BIO153H5 Lecture Notes - Lecture 10: Polyploid, Dicotyledon, Endosperm
Document Summary
Early vascular plants: a diverse and poorly understood group. The rhynie chert: a treasure-trove for plant paleontologists (in this way, analogous to the. Burgess shale for cambrian animals, which we will see in an upcoming lecture). Chert is a silicified moor located about 40 km from aberdeen, scotland. About 400 million years ago, geysers spouted boiling hot, siliceous (silica-rich) water, preserving the plant life so perfectly that the fossils can be examined at the cellular level. 2 types of leaf structure: microphylls and megaphylls. Recall that we discussed how plant structure reflects adaptations to living on land. There are distinct competitive advantages to being taller than your neighbours if you are a plant. However, it"s hard to grow tall when you grow only via apical meristem (new cell growth only at the tips of the plant). Trees grow this way: stems thicken but do not grow outward, making the plant very unstable!
