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Cells and Systems 6-8 / Week 02 / Nature Day
6/6
Week 02 · One Cell or Many

Nature Day

Nature Day: Where cells live
// Living things, from one cell to trillions
⏱ about 20 min

Nature Day: Where Cells Live

Saturday morning, the crew carries the hand lens into the garden. Raven stops at a damp, shady corner.

"What do you notice?" she asks. "Green fuzz on the stone. A spot of mold on an old leaf. A snail."

Rocket crouches. "The snail is many cells. The mold is a fungus, like yeast. What about the fuzz?"

"Moss," Raven says. "A plant, so many cells. But bacteria are here too, on every damp surface, far too small to see."

Nova hovers low over the soil. "Look, do not touch," she says. "Then wash your hands when you go in."

Rocket writes it down. "Living things everywhere. Some one cell, most many cells." Raven nods. "That is the whole week."

  1. Living things are made of one cell, like bacteria and yeast, or many cells, like plants, animals and you.
  2. The human body is composed of trillions of cells. In a multicellular organism, cells can be specialized.
  3. Yeast is a single-celled fungus. Given sugar it releases carbon dioxide, which inflated the balloon and makes bread rise.
  4. Cells are measured in micrometers, millionths of a meter. Plant and animal cells are 10 to 100 micrometers across.
  5. Individual cells are too small to see with the naked eye, so scientists use microscopes that magnify hundreds of times.
◇ FAMILY LOOK AT WHERE LIVING THINGS GROW
Walk a garden, park or yard together. Find three damp or shady places and three dry, sunny ones.
In each place, list the living things you can see: moss, mold, insects, plants, birds. Decide together: one cell or many?
Talk about what you cannot see. Bacteria live on almost every damp surface. Fungi grow where it is moist.
Back home, check the seed jar together, add water if needed, and measure the longest root.
For a grown-up
Outside, the crew looks at mold, insects, moss and soil from where they stand. Nothing is touched or picked.
Everyone washes hands after being outdoors or handling leaves and soil.
The facts in this week's recap come from the OpenStax biology textbooks at openstax.org and the National Library of Medicine at medlineplus.gov.
Safety first
Never touch mold, an insect, a nest or an unknown plant or berry. Look from where you stand.
Nothing found outside goes in your mouth.
Wash your hands when you come back inside.
THINK IT THROUGH
  • Read the question.
  • Tap your answer.
You see mold on an old leaf. Which is true?
Fungi grow best in which kind of place?
Nature Day checkTrue or false?
Bacteria live on damp surfaces even though you cannot see them.?
A snail is made of many cells.?
Moss is a single cell.?
WHY THIS EXERCISESorting real living things into one cell or many is the evidence the standard asks for.
Draw the damp corner your family found. Label each living thing "one cell" or "many cells".
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