Q17 - Genome Streamlining Tracks Niche Specialisation in Marine Cyanobacteria

Theoretical B Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Molecular Evolution & Neutral Theory Ecology

Scientists are uncertain how Natural Selection shapes genome size, gene number, physiological flexibility and other important features in response to environmental pressures. Ecological and genetic characteristics of four species of marine cyanobacteria are listed in the table. Prochlorococcus are the most abundant cyanobacteria on earth. The Prochlorococcus lineage evolved from Synechococcus. Synechococcus Prochlorococcus Prochlorococcus Prochlorococcus eNATL eMED4 eMIT Depth at which found Very deep Deep Shallow Shallow Region in which found Global Global Poles Equator Ability to tolerate low nutrient conditions Cannot tolerate Can tolerate Can tolerate Can tolerate

Figure 1 for Q17: Genome Streamlining Tracks Niche Specialisation in Marine Cyanobacteria

Using the information and data, determine which of the statements are true or which are false.

A. A species requires more genes to specialise to a new habitat.

B. Prochlorococcus species can tolerate low nutrient conditions because they have more genes with which they can utilise their environment.

C. Intense equatorial sunshine drove the evolution of light tolerance.

D. Measuring genome size can be used to estimate the number of genes Prochloroccous has.

← Previous: Q16 Next: Q18 →

Question reproduced from IBO 2017, Theoretical Exam B, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Official answer key & worked solutions