Rhodobacter cells perform photosynthesis in the presence of light and grow heterotrophically in the dark. after being cultured in total darkness for multiple generations, phenotypic and genotypic changes occur. what phenotypic changes occur and what evolutionary processes are driving them?

Phenotypic changes:

When Rhodobacter is cultured in total darkness for multiple generations, the ability to produce it's own photopigment reduces with time with little or no ability to undergo its own photosynthesis due to absence of enzymes or pigment for photosynthesis.

It becomes expensive for the Rhodobacter to undergo photosynthesis. This allows mutants that can grow in the dark to take over from the culture grown in the dark.

Evolutionary processes:

It's natural selection that allows the fittest organism to survive. As in the case of the mutants

rocks and weathering-matching

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !