A body plan, or bauplan, is essentially the blueprint for the way the body of an organism is laid out. An organism's symmetry,[1] its number of body segments and number of limbs are all aspects of its body plan. "Bilateral symmetry" redirects here For bilateral symmetry in mathematics see Reflection symmetry. Segmentation in biology refers to the division of some Metazoan bodies and Plant body plans into a series of semi-repetitive segments and the question of A limb (from the Old English lim) is a jointed or Prehensile (as Octopus tentacles or new world Monkey tails Appendage of the One of the key issues of developmental biology is the evolution of body plans as different as those of a starfish, a fern, or a mammal, from a common biological heritage, and in particular how radical changes in body plans have occurred over geological time. Developmental Biology is the official journal of the Society for Developmental Biology. The body plan is a key feature of an organism's morphology, and since the discovery of DNA developmental biologists have been able to learn a lot about how genes control the development of structural features through a cascade of processes in which key genes produce morphogens, chemicals that diffuse through the body to produce a gradient that acts as a position indicator for cells, turning on other genes, some of which in turn produce other morphogens. The term morphology in Biology refers to the outward appearance ( Shape, Structure, Colour, Pattern) of an Organism Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known A morphogen is a substance governing the pattern of tissue development and in particular the positions of the various specialized cell types within a tissue A key discovery was the existence of groups of homeobox genes which are responsible for laying down the basic body plan in organisms. A homeobox is a DNA sequence found within Genes that are involved in the regulation of patterns of development ( Morphogenesis) in Animals The homeobox genes are remarkably conserved between species as diverse as the fruitfly and man, the basic segmented pattern of the worm or fruitfly being the origin of the segmented spine in man. The field of evolutionary developmental biology, which studies the genetics of morphology in detail is now a rapidly expanding one [1], with many of the developmental genetic cascades, particularly in the fruitfly drosophila, now catalogued in considerable detail . Drosophila is a Genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" [2] .
Body plan is the basis for phylum, and there are 35 different basic animal body plans, corresponding to different phyla. A phylum ( Plural: phyla) is a Taxonomic rank between Kingdom and above Class.
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Origin
The evolution of body plans became inevitable with the emergence of differentiated multicellular life in the Ediacaran Era, over 600 million years ago. Multicellular organisms are Organisms consisting of more than one cell, and having Differentiated cells that perform specialized functions The Ediacaran Period (ˌiːdiˈækərən named after the Ediacara Hills of South Australia) is the last geological period of the Neoproterozoic The most basic and successful structure, for free-moving organisms, is the "pipe" or alimentary canal. This is common even to organisms as diverse as humans and earthworms. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Earthworm is the usual name for the largest members of Oligochaeta (which is either a class or subclass depending on the author in the phylum Annelida In classical It is essentially a passage having a mouth at one end, and a cloaca or anus at the other. The simple process of nutrient capture, digestion, and waste disposal is fundamental to the body plan of advanced, free-moving animals. Vertebra, limbs, even brains are supplementary to the pipe. Natural selection has spun off an enormous range of variations on this basic theme, but the pipe model itself remains. The basic symmetry and organization of this body plan apparently gave an ancient organism an enormous advantage at survival and reproduction, and it has been preserved in most animals ever since.
The Cambrian explosion refers to the massive increase in different body plans that took place around 530 million years ago. The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex Animals around, as evidenced by the Fossils from this era show all sorts of weird and wonderful shapes, many quite unlike anything found today. At that time it was possible for organisms to survive and make a living even though they were unrefined and unlikely, because predation had yet to evolve, along with arms races that would optimise and streamline them to occupy a particular ecological niche. The Red Queen's Hypothesis, Red Queen, " Red Queen's race " or " Red Queen Effect " is an Evolutionary Hypothesis In Ecology, a niche (pronounced nich nēsh or nish A shorthand definition of niche is how an organism makes a living
Bauplan
Bauplan (German for building plan, blueprint; plural: baupläne or bauplaene) is a closely related term in biology referring to the common new and original (homologous) properties of the members of a systematic group (taxon). A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to It is not necessary that a bauplan precisely describes any one particular species of that group.
