Reproduction

Reproduction in algae is either sexual or asexual. Cyanobacteria only reproduce asexually, with genetic recombination accomplished through transformation or conjugation. During transformation DNA, released from donor cells, is incorporated into recipient cells. Conjugation is the process by which two cells become connected by a narrow tube, through which DNA moves from one cell into the other. Other algal groups use various sexual or asexual methods which are fairly group specific, but some features are shared. When reproducing asexually most groups develop spores within a parent cell which are released into the environment. Each of these spores develops into a single algal cell or they divide mitotically into numerous cells. For example, reproduction in the cryptomonads is asexual and primarily via longitudinal cell division with the cell dividing in either a free-swimming or nonmotile condition. Sexual reproduction is not rare but occurs less often than asexual reproduction. Gametes are produced in different algal cells and released into the environment. Male gametes usually attach themselves to female gametes and their genetic material is absorbed through the cell coat of the female. In freshwater species, this is followed by the formation of a cyst in which meiosis takes place. More details on the specifics of reproduction are provided in the discussions on each algal group.