Final answer:
Spirogyra can reproduce through fragmentation, a process where each broken piece of the algae can grow into a new organism. This asexual reproduction method is common in many multicellular organisms, allowing for rapid population growth and resilience in various environments.
Step-by-step explanation:
New Spirogyra can be grown from pieces of an existing organism due to certain reproductive strategies in multicellular and colonial organisms, such as fragmentation and regeneration. Spirogyra, a filamentous algae, can reproduce asexually by fragmentation. When a fragment of Spirogyra breaks off, each piece contains cells that are capable of growing into a new filament, making fragmentation an efficient means of reproduction for this organism. This process is common in multicellular or colonial organisms that do not rely solely on the proliferation of a single cell, such as a zygote or spore, for reproduction.
Other organisms also utilize similar strategies, such as starfish in marine environments, which can regrow from a single arm. This mode of reproduction is advantageous in that it allows a rapid increase in population size and can occur naturally or in response to environmental pressures. In the case of cellular slime molds, which are used as model organisms in genetic studies, this type of reproduction may shed light on the evolution of multicellularity in organisms.