Evolutionary Evidence and Geological Processes

Evidence of Evolution

• Biogeographical: Isolated species evolve differently.
• Biochemical: A comparative study of molecules (DNA and proteins) of distinct species. When two species are evolutionarily closer, there is greater similarity in their molecular structure.
• Embryological: A comparative study of the development of different animal embryos. When two species are evolutionarily close, they share more developmental stages.
• Paleontological: The study of fossils (living beings or their activity). Intermediate forms indicate kinship relationships (the "missing link").

Geological Processes and Surface Modeling

Weathering and Erosion

Geological agents like wind and water cause the wear of reliefs. Erosion consists of shifting rock fragments (clasts) and detritus, producing characteristic relief forms and peneplains (large flat areas).

Sedimentation

The accumulation of material (detritus and sediment) in sedimentary basins (sunken areas) leads to the formation of sedimentary rocks.

Fluvial Modeling

Landforms produced by rivers include "V"-shaped valleys and meanders (curves in the river's route). Sedimentation results in the alternation of minerals and a reduction in clast size.

Aeolian Modeling

Produced by wind, particularly in warm deserts with low vegetation and dry soil. Processes include:

• Deflation: Wind removes smaller material, leaving larger fragments behind (stony deserts).
• Aeolian Abrasion: A sanding effect on rocks, creating mushroom-shaped boulders eroded at the base.
• Transport: Includes loess deposits (dust) and dunes (sand accumulation), such as barchans (crescent dunes).

Glacial Modeling

Large masses of ice act as geological agents in mountain valleys. Landforms include:

• "U"-shaped valleys (broad, deep, rounded profiles).
• Acute ridges (horns).
• Moraines: Accumulations of clasts (front, side, and background).
• Polished rocks, grooves, and dappled rocks (alom).

Karst Modeling

Surface and underground water acts on limestone (composed of calcite, CaCO₃), which undergoes solution via carbonation. Water filters to an impermeable rock level, creating specific relief forms:

• Lapiaz/Surco: Deep vertical grooves on the surface.
• Sima: Vertical shafts communicating with groundwater.
• Dolina: Circular surface depressions.
• Poljes: Large ground depressions.
• Torcal: Karst landscape formed by building collapse.
• Stalactites and Stalagmites: Formed by the precipitation of calcium carbonate on ceilings and floors, respectively.

Note: Chemical weathering (carbonation) is accelerated by water and high temperatures.

River Mouths

• Delta: A river mouth in waters without strong currents (e.g., Mediterranean Sea).
• Estuary: A river mouth in waters with strong currents (e.g., Atlantic Ocean).