Gymnosperms: Naked Seeds, Cones and Life Cycle
The gymnosperms take their name from two Greek words — gymnos (naked) and sperma (seed) — because their ovules are never sealed inside an ovary wall. This quiz tests the whole lesson: the exposed ovule, the mycorrhizal roots of Pinus, the coralloid roots of Cycas, the male and female strobili, the reduced pollen grain, and the fertilisation that turns an ovule into an uncovered seed.
What you will practise
- The precise meaning of “naked seed” and how it differs from an enclosed ovary.
- Root, stem and leaf adaptations — mycorrhiza, coralloid roots, needle leaves, thick cuticle, sunken stomata.
- Microsporophylls and megasporophylls, male and female cones, and their arrangement on Pinus and Cycas.
- The non-free-living gametophytes and the path from pollen grain to seed.
Work carefully: several options are true statements placed in the wrong context. Read each question to the end before choosing.
Q1. The name "gymnosperm" is derived from two Greek words. What do they mean?
The lesson states gymnos means naked and sperma means seed, so the name records the exposed condition of the seeds.
Q2. In gymnosperms, the ovules remain exposed:
The ovules are not enclosed by any ovary wall and remain exposed both before and after fertilisation.
Q3. Which statement best explains why gymnosperm seeds are described as "naked"?
The integument is present; what is absent is the enclosing ovary wall, so the resulting seeds are not covered.
Q4. Which of the following is described in the lesson as one of the tallest tree species?
The giant redwood tree Sequoia is named as one of the tallest tree species.
Q5. The roots of gymnosperms are generally:
The lesson states that the roots are generally tap roots; coralloid roots occur only in some genera such as Cycas.
Q6. In Pinus, the roots have a fungal association known as:
Roots in some genera have fungal association in the form of mycorrhiza, and Pinus is the example given.
Q7. The small specialised roots of Cycas are called coralloid roots because they are associated with:
Coralloid roots of Cycas are associated with ##\ce{N2} - fixing## cyanobacteria.
Q8. Which pairing of stem habit with genus is correct according to the lesson?
The stems are unbranched in Cycas and branched in Pinus and Cedrus.
Q9. The pinnate leaves of Cycas are described as persisting for:
In Cycas the pinnate leaves persist for a few years.
Q10. Which set of features helps conifer leaves reduce water loss?
In conifers the needle-like leaves reduce surface area, and the thick cuticle and sunken stomata further reduce water loss.
Q11. The leaves of gymnosperms are well adapted to withstand:
The lesson states the leaves are well-adapted to withstand extremes of temperature, humidity and wind.
Q12. Sporophylls bearing sporangia are arranged spirally along an axis to form:
The two kinds of spores are produced in sporangia borne on sporophylls arranged spirally along an axis to form lax or compact strobili or cones.
Q13. The strobili that bear microsporophylls and microsporangia are called:
Strobili bearing microsporophylls and microsporangia are the microsporangiate or male strobili.
Q14. The reduced male gametophyte of gymnosperms, confined to a limited number of cells, is called the:
The microspores develop into a highly reduced male gametophyte confined to a limited number of cells, and this reduced gametophyte is called a pollen grain.
Q15. Where does the development of pollen grains take place?
The lesson states that the development of pollen grains takes place within the microsporangia.
Q16. In Cycas, how are the male cones and megasporophylls distributed?
In Cycas male cones and megasporophylls are borne on different trees, whereas in Pinus both may be borne on the same tree.
Q17. The megaspore mother cell is differentiated from one of the cells of the:
The megaspore mother cell is differentiated from one of the cells of the nucellus, which is protected by envelopes to form the ovule.
Q18. After meiosis, how many megaspores are formed, and how many develop into the female gametophyte?
The megaspore mother cell divides meiotically to form four megaspores, and one of them develops into the multicellular female gametophyte.
Q19. Which statement about the gametophytes of gymnosperms is correct?
Unlike bryophytes and pteridophytes, in gymnosperms the male and female gametophytes do not have an independent free-living existence and remain within the sporangia retained on the sporophytes.
Q20. Following fertilisation in gymnosperms, the zygote develops into an embryo and the ovules develop into:
Following fertilisation the zygote develops into an embryo and the ovules into seeds, and these seeds are not covered.