Introduction to Botany - Lecture 1 Flashcards

Vocabulary flashcards created from Lecture 1 covering plant features, Earth's early history, photosynthesis impact, adaptations to terrestrial life, vascular tissues, taxonomy, systematics, and cladistics.

Plant

A multicellular, photosynthetic autotroph with cell walls made of cellulose, membrane-bound organelles, roots, leaves, and specialized tissues for support and conduction that stores energy as starch.

Autotrophs

Organisms that make their own energy, which evolved 3.4 billion years ago and introduced a direct flow of sunlight energy into the biosphere.

Stromatolites

The earliest fossils on record, dating to 3.4 billion years ago.

Banded Iron Formations

Rock formations formed when $O_2$ gas produced by early photosynthetic organisms reacted with iron in the ocean.

Great Oxidation Event

The period 2.7 to 2.2 billion years ago during which $O_2$ gas accumulated in Earth's atmosphere.

Anoxic atmosphere

Earth's early atmosphere prior to photosynthesis, characterized by essentially zero free oxygen gas and dominated by $H_2$, $CH_3$, $NH_3$, and rich in $CO_2$.

Arctacellularia tetragonala

A ~1 billion-year-old fossil algae species described by Sforna et al. (2022) representing early multicellular photosynthetic eukaryotes.

Embryophytes

Plants characterized by the retention of a developing multicellular diploid embryo within an archegonium or female gametophyte.

Sporopollenin

A chemical component of haploid spore walls that resists decay and drying to protect spores in terrestrial reproduction.

Imbibition

The absorption of water by a seed that, along with other external cues, is required to break dormancy.

Stomata

Pores in the epidermis of leaves that open for gas exchange and transpiration and close to prevent water loss.

Xylem

Highly specialized vascular tissue that transports water and minerals from the roots to the upper portions of the plant (stem, branches, leaves).

Phloem

Highly specialized vascular tissue that transports sugars, hormones, and secondary metabolites throughout the plant based on electrochemical gradients.

Taxonomy

The system of classifying and naming organisms based on observable characteristics, established by Carolus Linnaeus.

Systema Naturae

The work by Carolus Linnaeus whose 10th edition (published in 1758) described ~4,400 species of animals and ~7,700 species of plants.

Georges-Louis Leclerc, Comte de Buffon

A natural historian critical of Linnaeus's rigidity, now considered a precursor to Darwin and other natural historians.

Systematics

The method by which scientists reconstruct evolutionary relationships between organisms based on similarities in DNA.

Clade

A branch on the tree of life consisting of its originating taxon and all descendant taxa.

Node

The point on a cladogram where two branches diverge, representing a speciation event.

Root

The oldest node of a cladogram.

Monophyletic group

A phylogenetic group that includes an ancestor and all of that ancestor's known descendants.

Polyphyletic group

A phylogenetic group that includes descendants from multiple branches but does not include their most recent common ancestor.

Paraphyletic group

A phylogenetic group that includes an ancestor and some, but not all, of its descendants.