Scientists originally thought cell membranes evolved before RNA. However, recent evidence suggests RNA developed before the membranes that envelop it. Explain why this is logical in light of the composition and function of both RNA and membranes.

The need for replication, specialization, compartmentalization is key to understand that RNA evolved first

Explanation:

Logical contrast considering a certain catalytic activities of cardinal importance in the early evolution of life ;

• using an RNA molecule that is involved in to catalyzing the process of templated polymerization –selecting a random RNA molecule as a template.

• the ribozyme activity in this process must have engaged an in vitro process in a body part that no longer has a function such that it that can only synthesize moderate lengths of RNA

• when this molecules acts on the copies of itself can replicate

• when it acts on copies of other type of RNA molecules in its surrounding he can promote their replication

• a cooperative system might have evolved from the neighbors to help the survival of this friendly RNA molecules – through catalytic actions, such that a set of different types of RNA molecules evolves with a mark of specialization for different activity.

The development of individual compartments is proposed to be akin to the effective self-replicating systems.

• If RNA molecules are mutually beneficial they may serve the purposes of being specialized for templated polymerization.

• If these RNAs were free to diffuse among a large population of other RNA molecules, they could be assimilated into an established group by other replicating systems, which in turn may compete with the original RNA system for raw materials.

• The quality of the self-replicating systems they generated relies on the compartment that restricts the RNA molecules only to the system they serve.

• compartments started simply and perhaps had simple adsorption on surfaces or simple particles.

• compartmentalization became complex requiring a class of small molecules with varying physicochemical properties liike being amphipathic.

• This gave rise to the phospholipids mainly and the present-day cells often are coated by a plasma membrane consisting of amphipathic molecules in this configuration.

the genotypes would be 50% bb and 50% bb

the phenotypes would be 50% brown and 50% white. hope this : )