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TERMGROUPDEFINITION
SACCATEADJPLANTSPronunciation:

Etymology:

In the form of a sac.
SAMARANPLANTSPronunciation:

Etymology:

A dry indehiscent winged fruit.
SARCINOIDADJPLANTSPronunciation:

Etymology:

A kind of thallus made of three-dimensional clusters of cells.
SCALARIFORMADJPLANTSPronunciation:

Etymology:

Ladder-like or having ladder-like markings.
SCALENANIMALS, PLANTS, PROTISTSPronunciation:

Etymology:

Protist scales are regular overlapping structures on the outside of the cell. They may be organic, silicaceous, or carbonaceous and may serve as an articulated cell wall. Scales may occur on the cells of a range of unrelated taxa.
SCHIZOCARPNPLANTSPronunciation:

Etymology:

A fruit derived from a syncarpous ovary which breaks up at maturity into 1-seeded portions (mericarps).
SCHIZOCOELICADJANIMALSClick here
SCHIZOGONYNPROTISTSPronunciation:

Etymology:

Schizogony is the multiple cytokinesis of a plasmodial (multinucleate) cell to form a population of uninucleate cells. This is a typical type of cytokinesis in apicomplexans, microsporans, and myxozoans. Schizonony that produces merozoites (the infective form) is called merogony.
SCLEROTIUM (SCLEROTIA)NPROTISTSPronunciation:

Etymology:

A sclerotium (sclerotia) is a portion of a Myxotist plasmodium that forms a hardened chitinous outer covering as protection against dessication or other environmental extremes. Thus, it is an asexual structure that, while multinucleate, behaves as a cyst.
SCOLEX (SCOLECES)NANIMALSPronunciation:

Etymology:

A scolex is the anterior or attachment structure of a tapeworm.
SECONDARY ZOOSPORENPPROTISTSPronunciation:

Etymology:

These zoospores are formed upon germination of the primary zoospores. Flagella emerge from the lateral groove.
SECONDARY VASCULAR TISSUENPPLANTSPronunciation:

Etymology:

Secondary vascular tissue develops from a cambium.
SEEDNPLANTSPronunciation:

Etymology:

Unit of sexual reproduction in some plants. Formed when an ovule is fertilized and comprised of outer coat that encloses stored food and an embryo.
SELECTIONNEVOLUTIONPronunciation & Etymology: Selection is a common word in English.

Selection (n.) is the non-random survival or reproduction of living things. The term, selection, in a Biological sense was applied to what animal and plant breeders do (artificial selection) before Darwin applied it to the action of nature in the production of new species (natural selection).

Types of selection include:
– artificial selection
– natural selection
– kin selection
– sexual selection
– stabilizing selection
– group selection
SEPALNPLANTSPronunciation:

Etymology:

Single segments of the calyx.
SEPTATEADJANIMALS, PLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

Septate means walled or partitioned.
SEPTUM (SEPTA)NPLANTS, PROTISTS, FUNGI, BACTERIAPronunciation:

Etymology:

A septum (septa, pl.) is a crosswall. It can be the crosswall in a filament, or the mesentary in a cnidarian.
SESSILEADJECOLOGYPronunciation:

Etymology:

Sessile is sedentary or attached to a substrate.
SETA (SETAE)NANIMALS, PLANTSPronunciation:

Etymology:

The stalk of the sporophyte capsule.
SEXUAL SELECTIONNPEVOLUTIONPronunciation & Etymology: The phrase comes from two common English words. Selection has been defined elsewhere.

Sexual selection is a type of selection that operates on traits related to mating. Defined by Darwin in the Descent of Man, sexual selection may be so strong that it may act counter to natural selection. For example, the extreme features of certain birds and mammals certainly are consequences of sexual selection. The tail of the peacock may be attractive to the female, but the mating display also makes the male more visible to predators and makes flight less efficient.
SIEVE TUBENPPLANTSPronunciation:

Etymology:

Sieve tubes are the phloem elements through which dissolved food molecules move.
SILICANPLANTS, PROTISTSPronunciation:

Etymology:

Silica is silicon dioxide (SiO2).
SIPHONNANIMALSPronunciation:

Etymology:

A siphon is a funnel-shaped tube that connects the mantle cavity to the outside in marine mollusks.
SIPHONOSTELENPLANTSPronunciation:

Etymology:

A siphonostele is a type of stele that has a parenchymatous pith in the center of continuous rings of vascular tissue.
SIPHONOUSADJPLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

Siphonous (adj) describes a filament that has no cross walls.
SIPHUNCLENANIMALSPronunciation:

Etymology:

The siphuncle is a thin strand of living tissue in nautiloids that connects the animal’s body to the chambers of the shell.
SOLENOSTELENPLANTSPronunciation:

Etymology:

See amphiphloic siphonostele.
SOLFATARANECOLOGYPronunciation:

