History of evolutionary thoughtEvolutionary thought, the recognition that species change over time and the perceived understanding of how such processes work, has roots in antiquity—in the ideas of the ancient Greeks, Romans, Chinese, Church Fathers as well as in medieval Islamic science.
FractionA fraction (from fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, three-quarters. A common, vulgar, or simple fraction (examples: and ) consists of an integer numerator, displayed above a line (or before a slash like ), and a non-zero integer denominator, displayed below (or after) that line.
Placental abruptionPlacental abruption is when the placenta separates early from the uterus, in other words separates before childbirth. It occurs most commonly around 25 weeks of pregnancy. Symptoms may include vaginal bleeding, lower abdominal pain, and dangerously low blood pressure. Complications for the mother can include disseminated intravascular coagulopathy and kidney failure. Complications for the baby can include fetal distress, low birthweight, preterm delivery, and stillbirth. The cause of placental abruption is not entirely clear.
Plant evolutionary developmental biologyEvolutionary developmental biology (evo-devo) is the study of developmental programs and patterns from an evolutionary perspective. It seeks to understand the various influences shaping the form and nature of life on the planet. Evo-devo arose as a separate branch of science rather recently. An early sign of this occurred in 1999. Most of the synthesis in evo-devo has been in the field of animal evolution, one reason being the presence of model systems like Drosophila melanogaster, C. elegans, zebrafish and Xenopus laevis.
Conserved quantityA conserved quantity is a property or value that remains constant over time in a system even while changes occur in the system. In mathematics, a conserved quantity of a dynamical system is formally defined as a function of the dependent variables, the value of which remains constant along each trajectory of the system. Not all systems have conserved quantities, and conserved quantities are not unique, since one can always produce another such quantity by applying a suitable function, such as adding a constant, to a conserved quantity.
Lower PaleolithicThe Lower Paleolithic (or Lower Palaeolithic) is the earliest subdivision of the Paleolithic or Old Stone Age. It spans the time from around 3.3 million years ago when the first evidence for stone tool production and use by hominins appears in the current archaeological record, until around 300,000 years ago, spanning the Oldowan ("mode 1") and Acheulean ("mode 2") lithics industries. In African archaeology, the time period roughly corresponds to the Early Stone Age, the earliest finds dating back to 3.
HomoHomo () is the genus that emerged from the genus Australopithecus and encompasses the extant species Homo sapiens (modern humans) and several extinct species classified as either ancestral to or closely related to modern humans, including Homo erectus and Homo neanderthalensis. The oldest member of the genus is Homo habilis, with records of just over 2 million years ago. Homo, together with the genus Paranthropus, is probably sister to Australopithecus africanus, which itself had split from the lineage of Pan, the chimpanzees.
