Botany | Plant Systematics and Life Cycles | Dr. Sara Browning | PBA Fall 2024

Systematics

study of the diversity of life and the evolutionary relationships between organisms

Phylogenetic

pertaining to the development of a species

Taxonomy

The scientific study of how living things are classified

Biodiversity

the variety of life in the world or in a particular habitat or ecosystem.

Herbalists

Wrote Herbals- books of medicinal plants

(1400-1700's)

Herbals

Books of medicinal plants

Linnaeus

- mid 1700's

Wrote the first real flora-species Plantarum 1753

Introduced binomial system of nomenclature

Introduced a new rank-based taxonomic system

binomial system of nomenclature

System of naming a species by the combination of the genus name and a specific epithet.

Kingdom, Phylum, Class, Order, Family, Genus, Species

taxonomic order

Linnaeus

Named: 7700 species of plants

4400 species of animals, including Homo sapiens

Philosophia Bontanica

Contains the rules of naming:

- "Every plant name must consist of a generic name and a specific one."

- Names should be sensible, only by botanist

- "Generic names one and a half feet long, those that are difficult to pronounce, or are disgusting, should be avoided"

Linnaeus

Father of taxonomy

Darwin

- mid 1800's

"On the Origin of Species" 1859

Birth of systematics

Natural taxonomy

From Darwin into the 1900's

Goal became ______ ______; reflects common ancestry; uses homologous characteristics

Replaced artificial taxonomy and analogous characteristics

Artificial

Natural or artificial? "Taxonomic group for all plants that produce tubers"

Natural

Natural or artificial? "Phylum for plants producing flowers and fruits (angiosperms)"

Natural

Natural or artificial? "Taxonomic class for plants with single cotyledon (monocots)"

Artificial

Natural or artificial?

"Taxonomic family for all carnivorous plants"

Artificial

Natural or artificial?

"Phylum or class for all woody plants"

Natural

Natural or artificial?

"Phylum for plants producing sieve tube members (angiosperms)"

Artificial

Natural or artificial?

"Group for all angiosperms with purple flowers"

Natural

Natural or artificial?

"Family for all plants with a composite flower (sunflower family)"

Classical

Current Taxonomy

- Opinions of professional taxonomists

Cladistics

Current Taxonomy

- Computerized, specific design to eliminate bias

Based entirely on common ancestry

Phylogenetically important characteristics only

Primitive traits

Current Taxonomy

ID ancestral =

advanced traits

Current Taxonomy

ID derived =

clades

Current Taxonomy

Organisms grouped into _____

Clade

Current Taxonomy

______ = common ancestor and all descendants

Displayed as a cladogram

cladogram

Diagram that shows the evolutionary relationships among a group of organisms

cladogram of plants

Node

_____ is a branch point and represents a common ancestral population

Sister groups

- share a common ancestor

Synapomorphy

- derived trait shared by a clade

Monophyletic group

Common ancestor and all descendants

Paraphyletic group

All descendants not included

Polyphyletic group

More than one common ancestor

Kingdom Protista

Contain one celled eukaryotes such as algae and protozoa.

Eukaryote supergroups

- Alveolata

- Stramenopila

- Rhizaria

- Excavata

- Opisthokonta

- Amoebozoa

- Plants and algal relatives

PhyloCode

International Code of Phylogenic Nomenclature

Barcoding

- rapid ID of a plant Theory- plastid DNA may be unique for any species

- Nucleotide sequence produced (several possibilities exist)

- Database established for comparison

- Very successful for animals

Sporophyte

Diploid, or spore-producing, phase of an organism

Gametophyte

The stage in the life cycle of a plant in which the plant produces gametes, or sex cells.