EEMB 3 - plants

Adaptation

Heritable characteristic that increases fitness in a particular environment.

Archaeplastida

Major eukaryotic lineage including green plants, red algae, and glaucophytes that contain chloroplast.

Autotroph

Organism that uses inorganic carbon, typically CO₂, to produce organic compounds.

Carbon fixation

Incorporation of inorganic carbon into organic compounds.

Chloroplast

Organelle where photosynthesis occurs in plants and many algae.

Common ancestor

An ancestral organism or population from which two or more lineages descended.

Heterotroph

Organism that obtains carbon from organic compounds.

Lithotroph

An organism that uses inorganic substances (such as water, hydrogen gas, or ammonia) as a source of electrons for its metabolism.

Mycoheterotrophy

Nutritional strategy in which a plant obtains organic carbon through associated fungi.

Parasitic plant

Plant that obtains resources from another living plant.

Photosynthesis

Process that uses light energy to drive chemical reactions, including carbon fixation in oxygenic photosynthesis.

Phototroph

Organism that uses light for energy.

Primary producer

Organism that produces organic matter from inorganic carbon, providing a foundation for food webs.

Phylogeny

Evolutionary history and relationships among organisms.

Brown algae

A group of mostly marine, photosynthetic eukaryotes that includes kelp. Their chloroplasts originated through secondary endosymbiosis.

Chloroplast

An organelle in plants and algae where photosynthesis occurs, converting light energy into chemical energy.

Chlorophyll

A green pigment found in chloroplasts that absorbs light energy, primarily at red and blue wavelengths, to drive photosynthesis.

Endosymbiosis

A relationship in which one organism lives inside another. Over evolutionary time, an engulfed organism may become an organelle, such as a chloroplast.

Green algae

A diverse group of photosynthetic eukaryotes containing chlorophyll a and b. They include the closest relatives of land plants.

light absorption

The process by which a pigment takes in light energy at particular wavelengths.

light reflection

The process by which light bounces off a surface rather than being absorbed, contributing to the color we see.

Red algae (Rhodophyta)

A group of mostly marine, photosynthetic eukaryotes with accessory pigments that absorb blue-green light, allowing many species to photosynthesize in deeper water.

wavelength

The distance between successive peaks of a light wave. Different wavelengths correspond to different colors of visible light.

Streptophyta

The evolutionary lineage containing charophyte algae and land plants.

Charophytes

Green algae that are more closely related to land plants than chlorophytes are.

Embryophytes

Land plants, characterized by multicellular embryos retained and nourished by the parent.

Derived trait

An evolutionary characteristic that arose in a lineage relative to its ancestors.

Photosynthetic pigment

A molecule that absorbs particular wavelengths of light used in photosynthesis.

Mitosis

Cell division that maintains chromosome-set number in the daughter cells.

Meiosis

Cell division that reduces chromosome-set number from diploid to haploid.

Fertilization

Fusion of haploid gametes to produce a diploid zygote.

Gamete

A haploid reproductive cell that fuses with another gamete during fertilization.

Spore

A haploid cell that can develop into a new organism without fusing with another cell.

Zygote

The diploid cell formed by fertilization.

Gametophyte

The multicellular haploid generation that produces gametes by mitosis.

Sporophyte

The multicellular diploid generation that produces haploid spores through meiosis.

Alternation of generations

A life cycle alternating between multicellular haploid gametophytes and multicellular diploid sporophytes.

Sporangium

A structure in which spores are produced.

Antheridium

A reproductive structure that produces sperm in many non-seed plants.

Archegonium

A reproductive structure that produces and contains an egg in many land plants.

Rhizoid

A root-like structure that helps anchor nonvascular plants to a surface.

Sporopollenin

A highly resistant substance in spore and pollen walls that helps protect them from drying out and environmental damage.

Cuticle

A waxy, protective layer covering plant surfaces that reduces water loss.

Apical meristem

A region of actively dividing cells at the tip of a plant shoot or root that allows growth in length.

Mycorrhiza

A symbiotic association between a fungus and a plant, typically involving the exchange of nutrients and carbon.

Arbuscular mycorrhiza (AM)

A type of plant–fungus association in which fungal structures called arbuscules form inside plant cells and facilitate nutrient exchange.

Bryophytes (sensu lato)

A group comprising liverworts, mosses, and hornworts; nonvascular land plants with dominant gametophytes.

Liverworts (Hepatophyta)

Nonvascular land plants that often have flattened, leaf-like or thalloid gametophytes.

Mosses (Bryophyta)

Nonvascular plants with dominant gametophytes, often consisting of leafy shoots.

Hornworts (Anthocerophyta)

Nonvascular plants characterized by elongated, horn-like sporophytes.

