Relacionar Columnas Origin and evolution of lifeVersión en línea Theories of evolution por Isabel Pérez Cotorruelo 1 Fixism 2 Lamarckism 3 Neo-darwinism 4 Puntuated equilibrium 5 Evolutionary development biology 6 Endosimbiosis theory 7 Darwinism 8 Neutralism Some genes act as switches for other gene groups during embrionic development. The necessity creates the organ. The acquired characteristics are transmitted to offsrping. The evolutionary process does not always take place in a slow gradual way. Instead in many cases new species are form rapidly. Eukariotic cells originated as a result of two different types of bacteria joining together. The reasons behind the variation within a species are mutations, genetic recombination and sexual reproduction. Individuals of a species that have more favourable characteristics survive more. Most mutations are neither benefitial nor harmful for the individuals that have them, so natural selection does not affect them. Living things do not change, species always stay the same
