Evolution

Study the lesson, practice with the interactive tasks, and then test yourself with real Olympiad questions from past years. For each lesson, we list the exact Olympiad question(s) you’ll be ready to answer.
 

Origin of Life
Olympiad questions you’ll be ready to answer:

• Explain why early Earth conditions assumed a reducing atmosphere.

• State the goal of the Miller-Urey experiment and its key constraints.

• List distinguishing predictions for four origin-of-life hypotheses.

• Arrange major transitions leading to first cells by causal order.

• Identify limiting factors in laboratory simulations of prebiotic chemistry.

Evolution of Life on Earth

Olympiad questions you’ll be ready to answer:

• Match fossils to the most accurate reconstruction using structural criteria.

• Explain environmental and biological factors that influence fossil preservation and how this shapes representation of past flora and fauna.

• From a rock layer description containing fossils, deduce the likely habitat and ecological conditions the organisms lived in.

• Determine which fossil traits help narrow a geological period when absolute age data are not available.

Symbiosis
Olympiad questions you’ll be ready to answer:

• A host and its partner are described without names. Use the description to determine the type of symbiosis. Justify your classification based on effects on the fitness of both participants.
• Life cycle hints are given. Deduce whether the symbiont transmission is most likely vertical, horizontal, or mixed.
• A new symbiotic system is described. Predict what resource is most likely exchanged between partners to maintain stability.
• Obligate and facultative relationships are characterized in the prompt. Explain the criteria used to differentiate them.
• Genomic or structural clues are provided. Infer if they support a long-term intracellular partnership or a transient external association.
• Detection of evolutionary cheating: identify behaviors or traits suggesting possible exploitation by one partner, and propose evidence-based mechanisms for host control or sanctions.

Symbiogenesis
Olympiad questions you’ll be ready to answer:

• A cell compartment is described with membranes and genome data. Decide if it is an organelle of endosymbiotic origin or not. 
• Three or four membranes are shown around a plastid-like structure. Explain which evolutionary events could lead to this membrane count.
• Given a description of metabolic dependency between host and endosymbiont, predict fitness consequences of losing the symbiont.
• Identify experimental or interpretive pitfalls when using modern organisms to model ancient symbiogenesis.
• Compare primary and secondary intracellular symbiotic acquisitions using prompt clues such as membrane structure, metabolic autonomy, and genome retention.