Evolutionary Changes in Microorganisms Due to Environmental Shifts

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In which type of environment does Rhodobacter carry out photosynthesis?

Dark aerobic environments

Dark anaerobic environments

Illuminated aerobic environments

Illuminated anoxic environments (correct)

What triggers pigment synthesis in purple bacteria like Rhodobacter?

Presence of O2 (correct)

Presence of carotenoids

Absence of light

Absence of carotenoids

How quickly can some microbial species produce a new generation?

20 minutes (correct)

1 hour

1 day

30 minutes

What is the primary role of bacteriochlorophyll and carotenoids in purple bacteria?

Participate in photosynthetic reactions Signup and view all the answers

What provides the raw material upon which natural selection acts in microbial populations?

Heritable variations Signup and view all the answers

"New Traits Can Evolve Quickly in Microorganisms" refers to which evolutionary phenomenon?

"Saltation" effect Signup and view all the answers

What major breakthrough did one of the evolved lines achieve after 31,500 generations?

Ability to use citrate as an energy source Signup and view all the answers

Why was citrate not considered a potential carbon source for E.coli in the experiment?

E.coli lacked the necessary genes to metabolize citrate. Signup and view all the answers

What was the impact of mutations in the evolved line that gained the ability to grow on citrate?

They allowed for the evolution of a new adaptive trait. Signup and view all the answers

What does the fact that only one of the 12 parallel lines evolved the ability to grow on citrate demonstrate?

The chance nature of evolution. Signup and view all the answers

How did Rhodobacter's mutation that was deleterious in the wild become advantageous in the laboratory environment?

It provided a selective advantage under dark conditions. Signup and view all the answers

What effect did evolution have on Rhodobacter's metabolic machinery under new laboratory conditions?

It resulted in loss of unneeded metabolic machinery. Signup and view all the answers

What do high bootstrap values indicate in a phylogenetic tree?

Nodes are likely to be correct Signup and view all the answers

What does low bootstrap values in a phylogenetic tree suggest?

Nodes placement cannot be accurately determined Signup and view all the answers

What is homoplasy also known as in the context of evolution?

Convergent evolution Signup and view all the answers

How can the number of nucleotide differences between gene sequences be utilized in building a phylogenetic tree?

By creating a distance matrix Signup and view all the answers

What does a distance matrix indicate in the context of building a phylogenetic tree?

Number of nucleotide differences between gene sequences Signup and view all the answers

Why is it challenging to choose the true tree in phylogenetics based on available sequence data?

Several different trees fit the data equally well Signup and view all the answers