How the Plants Colonized Land: From Algal Protists to Flowering Plants

These flashcards cover key vocabulary and concepts related to the evolution and characteristics of plants, their relationship to algae, and adaptations for life on land.

Archaeplastidia

The group that includes red algae, green algae, and land plants, which are the closest relatives of plants.

Charophytes

A group of green algae considered the closest relatives to land plants, known for their distinctive traits shared with plants.

Sporopollenin

A durable polymer produced by charophytes that prevents exposed zygotes from drying out and is a major component of spore and pollen walls in many plants.

Alternation of Generations

The life cycle of plants that includes both a multicellular haploid gametophyte and a multicellular diploid sporophyte.

Gamete

A haploid reproductive cell that can fuse with another gamete to form a diploid zygote.

Apical Meristems

Localized regions of cell division in plants that allow for continuous growth and differentiation into various tissues.

Multicellular Gametangia

Structures within which gametes are produced; female gametangia, or archegonia, produce eggs, while male gametangia, or antheridia, produce sperm.

Vascular Tissue

Specialized tissue in plants that includes xylem and phloem for the transport of water, nutrients, and organic compounds.

Microphylls

Leaves characterized by a single vein that evolved from stem outgrowths, first appearing in the fossil record around 410 mya.

Megaphylls

Leaves with highly branched vascular systems that are thought to have evolved from webbing between flattened branches, appearing in the fossil record around 370 mya.

Homosporous

A term describing plants that produce one type of spore that can develop into a bisexual gametophyte.

Heterosporous

Referring to plants that produce two distinct types of spores; megaspores develop into female gametophytes and microspores develop into male gametophytes.

Xylem

Vascular tissue responsible for conducting water and minerals from the roots to the rest of the plant.

Phloem

Vascular tissue responsible for distributing organic nutrients produced by photosynthesis throughout the plant.

Cuticle

A waxy, protective layer found on the epidermis of most land plants, preventing water loss.

Stomata

Pores on the surface of leaves and stems that regulate gas exchange (CO\text{CO}2 intake and O\text{O}2 release) and water vapor transpiration.

Rhizoids

Root-like structures that anchor non-vascular plants (like mosses) to a substrate, but do not absorb water and nutrients like true roots.

Embryophytes

The formal term for land plants, characterized by the presence of an embryo protected by parental tissue.

Gametophyte

The multicellular haploid (n) stage in the plant life cycle that produces gametes by mitosis.

Sporophyte

The multicellular diploid (2n) stage in the plant life cycle that produces spores by meiosis.

Sporangia

Structures on the sporophyte where spores are produced.

Archegonium

The female gametangium in plants that produces a single nonmotile egg and protects the developing embryo.

Antheridium

The male gametangium in plants that produces and releases sperm.

Bryophytes

Non-vascular plants, including mosses, liverworts, and hornworts, characterized by a dominant gametophyte stage and dependence on water for reproduction.

Seedless Vascular Plants

Plants that possess xylem and phloem for transport but reproduce via spores, such as ferns and horsetails.

Tracheophytes

A scientific name for vascular plants, characterized by the presence of xylem and phloem for water and nutrient transport.

Lignin

A complex polymer embedded in the cellulose matrix of plant cell walls, especially abundant in xylem, providing structural support and allowing plants to grow tall.

Sporophyll

Modified leaves that bear sporangia, observed in both seedless vascular plants and seed plants.

Sori

Clusters of sporangia, typically found on the undersides of fern leaves (megaphylls).

Gametophore

A mature, gamete-producing structure found in some bryophytes, which develops from the protonema.

Protonema

A thread-like chain of cells that forms the initial stage of a bryophyte (moss or liverwort) gametophyte, typically developing from a spore.

True Roots

Multi-celled organs in vascular plants that anchor the plant and absorb water and dissolved nutrients from the soil.

True Stems

Axial organs in vascular plants that provide structural support, elevate leaves and reproductive structures, and contain vascular tissues for transport.

Lycophytes

A group of seedless vascular plants, including club mosses, spike mosses, and quillworts, characterized by microphylls.

Monilophytes

A diverse group of seedless vascular plants that includes ferns, horsetails, and whisk ferns, characterized by megaphylls (except whisk ferns).