Chapter 30.2, Problem 3CC

Summary Introduction

To draw: A phylogenetic tree of seed plants depicting the relationship between Elkinsia, gymnosperms, and the angiosperms.

Concept introduction: The first evidence of seed plant comes from 360 million-year-old fossils of plants in the genus Elkinsia. Elkinsia is a group of extinct gymnosperms. It lived 55 million years before the first fossil was classified as gymnosperms.

The early seed plants became extinct, and there is no information about the lineage that gave rise to the gymnosperms. The early gymnosperms lived in the Carboniferous Period. In the Permian period, the gymnosperms replaced the lycophytes and ferns. In the late Mesozoic era, the angiosperms started to replace the gymnosperms.