Traits: inherited and environmental

Activities to try

1. 1

   Same genes, different lives: grow-and-compare investigation

   Why it works: When genetically identical organisms (clones) are raised with just one condition deliberately changed and everything else held constant, a clear difference that emerges is best explained by the environment, not inheritance. This controlled contrast is the evidence that supports the claim [curriculum wording omitted; reference 3-LS3-2].

   1. Take two cuttings from ONE parent plant and label them as identical clones with the same inherited information ('same parent, so the same genes').
   2. Pot them separately and change only ONE condition between them — for example, keep the water the same for both but put one in bright light and the other in a dim spot (or keep the light the same for both and give one plenty of water while the other gets much less). Keep everything else identical.
   3. Before growing, predict in writing or speech whether the two plants will end up the same or different, and state WHY.
   4. Grow them over time (or use a time-lapse/paired before-after images), then compare the outcome: e.g. in the light test, one bushy and green, one thin, leggy and pale; in the water test, one lush, one small and wilted.
   5. State the conclusion in your own words and give the reason: 'The plants are clones with the same inherited information, and only one condition was changed, so the clear difference is best explained by the environment (the condition we changed).'
2. 2

   Three-bin trait sorter: inherited, environmental, or both

   Why it works: Traits are not all one kind: some are mainly inherited, some are caused by the environment, and many — like height and size — come from an inherited potential shaped by the environment. The 'both' category is where real understanding shows.

   1. Sort a pile of traits into three bins — inherited, environmental, and BOTH — and write a short reason for each placement.
   2. Place clear cases: eye colour and natural coat colour (mainly inherited); a scar, a suntan, and plant stunting from drought (environmental).
   3. Place 'both' cases such as height, body size, and muscle: explain that there is an inherited potential that is then shaped by nutrition or exercise.
   4. For each 'both' trait, state one way inheritance contributes and one way the environment contributes.
   5. Compare animal and plant examples side by side (plant height/colour; animal weight/muscle) so environmental influence is seen as general.
3. 3

   Predict the change and test for inheritance of acquired traits

   Why it works: Predicting outcomes from a change in conditions reinforces environmental causation, and separating 'a trait changed in one individual' from 'what is passed to offspring' corrects the Lamarckian belief that acquired changes are inherited.

   1. Predict how a trait changes when conditions change: less water → stunted plant; more food and less exercise → heavier dog; regular exercise → more muscle.
   2. For an animal lane, compare an overfed, under-exercised puppy with a well-exercised one and describe the difference and its environmental cause.
   3. Answer the inheritance question for an acquired trait: 'A weightlifter has huge muscles — will their children be born with huge muscles?' Explain your reasoning.
   4. Answer: 'Could the big sunny plant pass its bigness on to cuttings taken from it, if those cuttings then grow in the dark?' Explain.
   5. State the general rule in your own words: environmentally-caused (acquired) changes affect that individual but are not passed on to offspring.