Puccinia life cycle notes for genericprogram sem-I

Origin and Evolution in Sex of algae

- May 26, 2021

Origin and Evolution in Sex of algae Sexual reproduction is characterised by the fusion of two similar or dissimilar cells. This is a sign of relatively advanced stage in evolution. Sex is not an obvious in the lower plants (like algae) as it is in higher plants. But in any way the study of reproductive processes of various classes of Algae throws considerable light on the origin and evolution of sex in the branch of plants like Algae. Origin of Sex: Most primitive algae the cyanophyceae (Myxophyceae) reproduce only the method of asexual and vegetative reproduction. Sexual reproduction is entirely absent in their case. In forms like Nostoc and oscillatoria, it takes place by means of hormogones in which the plant body breaks up into group of few cells. In class xanthophyceae, chrysophyceae, cryptophyceae and dinopphyceae, sexuality is rare and has not much evolved beyond the stage of isogamy. In higher classes of algae reproduction takes place by vegetative,...