Wind affects organisms on land in several ways:
• Water loss. Wind blows away the layer of moist air next to leaves, increasing the water potential gradient, so the rate of transpiration increases. Plants in exposed, windy places such as coasts and mountains often have xerophytic features, such as small leaves or hairs that trap still air.
• Cooling. Wind increases heat loss by convection and evaporation (wind chill), which is a problem especially for small animals.
• Physical damage. Strong winds break branches and uproot trees. Trees on exposed coasts and hills are often stunted and bent away from the prevailing wind.
• Dispersal. Many plants depend on wind for pollination and for dispersal of seeds and spores, and small insects and spiders can be carried long distances.Water currents in rivers, streams and on shores have similar effects:
• Organisms must avoid being swept away. Invertebrates in fast streams are often flattened (such as mayfly nymphs) or cling on with suckers or hooks; limpets clamp tightly to rocks on wave-battered shores; fish such as trout are streamlined, strong swimmers.
• Few rooted plants can grow in fast water, but algae and mosses attach to stones.
• Fast, turbulent water mixes air into the water, so it is well oxygenated.
• Currents carry food particles to filter feeders, such as mussels and blackfly larvae, and disperse larvae and gametes.So the speed of the current largely decides which species live in different parts of a river.
• Water loss. Wind blows away the layer of moist air next to leaves, increasing the water potential gradient, so the rate of transpiration increases. Plants in exposed, windy places such as coasts and mountains often have xerophytic features, such as small leaves or hairs that trap still air.
• Cooling. Wind increases heat loss by convection and evaporation (wind chill), which is a problem especially for small animals.
• Physical damage. Strong winds break branches and uproot trees. Trees on exposed coasts and hills are often stunted and bent away from the prevailing wind.
• Dispersal. Many plants depend on wind for pollination and for dispersal of seeds and spores, and small insects and spiders can be carried long distances.Water currents in rivers, streams and on shores have similar effects:
• Organisms must avoid being swept away. Invertebrates in fast streams are often flattened (such as mayfly nymphs) or cling on with suckers or hooks; limpets clamp tightly to rocks on wave-battered shores; fish such as trout are streamlined, strong swimmers.
• Few rooted plants can grow in fast water, but algae and mosses attach to stones.
• Fast, turbulent water mixes air into the water, so it is well oxygenated.
• Currents carry food particles to filter feeders, such as mussels and blackfly larvae, and disperse larvae and gametes.So the speed of the current largely decides which species live in different parts of a river.