Announcements

Finish up your data collection and organization for the Urban Forestry project.

I will be posting more reading Thursday.

I will try and get your writing assignments back to you on Thursday.

Plant diversity

Continuing with Chapter 7 and into Chapter 8.

Early evolution of seed plants.

Ordovician and Silurian are the periods with evidence for the earliest land plants.

Carboniferous was a period of vast 'silent' forests of lycophytes.

Early seed plants through the Mesozoic.

Most evidence had suggested previously that flowering plants had evolved towards the end of the Cretaceous.

More recent findings suggest flowering plants probably go back in time to the Jurassic.

Figure 7.5 Morphology of basal embryophytes

Figure 7.6 Phylogenetic relationships at base of embryophytes

Figure 7.8 Phylogeny of tracheophytes (vascular plants)

Figure 7.11 Archaeopteris and early seed plants

Archaefructis – new flowering plant discovered in China recently. Dates from early Cretaceous.

Lobospermum – charcoalified seeds and flowers from early Cretaceous and even into the Jurassic.

Evolution of plant diversity

The difficulty of placing fossils on phylogenetic trees.

How do you know the fossil is actually on the 'stem'?

The fossil simply indicates the latest possible date or minimum estimate of the age of a group.

Gymnosperms (Fig. 7.12)

Cycadales – cycads

Gingkoales – 1 family, 1 species – Gingko biloba

Coniferales – five families

Gnetales – 3 very distinct families

Figure 8.20 Cycadaceae. Cycas circinalis

Swimming sperm

Figure 8.21 Zamiaceae. Zamia floridana

Figure 8.22 Ginkgoaceae. Broad leaf of Ginkgo biloba

Figure 8.23 Relationships among major groups of conifers, with potential synapomorphies for the 5 families covered.

Figure 8.24 Pinaceae. Pinus subgen. Strobus, P. strobus

Figure 8.25 Cupressaceae

Figure 8.26 Araucariaceae

Figure 8.27 Taxaceae. Taxus floridana

Figure 8.28 Ephedraceae. Ephedra distachya

Welwitschia