The concept of bauplan is employed in the studies of morphology, taxonomy, comparative physiology and, most notably, phylogenetics and evolution. Before the advent of genetic sequencing, the analysis of the bauplan of fossils was an important method to devise hypothetical relationships and lineages of species, both living and extinct. The idea is, that species that are closely related share more common properties, hence a more detailed bauplan. Small differences of bauplan are indicative of species belonging to a parent, child or sibling taxon.
Examples
The current range of body plans is far from exhausting the possible patterns for terrestrial life: the Ediacaran biota appears to contain numerous species and taxa with body plans quite different from any found in currently living organisms. Ichthyostega (Greek "fish roof" is an early Tetrapod Genus that lived in the Upper Devonian ( Famennian) period 367-362 The Ediacara (ˌiːdɪˈækərə formerly Vendian) biota are ancient lifeforms of the Ediacaran Period which represent the earliest known complex A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to
The most commonly seen body plan amongst vertebrates is that of the tetrapod, which include all mammals, birds, amphibians and reptiles. Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers Some animal groups, such as the cetaceans, bats and most birds have been modified (e. The Order Cetacea (sɪˈteɪʃiə L cetus, whale includes Whales Dolphins and Porpoises Cetus is g. front limbs become wings or flippers) but nevertheless, they are still tetrapods.
The invertebrates employ a much more diverse array of body plans, such as seen in insects (six legs, three body parts and an exoskeleton), cephalopods (no skeleton, hydrostatically stiffened tentacles, primary propulsion by squeezing water out of a mantle cavity), echinoderms (five-fold radial symmetry, external skeleton, movement by hydrostatically operated tube feet) and various phyla of "worms" (tube-shaped, movement by expanding and contracting parts of the body). An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described The cephalopods ( Greek plural (kephalópoda "head-feet" are the Mollusc class Cephalopoda characterized by Echinoderms (Phylum Echinodermata) are a phylum of marine Animals (including Sea stars)
The most varied collection of body forms known is found in the Burgess Shale, where fossils from a Cambrian sea show a tremendous variety of body forms that came to rise (only to later fall extinct) during the Cambrian explosion. See also Burgess shale type fauna The Burgess Shale is famous for the exceptional preservation of the fossils found within it in which the soft parts are preserved The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex Animals around, as evidenced by the
Fictional
One common theme in science fiction is the appearance of extraterrestrial beings, descriptions of which have ranged from being simple variants on human anatomy to beings with body plans wildly different from any found on Earth. The field of exobiology attempts to bring these and similar speculations into the realm of serious scientific investigation. Astrobiology (from Greek grc ἄστρον astron, "constellation star" grc βίος bios, "life" and grc -λογία
See also
- Anatomical terms of location
- Deep homology
- Evolutionary developmental biology
- Ediacaran biota
- Homeobox
- Macroevolution
- Sean B. Carroll
- Supernumerary body part
- Symmetry (biology)
- Wallace Arthur
Video
References
- ^ Up and down...or around and around? Body Symmetry in Animals (Web). In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species In Evolutionary developmental biology, the concept of deep homology is used to describe cases where growth and differentiation processes are governed by Evolutionary developmental biology ( evolution of development or informally evo-devo) is a field of Biology that compares the developmental processes The Ediacara (ˌiːdɪˈækərə formerly Vendian) biota are ancient lifeforms of the Ediacaran Period which represent the earliest known complex A homeobox is a DNA sequence found within Genes that are involved in the regulation of patterns of development ( Morphogenesis) in Animals Macroevolution is a scale of analysis of Evolution in separated Gene pools Macroevolutionary studies focus on change that occurs at or above the level of Species Sean B Carroll (born September 17th 1960 is a Howard Hughes Medical Institute investigator at the University of Wisconsin-Madison. Supernumerary body parts are most commonly a Congenital disorder involving the growth of an additional part of the Body and a deviation from the Body plan "Bilateral symmetry" redirects here For bilateral symmetry in mathematics see Reflection symmetry. Wallace Arthur is a zoologist specialising in Evolutionary developmental biology. The Diversity of Living Organisms: Themes of Adaptation and Evolution. Kennesaw State University. Retrieved on 2007-12-01. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 800 - Charlemagne judges the accusations against Pope Leo III in the Vatican
- ^ Arthur, Wallace. (1997). Wallace Arthur is a zoologist specialising in Evolutionary developmental biology. Animal Body Plans. Cambridge England: Cambridge University Press. ISBN 0-521-77928-6.
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