Survival of the fittest was first used by British philosopher Herbert Spencer. Then it was used by Charles Darwin. Herbert Spencer first used the phrase after reading Charles Darwin’s On the Origin of Species. He used this term in his Principles of Biology (1864). He drew parallels between his own economic theories and Darwin’s biological ones. He writes that this ...

The evolution of ecological and phenotypic diversity within a rapidly multiplying lineage is called or known as adaptive radiation. It starts with a recent single ancestor. This process results in the speciation and phenotypic adaptation of species. These species exhibiting different morphological and physiological traits. Thus, they can exploit a range of divergent environments. Adaptive radiation can be graphically illustrated ...

In in vitro methods of germplasm conservation, the first germplasm conservation method is the Cryopreservation. Rest of the methods are as follow: In Vitro Methods of Germplasm Conservation (a) Cryopreservation in Cryopreservation (Greek- krayos-frost) In this case the cells are preserved in the frozen state. The germplasm is stored at a very low temperature using Solid carbon dioxide (at -790C) Using low temperature deep ...

Germplasm Conservation is sum total of all the genes present in a crop and its related species constitutes its germplasm. It is ordinarily represented by a collection of various strains and species. Germplasm provides the raw materials (= genes). The breeder uses these to develop commercial crop varieties. Therefore, germplasm is the basic indispensable ingredient of all breeding programmes. Thus, ...

Evolution is not a creative work force. It is not working for the progress. Evolution helps some individuals in a population to survive. They reproduce more effectively than others in the population. It causes changes in gene frequencies. Some factors do follow Hardy Weinberg assumptions. Therefore, gene are changed from one generation to the next. It causes evolution. Mechanisms of ...

Hardy Weinberg Equilibrium was the combined idea of English mathematician Godfrey H. Hardy and German physician Wilhelm Weinberg. They independently derived a mathematical model in 1908. This model explains what happens to the frequency of alleles in a population over time. Different Names The Hardy-Weinberg Equilibrium was given different names at that time. The names of that list is as follow: ...

The combination of the principles of population genetics and Darwinian evolutionary theory is called as modern synthesis. Modern synthesis comes from the study of genetics. It explains why variations exist among individuals. It also explains how they pass to the future generations. Modern Synthesis Theory of Evolution Some variations give an advantage to individuals. Therefore, nature selects them through natural ...

Gymnosperms term was given by “Theophrastus” in his book “Enquiry into plants”. Gymnosperm has been derived from Greek words. (Gymno = Bare/Naked) (Spermas = seeded). Characteristics of Gymnosperms The characteristics of gymnosperms are as follow. Sub Groups of Spermatophytes  According to “Geobel” known as “phanerogams”. (Hidden sex organs i.e. archegonium and Antheridium).   They can survive for several years. They ...

Evidences of Evolution shows the different species living on earth have evolved from simple to more advance and complex beings with the passage of time. And all the organisms have been evolved from a common ancestor known as Progenote Ancestor. Thus, these evidences support the evolution of organisms on earth. Evidences of Evolution from Biogeography The study at the geographic ...

On the basis of Photoperiodism responses the plants are divided in to different types by Garner & Allard. The short-day flowering plants, long-day flowering plants and day-neutral plants. Short-Day Flowering Plants The plants that flower when the day length is less than a certain critical length termed as short-day plants (SDPs). These plants require a specific short duration of light period for ...