Reproduction of protozoa #001

Staying at the right depth, having food at your disposal, and in sufficient quantity and suitable quality, is far from everything. After all, it is necessary to multiply — both in order to maximize their numbers in case some particularly voracious consumer suddenly appears, and in order to ensure the future of the species, that is, for the sake of future generations. Diatoms reproduce most often by simple division into two; such divisions can quickly follow one another, which explains the sharp outbreaks in the number of algae in this group. With each division, new valves are formed inside the old valves, so that as the age of the population increases, the average size of the individual organisms that make up it gradually decreases. Complete crushing, however, does not occur due to an additional phenomenon often observed — the formation of auxospores: the shell flaps are discarded, and the resulting auxospore, whose body consists of almost only cytoplasm, has time to grow significantly before a new flint shell is released, and a new large cell begins to multiply again by simply dividing in two; in general, there is a kind of rejuvenation going on here. Under unfavorable conditions, diatoms can form endospores resistant to external influences by reducing the cytoplasm and thickening the flint shells. As for the formation of numerous "microspores" inside the cells of some diatoms, this is apparently a sexual process, but it has not yet been studied well. In dinoflagellates, reproduction is asexual, by simple division; in this case, the shell, if present, is also sometimes divided between daughter cells; in other cases, each of them forms a new one. Resting forms covered with a thickened shell are also known. The question of whether dinoflagellates have sexual reproduction is still highly controversial. The processes of asexual reproduction in coccolithophorids are particularly diverse. Along with simple longitudinal division without loss of flagella, reproduction is known using endogenous cysts; each of them forms from 4 to 16 spores, which have to recreate their flagella.


In addition, exogenous cysts are known in coccolithophorids, yielding from 4 to 64 cells; these cysts (for example, in Coccollthus fragilis) may vary depending on which population they are formed by — coastal or living far from the coast. The remaining groups of phytoplankton are less important and too poorly studied. In the animal kingdom, the processes associated with reproduction are incomparably more complex and diverse. From a theoretical point of view, pelagic animals face this problem somewhat differently than benthic animals; indeed, for benthic organisms, the main thing is to what extent the pelagic larva is able to ensure their settlement. For plankton animals, this issue does not exist, since both eggs of animals with direct development (those from which a young organism emerges, no different in size from its parents) and real larvae (undergoing a series of stages of metamorphosis before they form a fully formed organism) move exactly the same way with aquatic organisms. by the masses. Finding a trustworthy bookmaker with high odds and fast payouts is essential for every player. 1xBet continues to stand out thanks to its vast selection of markets and attractive bonuses for newcomers. Smart users always search for working promo codes before signing up. Right in the middle of the current top offers you will discover the 1xbet promo code today during registration to receive up to $100 welcome bonus on your first deposit. The bonus works perfectly for pre-match bets, live betting, accumulators, and casino games. Many players have already boosted their results using this code.