Extinction means that no living members of a species remain. Natural selection needs heritable variation and differences in reproduction over generations. It cannot guarantee a helpful trait appears in time. Moving or changing behaviour may help some populations, but these options can be blocked. Safety: Paper cases only; no wildlife visits or fishing equipment. Stop: Stop after comparing evidence. Do not seek wildlife, nets or current census data for this task.

Materials: Paper; Pencil 1. Copy two evidence cards: Historical—Mauritius’s dodo disappeared after human arrival; hunting and introduced animals contributed. Contemporary—vaquitas in the northern Gulf of California face accidental capture in gillnets. Keep the cases separate and do not invent current population counts. 2. For each case draw pressure → survival or reproduction problem → fewer possible parents. Write why being well suited to an earlier environment does not ensure survival after a rapid new pressure. 3. Copy this illustrative population case: ten animals have no inherited ability to survive repeated net entanglement; all die before reproducing. Explain why the animals cannot choose a useful mutation and why future selection cannot rescue a population with no survivors. 4. Make two definitions: background extinction is the ongoing lower rate of species loss between major crises; mass extinction is unusually widespread, large species loss in a geologically short interval. Add habitat destruction, hunting and climate change as human-driven pressures, with one mechanism for each. Done: The comparison contains both named cases, a rapid-change explanation and the background/mass distinction. Proof: Keep the two-case diagram and definitions. Note adult help with the extinction mechanism or case reading. Stop: Stop after comparing evidence. Do not seek wildlife, nets or current census data for this task.