Read Evolution in the Evidence
Evolution is supported by several independent evidence streams. Identify what each comparison actually shows.
Evolutionary Evidence is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Compare structure, not just function
Homologous structures share an underlying origin or plan even when their functions differ; vertebrate forelimbs are a classic example. Analogous structures perform similar functions but evolved independently, such as storage organs from potato stem and sweet-potato root. Atavisms are rare returns of ancestral traits.
Read fossils and embryos correctly
Fossils in deeper sedimentary layers are usually older than those above them. Transitional fossils such as Archaeopteryx combine traits that help reconstruct evolutionary transitions. Embryos can share early features, but development does not replay the adult stages of other species; biogeography is a separate evidence category.
OlympIQ exam lens
- ✓Homology: shared origin; analogy: similar function, independent origin.
- ✓Lower strata usually contain older fossils.
- ✓Archaeopteryx is a Jurassic transitional fossil.
- ✓Embryology and biogeography are distinct evidence types.
A shared function alone does not prove homology, and a fossil’s layer gives relative—not automatically exact—age.
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