Etymology:

Solfatara are environments that have elevated temperatures and are rich in sulfur compounds. Examples are deep ocean vents and hot volcanic springs.
SOREDIUM (SOREDIA)NFUNGIPronunciation:

Etymology:

Round or scale-like body on thallus of some lichens, which contains alga and fungal hyphae, by which lichen is propogated.
SORUS (SORI)NPLANTS, PROTISTSPronunciation:

Etymology:

A sorus is a fertile region (sporangium-bearing region) on a leaf.
SPADIX (SPADICES)NPLANTPronunciation:

Etymology:

A spike with a fleshy axis, usually subtended by a special showy bract called a spathe.
SPATULATEADJPLANTPronunciation:

Etymology:

Adjective defining leaves with a broad rounded apex and a narrow base.
SPECIATIONNEVOLUTIONPronunciation: spe-se-A-shun

Etymology: It is derived from species with the suffix -ation, which means the act of.

Speciation is the formation of new species, which comes from changes in related organisms to the point where they are different enough to be considered separate species (no longer capable of interbreeding).

In theory, speciation can occur in three different ways:
– Allopatric speciation
– Peripatric speciation
– Sympatric speciation
SPECIES (THIS WORD IS BOTH SINGULAR AND PLURAL; THERE IS NO PARTICULAR PLURAL FORM)NSYSTEMATICSPronunciation: SPE-shes; the word is both singular and plural. That is, it is ALWAYS PRONOUNCED with the terminal s.

Etymology: Species is a Latin word that means appearance or kind (as in type of).

Species, a noun that is both singular and plural refers to the fundamental unit of evolutionary biology. Species concepts differ according to the group in question.

In animals, plants, and other sexual eukaryotes, the Biological Species Concept (BSC) is the dominant theoretical means for defining a species. According to the BSC, species are natural populations that can breed and produce fertile offspring. This definition works for sexual species, but it fails with asexual taxa (e.g. bacteria, and many groups of asexual protists). In this case, the Evolutionary Species Concept (ESC), which identifies a species as a lineage of populations derived from a single ancestor may be more useful. This is also useful for defining species in extinct taxa.
SPECIFIC EPITHETNPSYSTEMATICSPronunciation: spa-SI-fik E-pe-thet

Etymology: Specific is an adjectival form of species. Epithet is derived from the Greek word epithetos (ἐπίθετος), which means added to.

The specific epithet is the Latinized adjective that is added to the genus to make the specific name. Note that the species name requires both the genus and specific epithet according to the rules of binomial nomenclature.
SPERMNANIMALS, PLANTS, PROTISTSClick here
SPERMATIANPLANTS, FUNGIPronunciation:

Etymology:

Spermatia are the nonmotile “sperm” or microgametes in the red algae.
SPERMATOPHORENANIMALSPronunciation:

Etymology:

A spermatophore is a gelatinous packet of sperm, which is transferred to another in the process of mating. This occurs in many invertebrates.
SPICULENANIMALS
SPIKENPLANTSPronunciation:

Etymology:

An indeterminate inflorescence with sessile flowers.
SPIKELETNPLANTSPronunciation:

Etymology:

Unit of the inflorescence in grasses. Consists of one or more flower, subtended by a common pair of glumes.
SPIRACLENANIMALSPronunciation:

Etymology:

Spiracles are openings on the abdominal segments of insects and body segments of myriapods through which air enters the tracheal system. It also is a small circular gill slit in some chondrichthyes.
SPIRALADJBACTERIAPronunciation:

Etymology:

A spiral is a cell form that is a cork-screw shaped rod.
SPIRAL CLEAVAGENPANIMALSPronunciation:SPI-r’l KLE-vegh

Etymology: The phrase, spiral cleavage, comes from two very different sources. Spiral is from the Greek to mean the coil or twist of a snake (speira, σπείρα). Cleavage is from the Old English cleofan, which means to split.

Spiral cleavage is typical of the Protostomata and is characterized by the division planes of early cytokinesis products of the zygote being oblique to the plane of the polar axis. This produces unequal cells in the developing blastula. Usually spiral cleavage is determinant.
SPONGINNANIMALSPronunciation:SPI-r’l KLE-vegh

Etymology: The phrase, spiral cleavage, comes from two very different sources. Spiral is from the Greek to mean the coil or twist of a snake (speira, σπείρα). Cleavage is from the Old English cleofan, which means to split.

