This interactive model illustrates the life cycle of various kinds of algae. Press "Run" button to run the model, press "Stop" to bring it to a halt, and press "Reset" to return the model to its initial state. Choose between different groups of algae by using switch buttons.
Brown algae reproduce sexually. This animation illustrates one of the methods of procreation of these organisms. The organs of reproduction of the brown algae, the gametangia, are commonly referred to as conceptacles. The gametangia grow on the talloms, known also as the fronds, of the algae. Male gametangia produce antheridia, or sperm cells, while the female conceptacles grow oogonia, or egg cells. The sperm cells leave the antheridia and fertilize the egg cells that mature inside the oogonia. Thus, a zygote is formed. A zygote undergoes intensive cell growth and division and, under favorable conditions, it eventually becomes a young alga.
Green algae, too, can reproduce sexually. The gametes that mature in the algae are emitted into water and fertilize each other, forming a zygote. The zygote divides by meiosis and grows intensively, producing spores. After a while, the spores enter the surroundings and give growth to new plants.
Sexual reproduction in green algae is often complimented by asexual reproduction, when one plant is enough to give growth to new algae. The spores that mature inside do not participate in the fertilization process but, rather, they sprout immediately, forming new plants.