has a body of metal filled with very dense and hard wood on which the blade rests and the handles are formed. They are typically of English or Scottish manufacture. They are prized for their ability to smooth difficult grained woods when set very finely.
• 
  A smoothing plane.
• A side-escapement plane, has a tall, narrow, wooden body with an iron held in place by a wedge. They are characterized by the method of shaving ejection. Instead of being expelled from the center of the plane and exiting from the top, these planes have a slit in the side by which the shaving is ejected. On some variations, the slit is accompanied by a circular bevel, cut in the side of the plane which causes the shaving to eject to the side through the open body of the plane.

Some special types of planes include:

Stanley No. 92 Rabbet Plane.

• The rabbet plane, also known as a rebate or openside plane, which cuts rabbets (rebates) i.e. shoulders, or steps.
• The spokeshave, is held horizontally by two symmetrical handles in line with the cutting edge of the iron. It has a very short sole, either flat, concave, or convex and is used for smoothing curved surfaces such as wagon spokes or tool handles.

• The shoulder plane, is characterized by a cutter that is flush with the edges of the plane, allowing trimming right up to the edge of a workpiece. It is commonly used to clean up dadoes (housings) and tenons for joinery.
• 
  Stanley No. 78 Fillister Plane.

• The fillister plane, similar to a rabbet plane, with a fence that registers on the board's edge to cut rabbets with an accurate width.
• The moulding plane which is used to cut mouldings along the edge of a board.
• The grooving plane which is used to cut grooves along the edge of a board for joining. Grooves are the same as dadoes/housings, but are being distinguished by running with the grain.
• 
  Router plane.
• The plow/plough plane, which cuts grooves and dadoes (housings) not in direct contact with the edge of the board.

• The router plane, which cleans up the bottom of recesses such as shallow mortises, grooves, and dadoes (housings). Router planes come in several sizes and can also be pressed into service to thickness the cheeks of tenons so that they are parallel to the face of the board.
• 
  Finger planes. Note the size.
• Router plane.
• The chisel plane, which removes wood up to a perpendicular surface such as from the bottom inside of a box.

• The finger plane,  which is used for smoothing very small pieces such as toy parts, very thin strips of wood, etc. The very small curved bottom varieties are known as violin makers planes and are used in making stringed instruments.
• The bullnose plane, has a very short leading edge to its body, and so can be used in tight spaces; most commonly of the shoulder and rabbet variety. some bullnose planes have a removable toe so that they can pull double duty as a chisel plane.

• The combination plane, which combines the function of moulding and rabbet planes, which has different cutters and adjustments.

Stanley No. 55 Combination Plane.

• The circular or compass plane, which utilizes an adjustment system to control the flex on a steel sheet sole and create a uniform curve. A concave setting permits great control for planing large curves, like table sides or chair arms, and the convex works well for chair arms, legs and backs, and other applications.
• The toothed plane, which is used for smoothing wood with irregular grain. and for preparing stock for traditional hammer veneering applications.
• The spar plane, which is used for smoothing round shapes, like boat masts and chair legs.
• The match plane, which is used for making tongue and groove boards.
• Hollows and Rounds, which are similar to moulding planes, but lack a specific moulding profile. Instead, they cut either a simple concave or convex shape on the face or edge of a board to create a single element of a complex-profile moulding. They are used in pairs or sets of various sizes to create moulding profile elements such as fillets, coves, bullnoses, thumbnails ovolos, ogees, etc. When making mouldings, hollows and rounds must be used together to create the several shapes of the profile. However, they may be used as a single plane to create a simple decorative cove or round-over on the edge of a board. Many of these holes and rounds can be classified in the category of side-escampement planes.

Use

Planing wood along its side grain should result in thin shavings rising above the surface of the wood as the edge of the plane iron is pushed forward, leaving a smooth surface, but sometimes splintering occurs. This is largely a matter of cutting with the grain or against the grain respectively, referring to the side grain of the piece of wood being worked.

Planing with the grain.

The grain direction can be determined by looking at the edge or side of the work piece. Wood fibers can be seen running out to the surface that is being planed. When the fibers meet the work surface it looks like the point of an arrow that indicates the direction. With some very figured and difficult woods, the grain runs in many directions and therefore working against the grain is inevitable. In this case, a very sharp and finely-set blade is required.

When planing against the grain, the wood fibers are lifted by the plane iron, resulting in a jagged finish, called tearout. Planing against the grain in this manner is sometimes called "traverse" or "transverse" planing.

Planing against the grain.

Planing the end grain of the board involves different techniques, and frequently different planes designed for working end grain. Block planes and other bevel-up planes are often effective in planing the difficult nature of end grain. These planes are usually designed to use an iron bedded at a "low angle," typically about 12 degrees.

