Question

1. Angiosperms are seed-bearing plants that have flowers as reproductive structures. Angiosperms can have one of three basic life-cycle patterns: annual, biennial, or perennial.

• Annuals have a life cycle that lasts one year. A typical annual germinates during the spring, grows to maturity, and produces very colorful, showy flowers. An annual dies in fall. Its seeds lie dormant over the winter and germinate in spring to begin a new generation.
• Biennials follow a similar pattern, but over a two-year period. A biennial germinates in the spring, grows over the summer and fall, and then dies back in winter to emerge in the spring of the next year. It produces showy flowers in the summer or fall of the second year, goes to seed, and then dies. Its seeds lie dormant until spring returns.
• Perennials have a life cycle that lasts many years. Some perennials undergo cyclic changes by dying back in the winter. However, their roots do not die during this period, but remain dormant until conditions are more favorable for stem and leaf growth. Perennials generally have much less colorful, showy flowers than annuals or biennials. Their root systems are larger and more developed as well.

Biologists often talk about the need for living things to use energy to maintain their living state. Justify the claim that these angiosperm life cycles illustrate different ways that living systems have evolved to maximize the conservation of energy, yet still allow continuity of their species. (7 points)

Answer 1

Annuals are usually complete their life cycle within one year. So they show much faster growth rate than biennials and perennials. They should reach maturity within a limited period of time. Hence energy consumption and utilization are very high. They doest have time to concentrate for the most advanced, strong roots and stems due to the following strategy grow fast die fast. so roots doest grow much deeper. the stem does not become much strong because it takes much more energy. the flowers are very attractive because due to fast-growing and should reproduce much faster they attract insects and birds.

Biennials also do not give much concentration in producing advanced roots and shoot like the nature of perennials.

perennials are long-living and complete their life cycle by taking many years. So they should be live with many more adaptations. That is why most of them have a woody nature for shoots and roots. The roots extend much deeper than annuals and biennials in order to absorb nutrients and minerals .we can see they leave enough space for the growth of annuals and biennials. Perennials doest need colorful showy flowers because they are permanent plants and have enough time for reproduction and also follow many offshoot mechanisms for reproduction.

CONCLUSION

Annuals show a much faster growth rate than biennials and perennials. They have limited time to completion of life cycle hence they don't give much importance to produce much-adapted shoots and roots.

perennials give much importance for advanced root and shoot because they should live for many years. since there is enough time for complete life cycles they do not require large quantities of energy when compared to the rate of energy utilization of annuals and biennials.