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Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae. The term 'angiosperm' is derived from the Greek words ἀγγεῖον / angeion and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit. The group was formerly called Magnoliophyta.
Pangenesis was Charles Darwin's hypothetical mechanism for heredity, in which he proposed that each part of the body continually emitted its own type of small organic particles called gemmules that aggregated in the gonads, contributing heritable information to the gametes. He presented this 'provisional hypothesis' in his 1868 work The Variation of Animals and Plants Under Domestication, intending it to fill what he perceived as a major gap in evolutionary theory at the time. The etymology of the word comes from the Greek words pan and genesis ("birth") or genos ("origin"). Pangenesis mirrored ideas originally formulated by Hippocrates and other pre-Darwinian scientists, but using new concepts such as cell theory, explaining cell development as beginning with gemmules which were specified to be necessary for the occurrence of new growths in an organism, both in initial development and regeneration. It also accounted for regeneration and the Lamarckian concept of the inheritance of acquired characteristics, as a body part altered by the environment would produce altered gemmules. This made Pangenesis popular among the neo-Lamarckian school of evolutionary thought. This hypothesis was made effectively obsolete after the 1900 rediscovery among biologists of Gregor Mendel's theory of the particulate nature of inheritance.
Fertilisation or fertilization, also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or offspring. While processes such as insemination or pollination, which happen before the fusion of gametes, are also sometimes informally referred to as fertilisation, these are technically separate processes. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms, the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation.
Selective breeding is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, cultivars, or breeds. Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids. Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals.
Quantitative genetics is the study of quantitative traits, which are phenotypes that vary continuously—such as height or mass—as opposed to phenotypes and gene-products that are discretely identifiable—such as eye-colour, or the presence of a particular biochemical.
Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. The heterotic offspring often has traits that are more than the simple addition of the parents' traits, and can be explained by Mendelian or non-Mendelian inheritance. Typical heterotic/hybrid traits of interest in agriculture are higher yield, quicker maturity, stability, drought tolerance etc.
Blending inheritance is an obsolete theory in biology from the 19th century. The theory is that the progeny inherits any characteristic as the average of the parents' values of that characteristic. As an example of this, a crossing of a red flower variety with a white variety of the same species would yield pink-flowered offspring.
The Power of Movement in Plants is a book by Charles Darwin on phototropism and other types of movement in plants. This book continues his work in producing evidence for his theory of natural selection. As it was one of his last books, followed only by the publication of The Formation of Vegetable Mould through the Action of Worms, he was assisted by his son Francis in conducting the necessary experiments and preparing the manuscript. The Power of Movement in Plants was published 6 November 1880, and 1500 copies were quickly sold by publisher John Murray.
The history of genetics dates from the classical era with contributions by Pythagoras, Hippocrates, Aristotle, Epicurus, and others. Modern genetics began with the work of the Augustinian friar Gregor Johann Mendel. His works on pea plants, published in 1866, provided the initial evidence that, on its rediscovery in 1900's, helped to establish the theory of Mendelian inheritance.
Between 1873 and 1882, the life and work of Charles Darwin from Insectivorous Plants to Worms continued with investigations into carnivorous and climbing plants that had begun with his previous work. Worries about family illnesses contributed to his interest in Galton's ideas of "hereditary improvement". He continued to help with the work of Downe parish church and associated village amenities, despite problems with control being seized by a new High Church vicar, and he remained on good terms with the Church's patron, the Revd. John Brodie Innes. There was continuing interest in Charles Darwin's views on religion, but he remained reticent.
Inbreeding depression is the reduced biological fitness that has the potential to result from inbreeding. The loss of genetic diversity that is seen due to inbreeding, results from small population size. Biological fitness refers to an organism's ability to survive and perpetuate its genetic material. Inbreeding depression is often the result of a population bottleneck. In general, the higher the genetic variation or gene pool within a breeding population, the less likely it is to suffer from inbreeding depression, though inbreeding and outbreeding depression can simultaneously occur.
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity.
Charles Robert Darwin was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey.
The history of model organisms began with the idea that certain organisms can be studied and used to gain knowledge of other organisms or as a control (ideal) for other organisms of the same species. Model organisms offer standards that serve as the authorized basis for comparison of other organisms. Model organisms are made standard by limiting genetic variance, creating, hopefully, this broad applicability to other organisms.
Plant evolution is the subset of evolutionary phenomena that concern plants. Evolutionary phenomena are characteristics of populations that are described by averages, medians, distributions, and other statistical methods. This distinguishes plant evolution from plant development, a branch of developmental biology which concerns the changes that individuals go through in their lives. The study of plant evolution attempts to explain how the present diversity of plants arose over geologic time. It includes the study of genetic change and the consequent variation that often results in speciation, one of the most important types of radiation into taxonomic groups called clades. A description of radiation is called a phylogeny and is often represented by type of diagram called a phylogenetic tree.
Edward Murray East was an American plant geneticist, botanist, agronomist and eugenicist. He is known for his experiments that led to the development of hybrid corn and his support of 'forced' elimination of the 'unfit' based on eugenic findings. He worked at the Bussey Institute of Harvard University where he performed a key experiment showing the outcome of crosses between lines that differ in a quantitative trait. He is also known as a critic of consumption and as a pioneer of thinking about environmental limits. While some scholars see his population thinking as nothing more than eugenics on a global scale, others see his population thinking as driven by environmental concerns, not eugenics.
Fertilisation of Orchids is a book by English naturalist Charles Darwin published on 15 May 1862 under the full explanatory title On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects, and On the Good Effects of Intercrossing. Darwin's previous book, On the Origin of Species, had briefly mentioned evolutionary interactions between insects and the plants they fertilised, and this new idea was explored in detail. Field studies and practical scientific investigations that were initially a recreation for Darwin—a relief from the drudgery of writing—developed into enjoyable and challenging experiments. Aided in his work by his family, friends, and a wide circle of correspondents across Britain and worldwide, Darwin tapped into the contemporary vogue for growing exotic orchids.
Das entdeckte Geheimnis der Natur im Bau und in der Befruchtung der Blumen by Christian Konrad Sprengel was published in 1793, but received little acclaim during the author's lifetime. Sprengel's ideas were rejected by other naturalists when it was published, but the importance of this work was duly appreciated by Charles Darwin some sixty years later. Darwin's use of Sprengel's ideas and reference to this book in the seminal work on the Fertilisation of Orchids established Sprengel's book as one of the most important works in the fields of floral biology and pollination ecology and its author as a founding father of these fields.
A mixed mating system, also known as “variable inbreeding” a characteristic of many hermaphroditic seed plants, where more than one means of mating is used. Mixed mating usually refers to the production of a mixture of self-fertilized (selfed) and outbred (outcrossed) seeds. Plant mating systems influence the distribution of genetic variation within and among populations, by affecting the propensity of individuals to self-fertilize or cross-fertilize . Mixed mating systems are generally characterized by the frequency of selfing vs. outcrossing, but may include the production of asexual seeds through agamospermy. The trade offs for each strategy depend on ecological conditions, pollinator abundance and herbivory and parasite load. Mating systems are not permanent within species; they can vary with environmental factors, and through domestication when plants are bred for commercial agriculture.
Ken Thompson is a botanist and writer of popular books on botany. He is a retired Senior Research Fellow of Sheffield University and has written for the newspaper Telegraph. He is also an editor for the journal Functional Ecology.