References

1. ^ C. W. Hampton, E. Clifford: "Planecraft", page 9. C. and J. Hampton Ltd. 1959
2. ^ Henry C. Mercer: "Ancient Carpenters' Tools", page 16. Bucks County Historical Society. 1975
3. ^ Planing Ship Timbers with Little Machines, Popular Science monthly, December 1918, page 68, Scanned by Google Books: http://books.google.com/books?id=EikDAAAAMBAJ&pg=PA68.
4. ^ "Toothed Plane". ECE.
5. ^ "Shaping plane for rounding a spar".
6. ^ "Stanley No. 148 Match Plane".

Bibliography

• Greber, Josef M. (1956 reprinted 1987) Die Geschichte des Hobels von der Steinheit bis zur Enstehung der Holzwerkzeugfabriken im frühen 19. Jahrhundert, Zurich, reprinted Hanover
• Greber, Josef M., transl. by Seth W. Burchard (1991) The History of the Woodworking Plane from the Stone Age to the Development of Woodworking Factories in the Early 19th Century, Albany, NY
• Hack, Garrett (1997) The Handplane Book. ISBN 1-56158-155-0.
• Hoadley, R. Bruce (2000) Understanding Wood: A Craftsman’s Guide to Wood Technology.ISBN 1-56158-358-8.
• Russell, David R., with Robert Lesage and photographs by James Austin, cataloguing assisted by Peter Hackett (2010) Antique Woodworking Tools: Their Craftsmanship from the Earliest Times to the Twentieth Century, Cambridge: John Adamson ISBN 978-1-898565-05-5.
• Salaman, R. A.  (1989) Dictionary of Woodworking Tools. ISBN 0-04-440256-2.
• Todd, R., Allen, D., Alting, L., Manufacturing Processes Reference Guide, p. 124, 1994
• Watson, Aldren A. (1982) Hand Tools: Their Ways and Workings. ISBN 1-55821-224-8.
• Whelan, John M. (1993) The Wooden Plane: Its History, Form and Function Mendham, NJ: Astragal Press ISBN 978-1-879335-32-5.

External Links

• Handplane Central, Information for all types of hand planes, including wooden planes, infill planes and Stanley type planes. Also information on how to make hand planes.
• Catalog of American Patented Antique Tools, A pictorial collection of antique planes and other tools showing some of the variety in styles.
• The history, types, collector value and other information on the British hand plane maker Record Planes.

- Wikipedia 

GENETIC EROSION

Genetic erosion is a process whereby an already limited gene pool of an endangered species of plant or animal diminishes even more when individuals from the surviving population die off without getting a chance to meet and breed with others in their endangered low population. The term is sometimes used in a narrow sense, such as when describing the loss of particular alleles or genes, as well as being used more broadly, as when referring to the loss of varieties or even whole species.

Genetic erosion occurs because each individual organism has many unique genes which get lost when it dies without getting a chance to breed. Low genetic diversity in a population of wild animals and plants leads to a further diminishing gene pool – inbreeding and a weakening immune system can then "fast track" that species towards eventual extinction.

All the endangered species of the world are plagued to varying degrees by genetic erosion, and most need a human-assisted breeding program to keep their population viable, thereby avoiding extinction over long time frames. The smaller the population is on a relative scale, the more magnified the effect of genetic erosion becomes, as weakened individuals from the few surviving members of the species are lost without getting a chance to breed.

Genetic erosion also gets compounded and accelerated by habitat fragmentation - today most endangered species live in smaller and smaller chunks of (fragmented) habitat, interspersed with human settlements and farmland, making it much more difficult to naturally meet and breed with others of their kind, so many die off without getting a chance to breed at all, and thus are unable to pass on their unique genes to the living population.

The gene pool of a species or a population is the complete set of unique alleles that would be found by inspecting the genetic material of every living member of that species or population. A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection. Meanwhile, low genetic diversity (see inbreeding and population bottlenecks) can cause reduced biological fitness and increase the chance of extinction of that species or population.

Processes and consequences

Population bottlenecks create shrinking gene pools, which leave fewer and fewer fertile mating partners. The genetic implications can be illustrated by considering the analogy of a high-stakes poker game with a crooked dealer. Consider that the game begins with a 52-card deck (representing high genetic diversity). Reduction of the number of breeding pairs with unique genes resembles the situation where the dealer deals only the same five cards over and over, producing only a few limited "hands".