Gemmae

Asexual reproductive structures that can develop into new individuals without fertilization.

Gemma cup

A cup-like structure found in some liverworts that produces and disperses gemmae.

Stomata

Epidermal pores surrounded by guard cells, specialized cells that control the opening and closing of stomata to regulate gas exchange.

Biological weathering

The breakdown or chemical alteration of rocks through the activities of organisms.

Nitrogen fixation

Conversion of atmospheric N₂ into biologically available nitrogen compounds by certain microorganisms.

Peat bog

A waterlogged, often acidic wetland in which partially decomposed plant material accumulates as peat.

Peat

Accumulated, partially decomposed organic matter formed in waterlogged environments.

Sphagnum

A genus of mosses important in peat formation and water retention.

Anaerobic

Describing conditions in which molecular oxygen is absent.

Carbon sequestration

The capture and long-term storage of carbon, preventing its rapid return to the atmosphere as CO₂.

Tracheophytes

Vascular plants characterized by specialized xylem and phloem tissues.

Independent sporophyte

A diploid plant generation capable of growing and obtaining resources independently of the gametophyte.

Sporophyll

A modified leaf that bears one or more sporangia.

Sorus (plural: sori)

A cluster of sporangia, commonly found on fern fronds.

Sporangium (plural: sporangia)

A structure in which spores are produced.

Dichotomous branching

A branching pattern in which a growing axis divides into two branches.

Vascular tissue

Specialized plant tissues responsible for long-distance transport of water, minerals, and sugars.

Independent sporophyte

A sporophyte that can survive and grow without depending nutritionally on its gametophyte

Xylem

Vascular tissue that transports water and dissolved minerals; its water-conducting cells are dead at maturity and have lignified walls.

Phloem

Vascular tissue that transports sugars and other organic compounds between plant tissues.

Lignin

A complex phenolic polymer that strengthens cell walls, increases their resistance to compression, and makes them more hydrophobic.

Aglaophyton

An extinct early land plant with branching sporophytes and rhizoids, illustrating an intermediate stage in early land plant evolution.

Homospory

Production of one type of spore, typically developing into a gametophyte capable of producing both sperm and eggs.

Heterospory

Production of two distinct types of spores: microspores and megaspores.

Microspore

A smaller haploid spore that develops into a male gametophyte.

Megaspore

A larger haploid spore that develops into a female gametophyte.

Microgametophyte

A male haploid gametophyte that produces sperm.

Megagametophyte

A female haploid gametophyte that produces eggs.

Bisexual gametophyte

A gametophyte that produces both eggs and sperms.

Strobilus

A reproductive structure consisting of a cluster of sporophylls, often forming a cone-like structure.

Annulus

A specialized ring or row of cells in a fern sporangium that helps release spores through changes in water pressure.

Elaters

Hygroscopic structures associated with spores that respond to humidity changes and assist in spore dispersal.

Seed plant

A vascular plant that reproduces using seeds; includes gymnosperms and angiosperms.

Monophyletic group (clade)

A group consisting of a common ancestor and all of its descendants.

Heterospory

Production of two types of spores: microspores that develop into male gametophytes and megaspores that develop into female gametophytes.

Microspore

A haploid spore that develops through mitosis into a male gametophyte.

Megaspore

A haploid spore that develops through mitosis into a female gametophyte.

Reduced gametophyte

A gametophyte consisting of relatively few cells and dependent on the sporophyte for protection and/or nutrition.

Pollen grain

A structure containing the reduced male gametophyte of a seed plant, which develops from a microspore.

Ovule

A reproductive structure containing the megasporangium, surrounded by an integument, that develops into a seed after fertilization.

Seed

A reproductive structure containing a plant embryo, stored nutrients, and a protective seed coat.

Sporopollenin

A highly resistant polymer found in pollen and spore walls that helps protect against desiccation and degradation.

Microstrobilus (pollen cone)

A reproductive cone containing microsporangia that produce microspores.

Megastrobilus (ovulate cone)

A reproductive cone bearing ovules in which megaspores and female gametophytes develop.

Integument

Diploid maternal sporophyte tissue surrounding the megasporangium that develops into the seed coat.

Gymnosperm

A seed plant whose seeds are not enclosed within an ovary or fruit.

Coniferophyta

The largest living gymnosperm lineage, including pines, firs, spruces, and redwoods.

Cycadophyta

A gymnosperm lineage characterized by large compound leaves and generally separate male and female plants.

Ginkgophyta

A gymnosperm lineage represented today by a single living species, Ginkgo biloba.

Gnetophyta

A gymnosperm lineage containing the three living genera Gnetum, Ephedra, and Welwitschia.