Sexually reproducing animals, plants, fungi and protists are thought to have evolved from a common ancestor that was a single-celled eukaryotic species. Sexual reproduction is widespread in eukaryotes
Ladybirds mating
Pollen production is an essential step in sexual reproduction of seed plants.
Schematic illustration of the advantage of the first sexual individual resulting from the seesaw effect. Possible combinations of the sex allele (S) and non-sex allele (N) entering the clean genome (C) or dirty genome (D) are shown. S (dominant over N) controls meiosis and fusion. α is the deviation from equal division of dms (deleterious genes) over two genomes. The first automictic selfing event is successful with a 50% probability.
Darwin's finches by Gould
Bdelloidea
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Bdelloidea is a class of rotifers found in freshwater habitats all over the world. There are over 450 described species of bdelloid rotifers, distinguished from each other mainly on the basis of morph
Evolution of sexual reproduction
…Sexual reproduction is widespread in eukaryotes, though a few eukaryotic species have secondarily lost the ability to reproduce sexually, such as Bdelloidea, and some plants and animals routinely reproduce asexually (by apomixis and parthenogenesis) without entirely having lost sex. The evolution of sexual…
Bdelloid
Lateral view of a bdelloid.
Frontal view of a bdelloid's corona.
Lateral view of a bdelloid.