One parent or two: how living things reproduce

Grade 7 Science Worksheet

Circle the best answer.

1. 1.

   Ari plants a piece of potato tuber, an underground stem, with a sprouting eye. The new potato plant grows. How do its genes compare with the plant the tuber came from?

   • They are halved, since the tuber is a piece of a plant
   • They are a new mix, since the sprout joined cells from two plants
   • They differ, since the new plant grew in new soil
   • They match, since one plant made the new plant
2. 2.

   Bo watches a bee carry pollen from one sunflower plant to a different sunflower plant. Sperm and egg cells join, and seeds form. How do the seedlings’ genes compare with the two plants?

   • Each seedling has half as many genes as its parents
   • Each seedling is a copy of the plant that gave the pollen
   • Each seedling has a new mix of genes from both plants
   • The seedlings match each other, with the same genes
3. 3.

   Esme reads a chart for two parent birds. Their sperm cell and egg cell join. What goes in the Offspring box?

   • New genes unlike either parent
   • Genes set C alone, matching the second parent
   • A mix of genes set B and genes set C
   • Genes set B alone, matching the first parent
4. 4.

   Jun reads that a ginger plant grows a new shoot from its underground stem, a rhizome. The shoot becomes a new plant. Is this asexual or sexual reproduction, and why?

   • Sexual, because the shoot needs a partner plant
   • Asexual, because one parent makes the new plant
   • Sexual, because a new plant is a new living thing
   • Asexual, because the offspring differ from the parent
5. 5.

   Kira reads that a hummingbird carries pollen from a red flower to a flower on a different plant. Seeds form. Is this asexual or sexual reproduction, and why?

   • Sexual, because each seed copies the pollen plant
   • Asexual, because plants make seeds from one flower
   • Asexual, because a bird just moves the pollen
   • Sexual, because sperm in the pollen joins an egg cell of another plant
6. 6.

   Luz grows a tray of seedlings from seeds made when pollen from one plant reached the flower of another plant. The seedlings differ from each other. How were they most likely made?

   • Asexual reproduction, because offspring copy their parent
   • Sexual reproduction, because each seedling copies one parent
   • Sexual reproduction, because two parents mixed their genes
   • Asexual reproduction, because one parent changes its genes each time
7. 7.

   Noah reads about three seeds. Which seed is most likely to be carried on an animal’s coat?

   • No seed, because seeds stay where they form
   • Seed L, because light seeds hitch a ride on fur
   • Seed K, because its wing-like parts grip a coat
   • Seed J, because its hooks cling to a coat
8. 8.

   Pia reads about two bird behaviors in spring. Which pair of jobs matches them?

   • Song holds eggs and young; the nest draws a partner
   • Song draws a partner; the nest carries seeds away
   • Song draws a partner; the nest holds eggs and young
   • Song carries seeds away; the nest carries pollen
9. 9.

   Ren’s garden stays the same year after year. Which is an advantage of asexual reproduction there?

   • Offspring change their genes to suit the garden
   • The new plants reach maturity more slowly than seedlings
   • Offspring match a parent that already does well there
   • Offspring get a new mix of genes from two parents
10. 10.

    Zee compares the two ways of reproducing. Which is a cost of sexual reproduction?

    • Offspring cope less well when conditions change a lot
    • Offspring share the same weakness when the weather changes
    • Offspring are exact copies of one parent’s genes
    • A parent must find a partner, which takes time and energy