Spiral cleavage is typical of the Protostomata and is characterized by the division planes of early cytokinesis products of the zygote being oblique to the plane of the polar axis. This produces unequal cells in the developing blastula. Usually spiral cleavage is determinant.
SPONGOCOELNANIMALSPronunciation:

Etymology:

The spongocoel is the central cavity of a sponge. Ostia lead into it and a osculum leads out of it.
SPORANGIUM (SPORANGIA)NPLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

Sporangia are spore-bearing structures.
SPORANGIOPHORENPLANTSPronunciation:

Etymology:

Sporangiophores are fertile appendages that do not look leaf-like. The sporangiophores of the horsetails may be compound structures. See strobilus.
SPOROGENESISNPLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

Sporogenesis is spore production. Usually, spores are distributive propagules, but sometimes they can serve as resting stages. Spores are the immediate products of meiosis in embryophyte plants.
SPOROGENYNPROTISTSPronunciation:

Etymology:

Sporogony is the multiple mitosis and cytokinesis of a zygote without an increase in cell size. It can also be involved in the meiosis and subsequent mitosis (with cytokinesis) to produce spores within the zygote.
SPOROPHYTENPLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

A sporophyte is the diploid phase of an organism that exhibits alternation of generation. This phase produces spores usually in specialized sporangia as the immediate products of meiosis.
SPOROPLASMNPROTISTSPronunciation:

Etymology:

Ameba-like portion of a microsporidian cyst that is infective to the next host.
SPOROZOITENPROTISTSPronunciation:

Etymology:

Sporozoites are the infective stages that are the products of sporogony in apicomplexans.
SPUR SHOOTNPPLANTSPronunciation:

Etymology:

A slow growing, highly reduced shoot.
SQUAMULOSEADJPLANTSPronunciation:

Etymology:

Scaly
STABILIZING SELECTIONNPEVOLUTIONPronunciation: STA-bi-li-zing se-lek-shun

Etymology: Stabilizing (selection is defined elsewhere) comes from the adjective stable, which is derived from the Latin stabilis (firm or steadfast).

Stabilizing selection is a form of selection for the mean value of a trait. That is, individuals with extreme phenotypes have lower fitness.
STALK CELLNPPLANTSPronunciation:

Etymology:

One of the products of division of the initial cells in the pollen of some gymnosperms, said to be the homologue of the antheridial stalk.
STAMENNPLANTSPronunciation:

Etymology:

One of the male sex organs, usually consisting of anther and filament.
STATOBLASTNANIMALSPronunciation:

Etymology:

A statoblast is an asexual (and over-wintering) reproductive structure produced by certain ectoproct bryozoans.
STATOSPORENPronunciation:

Etymology:

Statospores are resting spores (zygospores) produced by chrysophytes and xanthophytes. They are produced within the cell and have a plug of organic material in the chrysophytes.
STERIGMA (STERIGMATA)NFUNGIPronunciation:

Etymology:

A slender projection of the basidium where spores are attached.
STERNUM (STERNA OR STERNUMS)NANIMALSPronunciation:

Etymology:

A sternum is the breastbone in vertebrates and the ventral plate of an arthropod body segment.
STEROLNANIMALS, PLANTS, PROTISTS, FUNGI, BACTERIAPronunciation:

Etymology:

Sterols are ubiquitous as components of membranes in eukaryotes and a few prokaryotes. Cholesterol is a common animal sterol.
STIGMA (STIGMATA)NPLANTS, PROTISTSPronunciation:

Etymology:

The apex of the style, usually enlarged, on which the pollen grains land and germinate.
STIPENPROTISTS, FUNGIPronunciation:

Etymology:

Supporting stalk of a mushroom cap.
STIPULENPLANTSPronunciation:

Etymology:

A leafy outgrowth, often in pairs, at the base of the petiole.
STOMATE (STOMATA)NPLANTSPronunciation:

Etymology:

Pores in the leaf epidermis surrounded by a pair of guard cells. The gas exchange of leaves is controlled by the dimension of the pores.
STOMOCHORDNANIMALSPronunciation:

Etymology:

A stomochord is a notochord-like structure in the preoral lobe of hemichordates.
STOMODAEUM (STOMODAEA)NANIMALSPronunciation:

Etymology:

A stomodaeum is a kind of foregut in certain coelentrates, insects, etc. It is lined with ectoderm rather than endoderm.
STRAMENOPILENPROTISTSPronunciation:

Etymology:

Stramenopile is a term used for an organism with a heterokont cell.
STRIA (STRIAE)NPROTISTSPronunciation:

Etymology:

Striae are rows of punctae (holes) that give the appearance of a straight line.
STRIATED FLAGELLAR ROOTSNPPLANTS, PROTISTSPronunciation:

Etymology:

Striated roots (also called kinetodesma, banded roots, kinetodesmal fibers, or striated fibers) are banded flagellar roots that elaborate from basal bodies. They form a distinctive and diagnostic network in the Ciliata.
STROBILA (STROBILAE)NANIMALSPronunciation:

Etymology:

Strobila (strobilae, pl.) are structures that bud medusae in certain Cnidarians. Also, a strobila is the name of the pseudosegmented proglottid portion of a tapeworm.
STROBILUS (STROBILI)NPLANTSPronunciation:

