Question

Which of the following must a primitive cell contain so that it may survive and evolve according to principles of Darwinian evolution?

1) The surface area becomes limiting as a cell increases in size
2) The distance between the cell surface and interior becomes too great for the cell's needs to be met by simple diffusion
3) Their nuclei possess a limiting number if copies of each gene
4) Biological energy is not sufficient for a larger cell

Answer 1

A primitive cell must maintain an efficient surface area-to-volume ratio to facilitate diffusion for survival and evolution. Adaptations like membrane folding and organelle development in eukaryotic cells help maintain this efficiency as cells grow.

Step-by-step explanation:

For a primitive cell to survive and evolve according to Darwinian evolution principles, it must maintain a surface area-to-volume ratio that allows for efficient diffusion of nutrients and waste. As the cell increases in size, its surface area grows arithmetically while its volume increases geometrically, according to the formulas surface area = 4πr² and volume = 4/3πr³. If a cell grows too large without adequate surface area, it will be unable to support the necessary rate of diffusion, leading to inefficiency and likely cell death or the need to divide.

Cells can adapt by increasing surface area through membrane folding, becoming flattened or adopting elongated shapes, or through the development of organelles that help to perform specific tasks. These adaptations are part of the sophisticated structures found in eukaryotic cells and are essential for supporting life functions as the cell grows.

This adaptation and efficiency are crucial for a cell's survival and give it the potential to evolve over time, as outlined by evolutionary theory which includes Darwinian principles. Cells that cannot efficiently transfer substances in and out due to size constraints may not be viable, leading to natural selection favoring cells that maintain optimal size and shape for diffusion.