Question

What are zoospores? Give two suitable examples.

Answer 1

Hint: The term ‘Zoo’ means animals and ‘spores’ means a moment. It has motile spores and uses flagella for locomotion. The reproductive unit is able to give rise to an individual without sexual fusion.

Complete answer:
A zoospore is a spore that is motile in nature. They are asexual animals, as they give rise to new individuals without sexual fusion. They are naked and wall-less cells. They use flagella for locomotion. The flagella also help to swim in aquatic habitats for correct dispersal. They swim for several hours, using endogenous food reserves, then encyst by retracting or shedding their flagella and secreting a wall. Under conditions like water scarcity and unfavorable conditions of growth, they will behave as gametes and undergo fusion to make the resting structure called a zygote.
Examples include spores of some algae, fungi, and protozoans i.e. Phytophthora, Saprolegnia, Albugo, Achlya, etc.

Additional Information: In eukaryotes, there are four main types of zoospore are-
-Posterior whiplash flagella, In most of the organisms, there is a single posterior flagellum.
-Biflagellate zoospores with two whip types flagella of unequal length.
-Zoospores have one anterior flagellum of the tinsel type.
-Biflagellate zoospores with both whiplash(smooth) and tinsel type flagella attached anteriorly or laterally.

Note: Zoospores are also called a swarm spore. Zoospores may possess one or more distinct types of flagella that are tinsel and whiplash. The Tinsel flagellum is branched with many mastigonemes and is directed to the forward. The Whiplash flagellum is unbranched with an acute bend at the end and is directed anteriorly or posteriorly.