Etymology:

A strobilus is an axis of fertile appendages. A simple strobilus is an axis of sporophylls. A compound strobilus is an axis of simple fertile axes. Sometimes the compound cones have simple fertile axes that are reduced to a single sporophyll and appear to be simple strobili.
STROMA (STROMATA)NFUNGIPronunciation:

Etymology:

A communal tissue in which multiple perithecia are embedded.
STYLENPLANTSPronunciation:

Etymology:

The elongated potion of a carpel that bears the stigma at its tip.
STYLETNANIMALSPronunciation:

Etymology:

A dagger-like structure.
SUBAPICALLY-INSERTED FLAGELLANPPLANTSPronunciation:

Etymology:

Flagella are subapically inserted when their insertion point is lateral to the apex or anterior end of the cell.
SUBPOLAR FLAGELLUM (SUBPOLAR FLAGELLA)NPANIMALSPronunciation:

Etymology:

Subpolar flagella are inserted near but not on the end of a rod or spiral cell.
SULCUS (SULCI)NPROTISTSPronunciation:

Etymology:

A sulcus is a longitudinal groove (from the cingulum to the posterior end of the dinoflagellate cell and in which lies the trailing whiplash flagellum.
SUNKEN STOMATE (SUNKEN STOMATA)NPLANTSPronunciation:

Etymology:

When the guard cell pairs of a single stomate are positioned below the surface of the epidermis.
SUPERFICIAL CLEAVAGENPANIMALSPronunciation:

Etymology:

Superficial cleavage is the incomplete and unequal cleavage of the zygote.
SUTURENANIMALS, PROTISTSPronunciation:

Etymology:

A suture is an immovable joint (e.g. in the bones of the vertebrate skull and the shells of chambered cephalopod mollusks).
SWARMER CELLNPPROTISTSPronunciation:

Etymology:

Swarmer cells are motile propagules that are usually produced in specialized asexual structures.
SYMBIOTICADJECOLOGYPronunciation:

Etymology:

Symbiotic (adj.) literally means “living together”. Its usual meaning is that two species have a necessary association. However, strictly applied symbiosis varies from parasitism, to commensalism, to mutalism.
SYMPATRIC SPECIATIONNPEVOLUTIONPronunciation: sim-PAT-rik

Etymology: Sympatric (speciation is defined elsewhere) is derived from two Greek roots that mean together with (syn, σύν) and fatherland (patrida, πατρίδα). The reference is to populations that occupy the same fatherland or geographic range.

Sympatric speciation can occur in populations with overlapping geographic ranges. A large breeding population can form a daughter species in the absence of an external barrier if the barrier becomes genetic. See also Allopatric Speciation, Peripatric Speciation, and Isolating Mechanisms.
SYNANGIUM (SYNANGIA)NPLANTSPronunciation:

Etymology:

A Synangium is a structure made of two or more eusporangia fused together.
SYNAPOMORPHYNEVOLUTIONClick here
SYNCARPOUSADJPLANTSPronunciation:

Etymology:

Having united carpels
SYNCONOIDADJ AND NANIMALSPronunciation:

Etymology:

A sponge type that has ostia connected to choanocyte-lined chambers that open directly into the spongocoel.
SYNCYTIUM (SYNCYTIA)NANIMALS, PLANTS, PROTISTS, FUNGIClick here
SYNPLESIOMORPHYNSYSTEMATICSPronunciation: sin-PLE-zi-o-mor-fi

Etymology: Synplesiomorphy has the Greek prefix syn- (συν) added to plesiomorphy. The reference is to a organisms having shared plesiomorphic or primitive characters.

Synplesiomorphy is the condition when organisms share primitive or plesiomorphic character states. This is not evidence of evolutionary relationships between taxa. It just means that they share a common ancestral form.
SYSTEMATICSNSYSTEMATICSPronunciation: sis-te-MA-tiks

Etymology: Systematics is derived from system, which comes from the Greek, systima (σύστημα) and means the whole or a body.

Systematics (n.) is the branch of biology that deals with the classification of living organisms, usually as a natural grouping. Thus, systematic biology is one of the most important disciplines for understanding biological diversity.

In general, it includes:
– taxonomy (naming organisms)
– classification (assigning taxa to groups that reflect their relationships)
– molecular biology
– biochemistry
– genetics
– ecology
– paleontology
– cell biology
– anatomy
– developmental biology
– evolution

Current schools of Systematics include Numerical Taxonomy (Phenetics) and Phylogenetic Taxonomy (Cladistics).
SYZYGYNPROTISTSPronunciation:

Etymology: from the Greek σύζυγος (syzygos), “‘yoked together’”.

Syzygy is the association of gamonts in certain apicomplexans before gamete formation and fusion.
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