AP Syllabus focus:
‘Geological and meteorological events change habitats and ecosystem distributions, as shown by biogeographical studies.’
Geological and meteorological events can rapidly or gradually reshape Earth’s surface and climate. These abiotic changes alter where organisms can live, shifting species ranges, reorganising communities, and creating biogeographical patterns observed across regions and through time.
Geological events and habitat change
Geological processes often act over long timescales, but can also be sudden and severe.
Tectonics, mountain building, and land bridges
Plate movements alter continental positions, elevation, and connectivity between landmasses.
Practice Questions
FAQ
They combine timing and pathways.
Geological dating (e.g., island age, uplift timing) compared with divergence-time estimates from genetic data.
Whether plausible routes existed (land bridges, stepping-stone islands) during the relevant period.
Mountains change conditions over short distances.
Temperature drops with altitude, and precipitation patterns shift (rain shadows). Steep gradients create distinct climate zones and limit dispersal across ridgelines.
Storms can act as dispersal vectors.
Rafting vegetation, windborne seeds, and transported insects can found new populations. Repeated colonisation can reshape island communities even when land area is unchanged.
Coasts are spatially constrained.
Small vertical sea-level shifts can move shorelines far horizontally, relocating beaches, salt marshes, mangroves, and estuaries, and fragmenting or connecting coastal habitats.
They preserve past community signals.
Pollen and charcoal layers indicate vegetation and fire history.
Microfossils and isotopes reflect temperature and moisture. These records can be matched to known climatic cycles to infer historical range shifts.