As specimens begin to inbreed, both physical and reproductive congenital effects and defects appear more often. Abnormal sperm increase, infertility rises, and birthrates decline. "Most perilous are the effects on the immune defense systems, which become weakened and less and less able to fight off an increasing number of bacterial, viral, fungal, parasitic, and other disease-producing threats. Thus, even if an endangered species in a bottleneck can withstand whatever human development may be eating away at its habitat, it still faces the threat of an epidemic that could be fatal to the entire population."

Loss of agricultural and livestock biodiversity

Genetic erosion in agricultural and livestock is the loss of biological genetic diversity – including the loss of individual genes, and the loss of particular recombinants of genes (or gene complexes) – such as those manifested in locally adapted landraces of domesticated animals or plants that have become adapted to the natural environment in which they originated.

The major driving forces behind genetic erosion in crops are variety replacement, land clearing, overexploitation of species, population pressure, environmental degradation, overgrazing, governmental policy, and changing agricultural systems. The main factor, however, is the replacement of local varieties of domestic plants and animals by other varieties or species that are non-local. A large number of varieties can also often be dramatically reduced when commercial varieties are introduced into traditional farming systems. Many researchers believe that the main problem related to agro-ecosystem management is the general tendency towards genetic and ecological uniformity imposed by the development of modern agriculture.

Prevention by human intervention, modern science and safeguards

In-Sifu conservation

With advances in modern bioscience, several techniques and safeguards have emerged to check the relentless advance of genetic erosion and the resulting acceleration of endangered species towards eventual extinction. However, many of these techniques and safeguards are too expensive yet to be practical, and so the best way to protect species is to protect their habitat and to let them live in it as naturally as possible.

Wildlife sanctuaries and national parks have been created to preserve entire ecosystems with all the web of species native to the area. Wildlife corridors are created to join fragmented habitats (see Habitat fragmentation) to enable endangered species to travel, meet, and breed with others of their kind. Scientific conservation and modern wildlife management techniques, with the expertise of scientifically trained staff, help manage these protected ecosystems and the wildlife found in them. Wild animals are also translocated and reintroduced to other locations physically when fragmented wildlife habitats are too far and isolated to be able to link together via a wildlife corridor, or when local extinctions have already occurred.

Ex-Sifu conservation

Modern policies of zoo associations and zoos around the world have begun putting dramatically increased emphasis on keeping and breeding wild-sourced species and subspecies of animals in their registered endangered species breeding programs. These specimens are intended to have a chance to be reintroduced and survive back in the wild. The main objectives of zoos today have changed, and greater resources are being invested in breeding species and subspecies for then ultimate purpose of assisting conservation efforts in the wild. Zoos do this by maintaining extremely detailed scientific breeding records (i.e. studbooks) and by loaning their wild animals to other zoos around the country (and often globally) for breeding, to safeguard against inbreeding by attempting to maximize genetic diversity however possible.

Costly (and sometimes controversial) ultra-modern ex-situ conservation techniques have emerged that aim to increase the genetic biodiversity on our planet, as well as the diversity in local gene pools, by guarding against genetic erosion. Modern concepts like seedbanks, sperm banks and tissue banks have become much more commonplace and valuable. Sperm, eggs and embryos can now be frozen and kept in banks, which are sometimes called "Modern Noah's Arks" or "Frozen Zoos". Cryopreservation techniques are used to freeze these living materials and keep them alive in perpetuity by storing them submerged in liquid nitrogen tanks at very low temperatures. Thus, preserved materials can then be used for artificial insemination, in vitro fertilization, embryo transfer and cloning methodologies to protect diversity in the gene pool of critically endangered species.

It is today possible to save an endangered species from extinction by preserving only partsof specimens, such as tissues, sperm, eggs, etc. – even after the death of a critically endangered animal, or collected from one found freshly dead, in captivity or from the wild. A new specimen can then be "resurrected" with the help of cloning, so as to give it another chance to breed its genes into the living population of the respective threatened species. Resurrection of dead critically endangered wildlife specimens with the help of cloning is still being perfected, and is still too expensive to be practical, but with time and further advancements in science and methodology it may well become a routine procedure not to far into the future.

Recently, strategies for finding an integrated approach to in situ and ex situ conservation techniques have been given considerable attention, and progress is being made.

References

1. ^ Stephen J. O'Brien, Chief, Laboratory of Viral Carcinogenesis, National Cancer Institute (April 1992). "GENETIC EROSION A Global Dilemma". National Geographic (Posted online by Oslo Cyclotron Laboratory at the Department of Physics, UiO; The University of Oslo in Norway): 136. Retrieved 20 October 2007. A population bottleneck creates a shrinking gene pool that leaves fewer and fewer mating partners. What are the genetic implications? The animals become part of a high stakes poker game – with a crooked dealer. After beginning with a 52-card deck, the players wind up with, say, five cards that they are dealt over and over. As they begin to inbreed, congenital effects appear, both physical and reproductive. Often abnormal sperm increase; infertility rises; the birthrate falls. Most perilous in the long run, each animal's immune defense system is weakened. Thus, even if an endangered species in a bottleneck can withstand whatever human development may be eating away at its habitat, it still faces the threat of an epidemic that could well be fatal to the entire population.
2. ^ See DIVERSEEDS online discussion forum on the integrated approach.

