Final answer:
Savannas are defined by a prevalence of grasses and forbs with few scattered trees, adapted to survive fires in hot, tropical climates with a distinct wet and dry season. Fire resistance and the C4 photosynthetic pathway in grasses contribute to their dominance in this biome.
Step-by-step explanation:
Savannas are tropical grasslands with a mix of grasses, forbs, and scattered trees. They are characteristic of regions in Africa, South America, and northern Australia. Dominant plants in savannas include various grass species and herbaceous flowering plants known as forbs.
Due to frequent fires during the extensive dry season, savanna plants have developed robust root systems that enable them to quickly resprout following a fire.
This adaptation helps maintain the grass-dominated landscape, as trees are less prevalent due to their susceptibility to fire and lower competition under high temperatures and variable rainfall.
The dominance of grasses in savannas is further reinforced by the existence of the C4 photosynthetic pathway in many grass species.
This pathway allows for efficient growth in hot and sunny climates, particularly under low atmospheric CO₂ concentrations.
Fire also plays a critical role in the savanna ecosystem by preventing the encroachment of woody plants and maintaining the grassland dynamic.