Conservation: Small Populations, Fragmentation and Reserve Design · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Small, split, and worth connecting

Science · Ecology & Conservation · ages 21-22
Name ______________________   Date ____________

  1. Why can one storm erase a small population but only dent a large one?

    • Small groups hold no spare numbers or genes
    • Storms avoid large habitats
    • Large animals resist all weather

  2. Which two genetic risks stalk small populations?

    • Extra rainfall and rich soil
    • Migration and mutation supply
    • Inbreeding and random drift

  3. Edge zones of a fragment run hotter, drier, and more predator rich than interiors.

    Circle one:   True   False

  4. A road splits a forest in half but clears little ground. Why is the harm large?

    • Roads always plant new trees
    • Animals prefer living beside roads
    • The road adds long edges and stops migrants crossing

  5. How do the two small-population risks reinforce each other?

    • Drift donates fresh genes from neighbours
    • Falling numbers deepen inbreeding, which weakens survivors and shrinks numbers further
    • Inbreeding raises the birth rate

  6. Two reserves hold equal area: one round block, one thin strip. Which shelters interior species better?

    • The round block, since little edge guards a calm interior
    • The thin strip, since edges feed animals
    • Both equally, since area alone decides

  7. A corridor joining two patches helps because migrants carry fresh genes and recolonists.

    Circle one:   True   False

  8. A planner paves half a reserve but keeps the total area by adding a far corner elsewhere. What is the flaw?

    • Area is all that matters, so nothing is wrong
    • Splitting trades interior for edge and breaks connection
    • New corners always hold more species
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Small, split, and worth connecting W1-mt_yOl2NGoLeb-s1

  1. Small groups hold no spare numbers or genes · With no buffer of numbers or variation, a single bad event finishes the group.
  2. Inbreeding and random drift · Inbreeding weakens survivors while drift randomly fixes harmful variants.
  3. True · Exposure reaches inward from every cleared boundary.
  4. The road adds long edges and stops migrants crossing · Two new edges degrade interiors while isolation blocks rescue and recolonisation.
  5. Falling numbers deepen inbreeding, which weakens survivors and shrinks numbers further · Fewer breeders mean closer mating, weaker young, and even fewer breeders next round.
  6. The round block, since little edge guards a calm interior · Round shapes minimise edge for the area, keeping true interior alive.
  7. True · Connection fights both isolation harms: inbreeding and failed recolonisation.
  8. Splitting trades interior for edge and breaks connection · Equal area cannot repay lost interior and severed movement between patches.
Worksheet · LightMySky