-Wikipedia 

POPULATION MODEL

A population model is a type of mathematical model that is applied to the study of population dynamics.

Models allow a better understanding of how complex interactions and processes work. Modeling of dynamic interactions in nature can provide a manageable way of understanding how numbers change over time or in relation to each other. Ecological population modeling is concerned with the changes in population size and age distribution within a population as a consequence of interactions of organisms with the physical environment, with individuals of their own species, and with organisms of other species (biophysical env.) The world is full of interactions that range from simple to dynamic. Many, if not all, of Earth’s processes affect human life. The Earth’s processes are greatly stochastic and seem chaotic to the naked eye. However, a plethora of patterns can be noticed and are brought forth by using population modeling as a tool. Population models are used to determine maximum harvest for agriculturists, to understand the dynamics of biological invasions, and have numerous environmental conservation implications. Population models are also used to understand the spread of parasites, viruses, and disease. The realization of our dependence on environmental health has created a need to understand the dynamic interactions of the earth’s flora and fauna. Methods in population modeling have greatly improved our understanding of ecology and the natural world.

History

Late 18th-century biologists began to develop techniques in population modeling in order to understand dynamics of growing and shrinking ball populations of living organisms. Thomas Malthus was one of the first to note that populations grew with a geometric pattern while contemplating the fate of humankind. One of the most basic and milestone models of population growth was the logistic model of population growth formulated by Pierre François Verhulst in 1838. The logistic model takes the shape of a sigmoid curve and describes the growth of a population as exponential, followed by a decrease in growth, and bound by a carrying capacity due to environmental pressures.
Population modeling became of particular interest to biologists in the 20th century as pressure on limited means of sustenance due to increasing human populations in parts of Europe were noticed by biologist like Raymond Pearl. In 1921 Pearl invited physicist Alfred J. Lotka to assist him in his lab. Lotka developed paired differential equations that showed the effect of a parasite on its prey. Mathematician Vito Volterra equated the relationship between two species independent from Lotka. Together, Lotka and Volterra formed the Lotka–Volterra model for competition that applies the logistic equation to two species illustrating competition, predation, and parasitism interactions between species. In 1939 contributions to population modeling were given by Patrick Leslie as he began work in biomathematics. Leslie emphasized the importance of constructing a life table in order to understand the effect that key life history strategies played in the dynamics of whole populations. Matrix algebra was used by Leslie in conjunction with life tables to extend the work of Lotka. Matrix models of populations calculate the growth of a population with life history variables. Later, Robert MacArthur and E. O. Wilson characterized island biogeography. The equilibrium model of island biogeography describes the number of species on an island as an equilibrium of immigration and extinction. The logistic population model, the Lotka–Volterra model of community ecology, life table matrix modeling, the equilibrium model of island biogeography and variations thereof are the basis for ecological population modeling today.

Equations

Logistic growth equation:

Lotka-Volterra equation:

Island biogeography:

Species area:

Examples of individual-based models

Logical deterministic individual-based cellular automata model of an ecosystem with one species. The model demonstrates a mechanism of S-shaped population growth.

Logical deterministic individual-based cellular automata model of interspecific competition for a single limited resource. A mechanism of competitive exclusion of one species by another.

References

1. ^ ^a b Uyenoyama, Marcy; Rama Singh, Ed. (2004). The Evolution of Population Biology. Cambridge University Press. pp. 1–19. Cite uses deprecated parameter |coauthors= (help).
2. ^ Worster, Donald (1994). Nature's Economy. Cambridge University Press. pp. 398–401.
3. ^ ^a b McIntosh, Robert (1985). The Background of Ecology. Cambridge University Press. pp. 171–198.
4. ^ Renshaw, Eric (1991). Modeling Biological Populations in Space and Time. Cambridge University Press. pp. 6–9.
5. ^ Kingsland, Sharon (1995). Modeling Nature: Episodes in the History of Population Ecology. University of Chicago Press. pp. 127–146.
6. ^ Gotelli, Nicholas (2001). A Primer of Ecology. Sinauer.

External Links

• GreenBoxes code sharing network. Greenboxes (Beta) is a repository for open-source population modeling code. Greenboxes allows users an easy way to share their code and to search for others shared code.

- Wikipedia