Water Walkers: Neuston and Surface Tension

Which group of organisms is called neuston?

• Animals living on the water’s surface film

• Plants rooted in muddy stream bottoms

• Fish that swim deep below the surface

• Birds that dive for food underwater

What property of water mainly creates surface tension?

• Water molecules attract each other strongly

• Water is heavier than most liquids

• Waves push outward from shorelines

• Air presses downward on ponds

How does surface tension help small animals like water striders?

• A taut surface film supports their light bodies

• A thick ice layer keeps them from sinking

• A strong current carries them across lakes

• A sticky surface glues their feet in place

Which statement describes both a benefit and a hindrance of the surface film?

• It offers habitat but can trap prey for predators

• It warms water and speeds plant growth only

• It removes oxygen and harms all aquatic life

• It breaks easily and never supports organisms

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Match each term to its best description.

• Attraction among water molecules at the surface

• Top feeders

• Animals using the water’s surface as habitat

• Surface tension

• Fish feeding on insects at the surface

• Elasticlike film

• Taut layer that can support small organisms

• Neuston

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Which TWO features allow animals to seem to “walk on water”?

• Cohesion between water molecules

• Special adaptations of the organisms

• Heavy body weight pressing downward

• Hot temperatures reducing viscosity

Why might egg-laying mayflies near the surface increase feeding by some fish?

• The fish have mouths adapted to point upward

• The fish hide under rocks to avoid the sun

• The fish feed only at night in deep water

• The fish are attracted to loud water sounds

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Which adaptation lets water striders move across the water surface without sinking?

• Feet coated with water-repellent hairs and wax

• Gills that pull oxygen from lake water

• Flat tails used like underwater paddles

• Heavy claws that grip the muddy bottom

What is the main role of the long front legs of a water strider?

• Grabbing prey at the surface film

• Pushing like oars underwater

• Holding a bubble for breathing

• Sensing light reflections only

Water boatmen swim right-side up. How do their middle and hind legs help?

• Middle legs act like rudders; hind legs serve as oars

• Middle legs store air; hind legs hold prey

• Middle legs sense vibrations; hind legs cut plants

• Middle legs dig burrows; hind legs secrete wax