BIO 102 Lecture Notes: Plant Kingdom Characteristics & Classification

Vocabulary flashcards covering the characteristics, classification groups (Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms), ecological adaptations, and life processes of the Plant Kingdom.

Whittaker Kingdom Classification

A five-kingdom classification system proposed by Robert Whittaker in 1969, dividing living organisms into Kingdom Monera, Kingdom Protist, Kingdom Fungi, Kingdom Plantae, and Animal Kingdom.

Alternation of Generations

A reproductive cycle in the Plant kingdom involving both a haploid gametophyte phase and a diploid sporophyte phase.

Cryptogams

A group of seedless, non-flowering plants that reproduce via spores; it includes the phyla Thallophyta, Bryophyta, and Pteridophyta.

Phanerogams

Also known as spermatophytes, these are seed-bearing plants divided into two major groups: Gymnosperms and Angiosperms.

Thallophyta

A subclass of plants, commonly known as algae, characterized by a thallus (simple plant body), living in moist environments, and lacking true roots or vascular tissue.

Lichen

A symbiotic association between fungi and algae (or cyanobacteria) where the algae produce food and the fungi provide a protected environment.

Bryophytes

Known as the "amphibians" of the plant kingdom, these are non-vascular plants including mosses, liverworts, and hornworts that lack true roots, stems, and leaves.

Rhizoids

Root-like structures in bryophytes that assist in clinging to surfaces but do not absorb nutrition.

Pteridophytes

The first true terrestrial plants, which possess vascular tissue (xylem and phloem) but are seedless (vascular cryptogams) and reproduce via spores.

Circinate Vernation

A characteristic of young pteridophyte leaves where the tips curl inward to protect vulnerable growing regions from predators.

Gymnosperms

Plants with "naked" seeds that are not enclosed in a fruit; examples include conifers such as $Pinus$ and $Cycas$.

Coralloid Roots

Specialized roots found in $Cycas$ that are associated with nitrogen-fixing cyanobacteria.

Mycorrhiza

A symbiotic association between fungi and the taproot system of certain gymnosperms, such as $Pinus$.

Angiosperms

A diverse group of flowering plants whose seeds are enclosed within a protective structure called fruit.

Monocotyledons (Monocots)

Angiosperms characterized by seeds with one cotyledon, adventitious roots, and trimerous flowers.

Dicotyledons (Dicots)

Angiosperms characterized by seeds with two cotyledons, taproots, and reticulate leaf venation.

Transpiration

The loss of $H_2O$ in the form of vapor from the leaves of a plant, which aids in mineral absorption and temperature regulation.

Translocation

The movement of soluble products of photosynthesis through the vascular tissue called phloem.

Hydrophytes

Plants adapted to live in water or wetlands, such as $Eichhornia$ (free-floating) and $Hydrilla$ (rooted submerged).

Xerophytes

Plants adapted to dry or desert conditions, which may be succulents (drought-tolerant), non-succulents (drought-resistant), or ephemerals (drought-escapers).

Pneumatophores

Also called respiratory roots, these are negatively geotropic roots with pneumathodes used for ventilation in halophytes (mangroves).

Vivipary

A mode of seed germination found in halophytes where the seed germinates while still attached to the parent plant.

Apical Meristems

Zones of cell division responsible for axial growth (increase in height) of the plant in both the shoot and root regions.

Lateral Meristems

Tissues responsible for the lateral growth or increase in the girth of woody plants, producing secondary tissue.

Differentiation

The process by which undifferentiated cells transform into specialized cells with distinct morphological and physiological characteristics.

Dedifferentiation

The process where mature, differentiated cells revert to an undifferentiated state to divide again, often observed during tissue damage.

Sigmoid Curve

An S-shaped graph representing the "grand period of growth," which includes the lag phase, log (exponential) phase, and stationary phase.

Exponential Growth Formula

Expressed as $W_1 = W_0 e^{rt}$, where $W_1$ is final size, $W_0$ is initial size, $r$ is growth rate (efficiency index), and $t$ is time.

Thermo-periodicity

The effect of the alternation of temperature between day and night on plant growth.

Sun Plants

Plants that make vigorous growth and flower profusely when exposed to full sunlight intensities.

$C/N$ Ratio

The ratio of carbohydrates to nitrogenous compounds that governs plant growth patterns; a higher ratio favors vegetative growth, flowering, and fruiting.