8. Angiosperms originated during
(1) Upper cretaceous                                                (2) mid cretaceous
(3) Late cretaceous                                         (4) Carboniferous

Introduction

Angiosperms, or flowering plants, are the most diverse and ecologically dominant group of land plants today. Their origin marks a major evolutionary milestone, transforming terrestrial ecosystems and supporting the rapid diversification of insects and other animal groups. But when did angiosperms first appear in Earth’s history?

Fossil and Molecular Evidence for Angiosperm Origin

• Fossil Record: The oldest undisputed angiosperm fossils, including pollen and leaf impressions, date to the early Cretaceous period, about 125–135 million years ago1356. While there are rare, earlier traces attributed to angiosperms, the fossil record becomes clear and abundant only in the Cretaceous.

• Diversification: By the mid to late Cretaceous, angiosperms had rapidly diversified and become widespread, with many modern groups appearing in the fossil record356.

• Dominance: Although angiosperms originated in the early Cretaceous, they became ecologically dominant later in the Cretaceous, eventually surpassing gymnosperms and ferns as the primary vegetation16.

Why Not Earlier Periods?

• Jurassic and Carboniferous: While some molecular data suggest possible earlier origins, there is no reliable fossil evidence of angiosperms from the Jurassic or Carboniferous periods236.

• Cretaceous as the Key Period: The consensus among paleobotanists is that angiosperms originated and began to diversify during the Cretaceous, with the earliest fossils dating back to the lower (early) Cretaceous136.

The Correct Answer

Given the options:

1. Upper Cretaceous

2. Mid Cretaceous

3. Late Cretaceous

4. Carboniferous

The correct answer is:
(2) Mid Cretaceous

• While the very first angiosperms appeared in the early Cretaceous, the massive appearance, rapid diversification, and ecological dominance of angiosperms occurred by the mid Cretaceous356. This is when flowering plants became a major component of terrestrial ecosystems.

Conclusion

Angiosperms originated during the Cretaceous period, with the earliest fossils dating to the early Cretaceous and their explosive diversification and dominance occurring by the mid Cretaceous. This evolutionary leap paved the way for the modern landscapes we see today, filled with a rich variety of flowering plants.