Science Worksheet (Set 6)
Topic: Reproduction and Genetics
Q1. Answer the following questions:
a. Compare seed dispersal by wind and seed dispersal by animals.
| Feature | Seed Dispersal by Wind | Seed Dispersal by Animals |
|---|---|---|
| Seed Characteristics | Lightweight, winged, or feathery seeds. | Large, fleshy, or sticky-coated seeds. |
| Mechanism | Carried away by the wind due to their lightweight structure. | Animals eat the fruit and excrete the seeds, or seeds attach to animal fur and are carried to new locations. |
| Example | Dandelion, Cotton | Mango, Guava |
b. Critique the statement: “Cross-pollination is always better than self-pollination.” Write reasons for your opinion.
Advantages of Cross-Pollination:
– Produces genetically diverse offspring, increasing adaptability to environmental changes.
– Reduces the risk of genetic disorders caused by inbreeding.
– Leads to healthier and more vigorous plants.
When Self-Pollination is Beneficial:
– Ensures reproduction when pollinators are scarce.
– Maintains desirable traits in a stable environment.
Conclusion: Cross-pollination is usually better, but self-pollination is advantageous in certain conditions.
– Produces genetically diverse offspring, increasing adaptability to environmental changes.
– Reduces the risk of genetic disorders caused by inbreeding.
– Leads to healthier and more vigorous plants.
When Self-Pollination is Beneficial:
– Ensures reproduction when pollinators are scarce.
– Maintains desirable traits in a stable environment.
Conclusion: Cross-pollination is usually better, but self-pollination is advantageous in certain conditions.
c. Why is DNA called the blueprint of life?
– DNA contains genetic instructions for the growth, development, and functioning of all living organisms.
– It carries hereditary information from one generation to another.
– It determines the traits and characteristics of an organism by coding for proteins.
– It carries hereditary information from one generation to another.
– It determines the traits and characteristics of an organism by coding for proteins.
d. Why are flowers like hibiscus considered complete flowers while corn flowers are not?
– A complete flower has all four floral parts: sepals, petals, stamens, and carpels.
– Hibiscus is a complete flower because it has both male (stamens) and female (carpels) reproductive structures.
– Corn flowers are incomplete because they have separate male and female flowers on the same plant (monoecious).
– Hibiscus is a complete flower because it has both male (stamens) and female (carpels) reproductive structures.
– Corn flowers are incomplete because they have separate male and female flowers on the same plant (monoecious).