Subscribe

7th grade · Science · Unit 9 of 18

Food Chains & Energy

Who eats whom, and the energy

What your child practices

Producers, consumers and decomposers, food chains and webs, how energy shrinks as it passes up a chain (about 10% each step), and what happens when part of a chain changes.

Texas Essential Knowledge and Skills (TEKS) teks student expectation: 7.12(A); 7.12(B) · energy flow through trophic levels, and matter recycling in ecosystems

How we explain it

Children can open this short lesson before they practice.

  1. Producers make food from sunlight. Consumers eat other living things. Decomposers break down dead matter.
  2. Arrows in a food chain point from the food to the eater.
  3. Only about 10% of the energy at one level passes to the next.

Example: Plants store 1000 units of energy. About how much reaches the rabbits that eat them? About 10% passes on. 10% of 1000 is 100. Answer: 100 units

Food Chains & Energy in Texas

In the Texas Essential Knowledge and Skills (TEKS), this is unit 9 of 18 in 7th grade Science, after Natural Selection and before Human Body Systems.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Texas Education Agency (TEA)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    In a food chain, what do the arrows show?

    • How old each organism is
    • The direction that energy flows
    • Which animal is larger
    • Where each organism lives

  2. Question 2

    Producer, consumer or decomposer? Sort each organism.

    Sort into: 🌿 producer · 🐇 consumer · 🍄 decomposer

    • 🍞bread mold
    • 🟢algae in a pond
    • 🍄a mushroom on a log
    • 🍁a maple tree
    • 🦗a grasshopper
    • 🦅a hawk

  3. Question 3

    Why is a food web often more stable than a single food chain?

    • It has no producers to run out
    • It has no top predators
    • Consumers can switch to another food source if one declines
    • Each animal eats only one thing

  4. Question 4

    Grass stores 20,000 units of energy. About 10% of the energy at each feeding level is passed on to the next. How many units reach the grasshoppers that eat the grass?

    answer boxunits

  5. Question 5

    Only about 10% of the energy passes to the next feeding level. What happens to the rest?

    • It turns into producers
    • Most is used for life processes or lost as heat
    • It disappears for no reason
    • It is stored for the next level to use later

  6. Question 6

    Put this food chain in order, from the organism that makes food to the last to eat.

    • 🐍snake
    • 🦗grasshopper
    • 🦅hawk
    • 🌾grass

More 7th grade