BOTANY 400 - Lecture Exam 1

Phylogeny

• Pattern of Evolution

• All organisms in a taxa share a common ancestor.

• Used to find where a taxa originated.

Biosystematics

• Process of Evolution

• How, when, and where did a speciation event occur?

• Amount of Genetic Variation

Goals of Systematics

• Inventory Earth’s Biota

• Create Nomenclature for Identification & Communication

• Create an Orderly & Logical Sequence of Classification

• Demonstrate Evolutionary Implications of Biodiversity

Inventorying Earth’s Biota

• 1.9 × 10⁶ Species Discovered & Described

• Impossible to Estimate Total Number of Species

• Temperate Flora Inventory is Nearly Complete

• Tropical Flora Inventory is very open due to having many more species.

  • More endangered species as many are endemic to small areas.

• Barcode DNA to form Phylogenetic Trees

Nomenclature

• Used for Identification & Communication

  • Easier if plants have one name.

• Dichotomous Keys & Apps like iNaturalist

• Words & Vocabulary

• Important for Other Disciplines

Orderly & Logical Sequence of Classification

• Relates organisms with one another in a framework.

• Aids in Information-Retrieval as in an Herbarium or Website

• Type Species

Type Species

The species or specimen that a name is permanently attached to in the case of a taxonomic split or revision.

Demonstrating Evolutionary Implications of Biodiversity

• Detect Evolution at Work

• Understand Evolutionary Pathways

• Identify Origin of Both Ancient & Recent Diversity

• Morphological & Molecular Characteristics

• Tree of Genealogy, Phylogeny, & Life

• Looks at Processes & Patterns

The Muséum National d’Historie Naturelle

The largest herbarium in the world with approximately 8.9 million preserved plant and fungi specimens.

Algae to Angiosperms

• Largest Evolutionary Radiation of Plants

• Adaptations to Life on Land & Being Non-Motile

  • No Swimming Gametes

• Successive Rounds of Speciation & Extinction

• Set the stage for development of land-based ecosystems with fungi & animals.

• Researched through Fossils

Bryan Atkinson

• Paleobotanist & Dogwood Systematist

• Studies Fossils of Flowering Plants

  • Focused on Plants in Antarctica

• Contributed Much to Knowledge of Early Plant Evolution

Angiosperms

• Flowering Plants

• Phylum Magnoliophyta

• Majority of Plant Diversity

Fungi

• Not Plants

• Evolutionarily Closer Related to Animals

Green Algae

• Lineage Charales

• Thought to be closest relative to embryophytes.

Embryophytes

Land Plants

The First Land Plants

• First Evidence of Land Life from 460 Million Years Ago

• Microfossils of Spores

• Similar to Bryophytes like Modern-Day Liverworts

Bryophyta

• Mosses, Hornworts, & Liverworts

• Non-Vascular

• Earliest Land Plants

• Gametophyte Dominant

• 16000 Species in 3 Separate Lineages

  • Non-Taxonomic Group

Rhynia

• Extinct Vascular Plant

• Seen in Early Devonian Period

  • About 400 Million Years Ago

• One of the First Vascular Plants

• 20cm Tall with No Roots or Leaves

• Primitive Vascular Tissue

• First Known Tracheophyte

Lycopodiophyta

• Club Mosses

  • Not True Mosses

• 1150 Species in 3 Familes

• Sporophyte Dominant

• Vascular Tissue

• Free Sporing

• Microphylls

• Sister Lineage to All Other Land Plants

Polypodiophyta

• Ferns

• Immense Variation in Habit & Habitats

• Spores Stored in Sporangia

• Require more Systematic Research, especially in Tropics

• Includes Horsetails & Whisk Ferns

Horsetails

• Unusual Group of Ferns

• 15 Species in Genus Equisetum

• Vascular Plants with Reduced Leaves & Terminal Sporangia

Whisk Ferns

• Unusual Group of Ferns

• 6 Species in 2 Genera

• Leafless Vascular Plants with Green Stems & Lateral Sporangia

The First Seed Plants

• Fern-Like Plants

• Found in Late Devonian

  • About 390 to 360 Million Years Ago

• Produced Naked Seeds with Embryos in a Covering

• Formed Much of Today’s Coal

Gymnosperms

• First Found in Permian Period

  • About 286 to 245 Million Years Ago

• Big Trees with Net-Veined Leaves

• Bear Naked Seeds derived from Female Gametophyte

• Form Pollen derived from Male Gametophyte

• 870 Species in Pinophyta

• Often Divided into 4 Phyla

  • Conifers, Cycads, Gingko, & Gnetophytes

Archaefructus

• First Known Flowering Plant

• Found in Very Early Cretaceous

  • About 146 to 65 Million Years Ago

• Underdeveloped Flowers