# Two held new model briefs

Teacher keeps these sources separate from ordinary teaching until Days 25/30. No completed response, prior trial, population count or learner output is supplied. Choose one component now; others can wait for another sitting. Use a diagram, words, sign, AAC, broad labelled positions or directions for a named adult. A plan is welcome. Give your own scientific choices; physical handling, handwriting or speech is not required.

## FW-C · New hypothetical pond model · Day 25

**Original invented teaching model, not an observed pond or verified species diet.** Nodes: P = Producer; R = Grazer R; T = Grazer T; H = Hunter H. The source stipulates feeding relationships **P→R; P→T; R→H; T→H**. Each arrow goes from food resource to consumer and represents transfer of some matter and chemical energy through feeding.

**New condition:** Less light is stipulated to reduce production by P; other listed starting conditions stay the same. No later population result, quantities or previous trial is supplied. Reduced production is not a supplied population count.

Choose a start:

- Represent or describe one or more supplied links and explain your arrow meaning.
- Choose a population and explain one possible later effect of this condition, with a reason and condition/unknown. Other justified answers are possible.
- Ask a question that would help compare predictions, or add a distinction between matter and energy if useful.

First response space/record: **blank**. Another component can wait. The teacher will read your exact source again if requested; no answer is printed.

## FW-D · New hypothetical multi-path model · Day 30

**Original invented teaching model, not an observed ecosystem or verified species diet.** Nodes: M = Producer M; N = Producer N; A = Consumer A; B = Consumer B; H = Hunter H. The source stipulates feeding relationships **M→A; N→A; M→B; A→B; B→H**. Each arrow goes from food resource to consumer and represents transfer of some matter and chemical energy through feeding.

**New condition:** The population of B decreases as a hypothetical input. No later population result is supplied. There are no population quantities or previous learner trials in this source.

Choose a start:

- Represent or describe one or more supplied links and explain your arrow meaning.
- Choose a population and explain one possible later effect of B decreasing, with a path/mechanism and condition or uncertainty.
- Give an alternative effect or a question that could change your answer. You need not assign a direction to every node.

First response space/record: **blank**. A different justified conditional answer is welcome. Your first response stays separate from later help or revision; return another sitting if wanted.