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Evolutionary Mismatch
Evolutionary mismatch, also known as mismatch theory or evolutionary trap, is a concept in evolutionary biology that refers to evolved traits that were once advantageous but became maladaptive due to changes in the environment. This can take place in humans and animals and is often attributed to rapid environmental change. Mismatch theory represents the idea that traits that evolved in an organism in one environment can be disadvantageous in a different environment. This environmental change leading to evolutionary mismatch can be broken down into two major categories: temporal (change of the existing environment over time, e.g. a climate change) or spatial (placing organisms into a new environment, e.g. a population migrating). Since environmental change occurs naturally and constantly, there will certainly be examples of evolutionary mismatch over time. However, because large-scale natural environmental change – like a natural disaster – is often rare, it is less often ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Trap
The term evolutionary trap has retained several definitions associated with different biological disciplines. Within evolutionary biology, this term has been used sporadically to refer to cases in which an evolved, and presumably adaptive, trait has suddenly become maladaptive, leading to the extinction of the species. Within behavioral and ecological sciences, evolutionary traps occur when rapid environmental change triggers organisms to make maladaptive behavioral decisions. While these traps may take place within any type of behavioral context (e.g. mate selection, navigation, nest-site selection), the most empirically and theoretically well-understood type of evolutionary trap is the ecological trap which represents maladaptive habitat selection behavior. Witherington demonstrates an interesting case of a "navigational trap". Over evolutionary time, hatchling sea turtles have evolved the tendency to migrate toward the light of the moon upon emerging from their sand nests. Ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolithic Revolution
The Neolithic Revolution, or the (First) Agricultural Revolution, was the wide-scale transition of many human cultures during the Neolithic period from a lifestyle of hunting and gathering to one of agriculture and settlement, making an increasingly large population possible. These settled communities permitted humans to observe and experiment with plants, learning how they grew and developed. This new knowledge led to the domestication of plants into crops. Archaeological data indicates that the domestication of various types of plants and animals happened in separate locations worldwide, starting in the geological epoch of the Holocene 11,700 years ago. It was the world's first historically verifiable revolution in agriculture. The Neolithic Revolution greatly narrowed the diversity of foods available, resulting in a downturn in the quality of human nutrition compared with that obtained previously from foraging. The Neolithic Revolution involved far more than the adopt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphine
Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. There are numerous methods used to administer morphine: oral; sublingual; via inhalation; injection into a muscle; by injection under the skin; intravenously; injection into the space around the spinal cord; transdermal; or via rectal suppository. It acts directly on the central nervous system (CNS) to induce analgesia and alter perception and emotional response to pain. Physical and psychological dependence and tolerance may develop with repeated administration. It can be taken for both acute pain and chronic pain and is frequently used for pain from myocardial infarction, kidney stones, and during labor. Its maximum effect is reached after about 20 minutes when administered intravenously and 60 minutes when administered by mout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotine
Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As a pharmaceutical drug, it is used for smoking cessation to relieve drug withdrawal, withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors (nAChRs), except at two nicotinic receptor subunits (nAChRα9 and nAChRα10) where it acts as a receptor antagonist. Nicotine constitutes approximately 0.6–3.0% of the dry weight of tobacco. Nicotine is also present at Parts-per notation, ppb-concentrations in edible plants in the family Solanaceae, including potatoes, tomatoes, and eggplants, though sources disagree on whether this has any biological significance to human consumers. It functions as an plant defense against herbivory, antiherbivore toxin; consequently, nicotine was widely used as an insectic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Behavioral Addiction
Behavioral addiction is a form of addiction that involves a compulsion to engage in a rewarding non- substance-related behavior – sometimes called a natural reward – despite any negative consequences to the person's physical, mental, social or financial well-being. Addiction canonically refers to substance abuse; however, the term's connotation has been expanded to include behaviors that may lead to a reward (such as gambling, eating, or shopping) since the 1990s. A gene transcription factor known as ΔFosB has been identified as a necessary common factor involved in both behavioral and drug addictions, which are associated with the same set of neural adaptations in the reward system. Psychiatric and medical classifications Diagnostic models do not currently include the criteria necessary to identify behaviors as addictions in a clinical setting. Behavioral addictions have been proposed as a new class in ''DSM-5'', but the only category included is gambling addiction. Interne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dopamine
Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% of the catecholamine content in the brain. It is an amine synthesized by removing a carboxyl group from a molecule of its precursor chemical, L-DOPA, which is synthesized in the brain and kidneys. Dopamine is also synthesized in plants and most animals. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons (nerve cells) to send signals to other nerve cells. Neurotransmitters are synthesized in specific regions of the brain, but affect many regions systemically. The brain includes several distinct dopamine pathways, one of which plays a major role in the motivational component of reward-motivated behavior. The anticipation of most types of rewards increases the level of dopamine in the brain, and many ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reward System
The reward system (the mesocorticolimbic circuit) is a group of neural structures responsible for incentive salience (i.e., "wanting"; desire or craving for a reward and motivation), associative learning (primarily positive reinforcement and classical conditioning), and positively-valenced emotions, particularly ones involving pleasure as a core component (e.g., joy, euphoria and ecstasy). Reward is the attractive and motivational property of a stimulus that induces appetitive behavior, also known as approach behavior, and consummatory behavior. A rewarding stimulus has been described as "any stimulus, object, event, activity, or situation that has the potential to make us approach and consume it is by definition a reward". In operant conditioning, rewarding stimuli function as positive reinforcers; however, the converse statement also holds true: positive reinforcers are rewarding. The reward system motivates animals to approach stimuli or engage in behaviour that incr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dopaminergic Pathways
Dopaminergic pathways (dopamine pathways, dopaminergic projections) in the human brain are involved in both physiological and behavioral processes including movement, cognition, executive functions, reward, motivation, and neuroendocrine control. Each pathway is a set of projection neurons, consisting of individual dopaminergic neurons. The four major dopaminergic pathways are the mesolimbic pathway, the mesocortical pathway, the nigrostriatal pathway, and the tuberoinfundibular pathway.The mesolimbic pathway and the mesocortical pathway form the mesocorticolimbic system. Two other dopaminergic pathways to be considered are the hypothalamospinal tract and the incertohypothalamic pathway. Parkinson's disease, attention deficit hyperactivity disorder (ADHD), substance use disorders (addiction), and restless legs syndrome (RLS) can be attributed to dysfunction in specific dopaminergic pathways. The dopamine neurons of the dopaminergic pathways synthesize and release the neur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hygiene Hypothesis
In medicine, the hygiene hypothesis states that early childhood exposure to particular microorganisms (such as the gut flora and helminth parasites) protects against allergic diseases by contributing to the development of the immune system. In particular, a lack of exposure is thought to lead to defects in the establishment of immune tolerance. The time period for exposure begins ''in utero'' and ends at school age. While early versions of the hypothesis referred to exposure to microbes in general, updated versions apply to a specific set of microbial species that have co-evolved with humans. The updates have been given various names, including the microbiome depletion hypothesis, the microflora hypothesis, and the "old friends" hypothesis. There is a significant amount of evidence supporting the idea that lack of exposure to these microbes is linked to allergies or other conditions, although scientific disagreement still exists. The term "hygiene hypothesis" has been described ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone among the elderly. Bones that commonly break include the vertebrae in the spine, the bones of the forearm, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. After the broken bone heals, the person may have chronic pain and a decreased ability to carry out normal activities. Osteoporosis may be due to lower-than-normal maximum bone mass and greater-than-normal bone loss. Bone loss increases after the menopause due to lower levels of estrogen, and after ' andropause' due to lower levels of testosterone. Osteoporosis may also occur due to a number of diseases or treatments, including alcoholism, anorexia, hyperthyroidism, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diabetes Mellitus Type 2
Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, and unexplained weight loss. Symptoms may also include increased hunger, feeling tired, and sores that do not heal. Often symptoms come on slowly. Long-term complications from high blood sugar include heart disease, strokes, diabetic retinopathy which can result in blindness, kidney failure, and poor blood flow in the limbs which may lead to amputations. The sudden onset of hyperosmolar hyperglycemic state may occur; however, ketoacidosis is uncommon. Type 2 diabetes primarily occurs as a result of obesity and lack of exercise. Some people are genetically more at risk than others. Type 2 diabetes makes up about 90% of cases of diabetes, with the other 10% due primarily to type 1 diabetes and gestational diabetes. In type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolic Syndrome
Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndrome is associated with the risk of developing cardiovascular disease and type 2 diabetes. In the U.S., about 25% of the adult population has metabolic syndrome, a proportion increasing with age, particularly among racial and ethnic minorities. Insulin resistance, metabolic syndrome, and prediabetes are closely related to one another and have overlapping aspects. The syndrome is thought to be caused by an underlying disorder of energy utilization and storage. The cause of the syndrome is an area of ongoing medical research. Signs and symptoms The key sign of metabolic syndrome is central obesity, also known as visceral, male-pattern or apple-shaped adiposity. It is characterized by adipose tissue accumulation predominantly around ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
