How Animals Move - First Grade Science
Animals live in an active, exciting world where they must move every single day to find food, seek clean drinking water, escape danger, and locate cozy shelters. While plants remain rooted in one spot, animals possess muscles, bones, and specialized limbs that allow them to travel in amazing ways. Depending on where an animal lives and what its body looks like, it might run swiftly on legs, swim gracefully through deep waters, fly high across the sky, hop along grassy meadows, or slither smoothly along the ground.
Moving on Land: Walking, Running, and Crawling
Land animals have developed strong legs and feet adapted to move across soil, sand, rocks, and snow.
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| LOCOMOTION ON LAND |
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| TWO LEGS (Bipedal) FOUR LEGS (Quadrupedal) |
| - Humans walk and run upright. - Dogs, cats, horses, deer. |
| - Birds walk and hop on two legs. - Spreads weight evenly; fast. |
| - Free front limbs for holding. - Hoofs, paws, padded claws. |
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Fast Runners of the Wild
Cheetahs are the fastest land runners on Earth, reaching highway speeds in just three seconds! They have long, flexible backbones that bend like springs, muscular legs, and non-retractable claws that grip the ground like athletic cleats. Horses have single-toed hooves made of hard keratin that absorb shock when galloping across plains.
Creeping and Crawling
Insects like beetles and ants have six jointed legs that move in a coordinated tripod pattern, keeping three legs on the ground at all times for rock-solid stability. Spiders use eight legs to scurry across walls and balance on delicate silk webs.
Leaping and Hopping
Some animals do not walk step-by-step; they launch themselves through the air in powerful jumps!
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| POWERFUL HOPPERS |
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| FROGS & TOADS KANGAROOS & RABBITS |
| - Long, muscular back legs - Huge feet and stretchy tendons|
| - Folded like springs at rest - Bounce with elastic energy |
| - Leap many times body length - Balances with large tail |
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Elastic Tendons
A kangaroo's long hind legs act like giant rubber bands. When a kangaroo lands from a hop, its leg tendons stretch, storing energy. When it pushes off again, that energy snaps back, propelling the kangaroo forward across dry Australian grasslands without wasting much muscle power.
Flying: Gliding and Soaring in the Air
Moving through the air allows animals to cover vast distances quickly and escape ground-dwelling predators.
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| FLYING CREATURES |
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| BIRDS BATS FLYING INSECTS |
| Feathered wings; Webbed skin stretched Thin, vein-strengthened |
| light hollow bones across long finger bones wings beat thousands of |
| flap to create lift flap in agile flight times every minute |
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How Wings Create Lift
Birds fly by flapping their wings up and down. A bird's wing is curved on top and flat underneath. As the wing moves forward, air flows faster over the curved top, creating low pressure that lifts the bird into the sky. Hummingbirds can flap their wings up to eighty times per second, allowing them to hover in midair like helicopters and even fly backward!
Swimming: Moving Through Water
Water is much thicker than air, so aquatic animals require streamlined, torpedo-shaped bodies that cut cleanly through currents.
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| SWIMMING MECHANICS |
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| FISH MARINE MAMMALS WATER BIRDS & FROGS |
| Fins and muscular Dolphins & whales flap Ducks and frogs paddle |
| tail sweep side- broad horizontal tails using webbed feet like |
| to-side in water. up-and-down. oars on a boat. |
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Fins and Webbed Feet
Fish use their caudal (tail) fin to generate forward thrust, while pectoral and pelvic fins provide balance, steering, and braking. Ducks have thin skin stretched between their toes, called webbed feet. When a duck pushes backward, the webbed toes spread wide to push a large volume of water; when it pulls its foot forward, the toes fold together to reduce drag.
Slithering: Moving Without Limbs
How does an animal move if it has no legs, wings, or fins? Snakes and earthworms demonstrate how muscles alone can create rapid movement.
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| SLITHERING (SNAKES) |
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| _..._ |
| .' '. |
| / S- \ <--- LATERAL UNDULATION |
| | SHAPE | Curves push against ground bumps, |
| \ / pebbles, and twigs to propel forward. |
| '-..._.-' |
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A snake contracts bands of muscles along its sides, bending its flexible spine into S-shaped waves. The wide, rough belly scales grip microscopic rough spots in the soil, pushing the snake forward with surprising speed and silence.
Chapter Review Exercises
Question 1: Why do animals need to move around in their environments? State three reasons.
Question 2: How do webbed feet help water birds like ducks swim efficiently in lakes and ponds?
Question 3: Describe how a snake is able to travel across the ground even though it has no legs.
Question 4: What body features enable birds to achieve flight in the sky?
Solutions and Explanations
Solution 1: Animals need to move around to find nutritious food, locate clean drinking water, escape from predators and danger, find safe shelters, and seek mates to raise offspring.
Solution 2: Webbed feet have skin stretched between the toes that acts like boat oars. When the bird kicks backward, the webbing fans out to push against a large amount of water for propulsion; when pulling the leg forward, the toes collapse to glide smoothly.
Solution 3: A snake moves by flexing muscles along its spine into S-shaped curves (lateral undulation). The edges of its wide belly scales catch against small bumps, sticks, and pebbles on the ground, pushing the snake forward.
Solution 4: Birds can fly because they have lightweight hollow bones, powerful chest muscles, curved aerodynamic wings covered in smooth flight feathers that generate lift, and streamlined body shapes.