Life Processes in Animals: common misconceptions

If your child says… “Digestion starts in my stomach.”

Ask together

If it tastes sweeter, where did that change begin?

What’s true

Digestion begins in the mouth.

If your child says… “My stomach absorbs most food nutrients.”

Ask together

Which organ has the arrows carrying nutrients into blood?

What’s true

Most digested nutrients enter blood through the small-intestine wall.

If your child says… “That grass never left its mouth.”

Ask together

Was this food kept in the mouth, or swallowed and brought back?

What’s true

The cow swallowed it earlier.

If your child says… “Hens chew grain with their beaks.”

Ask together

Where do the squeezing arrows act on the food?

What’s true

The gizzard grinds swallowed food; the beak does not chew it.

If your child says… “My diaphragm rises when I breathe in.”

Ask together

Would an upward-moving diaphragm leave more room for your expanding lungs?

What’s true

Your diaphragm moves down inside your chest, beyond what your hands can feel.

If your child says… “I breathe out only carbon dioxide.”

Ask together

Does taking some oxygen mean taking all of it?

What’s true

Breathed-out air remains a mixture because blood takes up only some oxygen.

If your child says… “Breathing and respiration are the same.”

Ask together

Where must the food’s energy be released?

What’s true

Moving air does not itself release food energy.

If your child says… “Underwater animals need no oxygen.”

Ask together

What would gills supply if fish needed no oxygen?

What’s true

Animals need oxygen whether they use gills, lungs or moist skin.