Why do multicellular organisms use complex way of reproduction?

Multicellular organisms use complex ways of reproduction for various reasons, and the complexity of reproductive strategies is often tied to the specific ecological and evolutionary challenges faced by these organisms.

1. Genetic Variation: Complex reproductive strategies often involve the combination of genetic material from two parents, leading to offspring with genetic variation. Genetic diversity is crucial for the adaptability and survival of a population in changing environments. It provides a better chance for at least some individuals to possess traits that are advantageous in the face of environmental challenges.

2. Specialization Cells and Adaptation: Multicellular organisms often have specialized cells, tissues, and organs with specific functions. Complex reproduction allows for the transmission of specialized structures and functions to the next generation. This specialization enhances the adaptability of the species to diverse ecological niches and lifestyles.

3. emergence of new species over time: Sexual reproduction, in particular, can lead to the generation of unique combinations of genetic material, contributing to the evolutionary innovation and the emergence of new species over time.

4. Complex reproductive strategies: Complex reproductive strategies can be influenced by interactions with other species in the ecosystem. Symbiotic relationships, competition for resources, and predator-prey dynamics can shape the reproductive strategies of multicellular organisms.

5. Life History Strategies: Multicellular organisms often exhibit specific life history strategies, balancing factors such as reproduction, growth, and survival. The complexity in reproductive methods allows for the optimization of these life history strategies in response to environmental conditions.

In summary, multicellular organisms cannot reproduce by cell because they are not simple random collection of cells. In them, specialized cells are organized as tissues which are organized into organs. Cell-by-cell division would be impractical. Multicellular organisms, therefore, require to use more complex ways of reproduction.