acquired characteristic acquired characteristic an acquired characteristic is a non-heritable change in a function or structure of a living organism caused after birth by disease, injury, accident, deliberate modification, variation, repeated use, disuse, misuse, or other environmental influence. acquired traits are synonymous with acquired characteristics. they are not passed on to offspring through reproduction. the changes that constitute acquired characteristics can have many manifestations and degrees of visibility, but they all have one thing in common. they change a facet of a living organism's function or structure after birth. for example: the muscles acquired by a bodybuilder through physical training and diet. the loss of a limb due to an injury. the miniaturization of bonsai plants through careful cultivation techniques. acquired characteristics can be minor and temporary like bruises, blisters, or shaving body hair. permanent but inconspicuous or invisible ones are corrective eye surgery and organ transplant or removal. semi-permanent but inconspicuous or invisible traits are vaccination and laser hair removal. perms, tattoos, scars, and amputations are semi-permanent and highly visible. applying makeup, nail polish, dying one's hair, applying henna to the skin, and tooth whitening are not examples of acquired traits. they change the appearance of a facet of an organism, but do not change the structure or functionality. inheritance of acquired characteristics was historically proposed by renowned theorists such as hippocrates, aristotle, and french naturalist jean-baptiste lamarck. conversely, this hypothesis was denounced by other renowned theorists such as charles darwin. today, although lamarckism is generally discredited, there is still debate on whether some acquired characteristics in organisms are actually inheritable. disputes acquired characteristics, by definition, are characteristics that are gained by an organism after birth as a result of external influences or the organism's own activities which change its structure or function and cannot be inherited. inherited characteristics, by definition, are characteristics that are gained or to which an organism is predisposed as a result of genetic transmission from its parents and can be passed to the organism's offspring. therefore, every condition an organism does not gain or develop because of inheritance of its parents' genetic information must be considered an acquired characteristic. eye color it is fairly common for mammalian eyes to change color in the first years of life. this happens, with human infants and kittens being some well-known examples, because the eyes of the baby, just like the rest of its body, are still developing. this change can be as simple as blue to brown, or can involve multiple color changes in which neither the child's parents nor his/her doctors know when the changes will stop and what the final eye color will be. changes in eye color signal changes in the arrangement and concentration of pigment in the iris, which is an example of structural color. even though this change happens after birth, it is strictly as result of genes. while changes in eye appearance (and function, and structure) that occur because of acquired characteristics like injury, illness, old age, or malnutrition are definitely acquired characteristics, the infantile color change as described above is usually considered inherited. certain genetic conditions further information on the correlation between health, genetics, and environment: gene–environment correlation, gene-environment interaction, risk factor, genetic predisposition, environment and intelligence, physical health § determinants of health, and behavioural genetics when diseases are caused by environmental influences, such as iodine deficiency or lead poisoning, their resultant symptoms are unequivocally agreed to be acquired characteristics. however, it is debatable whether changes in bodily functions due to disorders that are partly or wholly genetic in origin are actually "acquired". wholly genetic disorders, such as huntingtons, are inherited from parents' genes and are present before birth but the symptoms that develop after birth are delayed manifestations of the inherited trait. disorders that are partially genetic, such as als and allergies, mean the organism has inherited a predisposition to develop a certain condition but that inherited increased likelihood can be reduced or further increased depending on acquired characteristics of the organism. de novo mutations new mutations, (often somatic, spontaneous and sporadic), not inherited from either parent are called de novo mutations. the consensus on whether certain prenatal spontaneous mutations and genetic disorders that occur as a result of meiotic and chromosome errors or during cell division after conception, like cystic fibrosis and down syndrome, are considered to be acquired or inherited is unclear. mutations and meiotic errors can be considered inherited since the organism is born with them in its genes, but they can also be seen as prenatal acquired characteristics since they are not actually inherited from its parents. with de novo mutations and division errors, the relationship between the offspring's altered genes and gene inheritance from the parents is technically spurious. these genetic errors can affect the mind as well as the body and can result in schizophrenia, autism, bi-polar disorder, and cognitive disabilities. further information on mutations and cell division errors: cystic fibrosis § cause, genetic origins of down syndrome, causes of autism, chromosome abnormality, and mutation prenatal conditions the definitions of inherited and acquired characteristics leave a gray area for trauma, pre-existing and gestational maternal conditions that affect the fetus, as well as chemical and pathogen exposures and trauma that happen before and while an organism is born, such as aids, syphilis, hepatitis b, chickenpox, rubella, unregulated gestational diabetes, and fetal alcohol syndrome. most infections won't affect a fetus if the pregnant mother contracts it, but some can be transmitted to babies via the placenta or during birth, and others cause more severe symptoms in pregnant women or can cause complications to the pregnancy. types the world health organization defines health as "a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity." acquired characteristics do not necessarily affect the health of an organism, (a scar, suntan, or perm) but examples that do are often the first that come to mind when thinking of acquired characteristics since they are the easiest to observe and the ones that we, ourselves, are most familiar with. physical physical acquired characteristics can stem from various environmental influences such as disease, modification, injury, and regular or infrequent use of body parts. mental mental traits are acquired by learning and adapting native traits to the environment of the individual. sentiments are the result of the compounding of primary emotions, being "bound up with knowledge and ideas." only through vast experience in the natural world can humans learn to recognize objects in all of the various orientations in which we encounter them on a day-to-day basis. the ability to do something well is an acquired characteristic, since a skill comes from one's knowledge, practice, aptitude, etc. period of origin there are mainly four types of disease: pathogenic disease deficiency disease hereditary disease physiological disease prenatal congenital disorders, or birth defects, are conditions present at birth. they may be structural or functional, and can result from genetic or chromosomal disorders or from environmental factors during pregnancy. environmental factors may include exposure to chemicals, infections, or physical trauma. chemical exposure main article: prenatal exposure § exposure to toxins hormones are chemicals released by a cell or a gland in one part of the body that affect cells in other parts of the organism. chemicals are substances with distinct molecular compositions that are produced by or used in a chemical process. while all types of asbestos fibers are known to cause serious health hazards in humans, maternal conditions during gestation worth noting is the importance of prenatal nutrition to proper mental and physical development. a correlation between fraternal birth order and male sexual orientation has been suggested to be responsible for up to 15 percent of homosexuality. it is hypothesized to have something to do with changes induced in the mother's body when gestating a boy that affects subsequent sons, possibly an in-utero maternal immune response. there is also reason to believe that the immune system of a baby will be healthier if, during pregnancy, the mother's immune system was regularly stimulated by exposure to pathogens. "...a mother's farm exposure affects her baby's t regulatory cells. these cells, it is now believed, act to suppress immune responses and thereby maintain immune system homeostasis to contribute to healthy immune development. ... the babies of mothers exposed to farms have more and better functioning regulatory t cells."— childhood main article: helminthic therapy