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H

TERMGROUPDEFINITION
HAEMERYTHRINNANIMALSPronunciation:

Etymology:

A respiratory pigment (contains iron) used for respiration in many invertebrates.
HAEMOCOELNANIMALSPronunciation:

Etymology:

A haemocoel is the primary body cavity of arthropods and related organisms. It is characteristic of organisms with an open circulatory system in which the blood “circulates” in a large open sinus that surrounds the organs.
HAEMOCYANINNANIMALSPronunciation:

Etymology:

Haemocyanin is a respiratory pigment characteristic of arthropods and annelids. It is a protein complexed with copper, which is blue in the oxidized state.
HAPLOPHASENPLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

Portion of life cycle during which the organism is haploid.
HAPTONEMA (HAPTONEMATA)NPROTISTSPronunciation:

Etymology:

A haptonema is a flagellum-like structure that characterizes the Haptotista. The formula for the axonemal microtubular array is 6(1)+0. Usually functions as a holdfast.
HAUSTORIUM (HAUSTORIA)NPLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

Modified hyphae of parasitic fungi that penetrate host cell.
HEADNANIMALS, PLANTSPronunciation:

Etymology:

A short dense spike of flowers.
HEPATOPANCREASNANIMALSPronunciation:

Etymology:

The hepatopancreas is the is a gland in many invertebrate groups that releases digestive enzymes and functions as a liver.
HERMAPHRODITENANIMALSPronunciation:

Etymology:

An animal that bears both male and female gonads.
HESPERIDIUM (HESPERIDIA)NPLANTSPronunciation:

Etymology:

A berry in which the fleshy part is divided into segments and the skin is a tough leathery rind.
HETEROCYSTNBACTERIAPronunciation:

Etymology:

Heterocysts are special cells in certain Cyanobacteria that have the ability to fix nitrogen into a biologically usable form. The heterocysts have a morphology that is different from the vegetative cells (usually nearly clear) and generate ATP through photophosphorylation to drive the enzymatic energy necessary to fix nitrogen.
HETERODYNAMIC FLAGELLANPPROTISTSPronunciation:

Etymology:

Heterodynamic flagella occur on the same cell but beat with different patterns (e.g. anterior-posterior).
HETEROMORPHIC ALTERNATION OF GENERATIONNPANIMALS, PLANTS, PROTISTS, FUNGIPronunciation:

Etymology:

Heteromorphic alternation of generation occurs in organisms in which the haploid gametophyte phase and diploid sporophyte phase are different in form.
HETEROSPOROUSADJPLANTSPronunciation:

Etymology:

Heterosporous plants have sporangia that produce spores of different sizes: megaspores (large) and microspores (small). Megaspores produce archegoniate gametophytes, and microspores produce antheridial gametophytes.
HINDGUTNANIMALSPronunciation:

Etymology:

The hindgut is the posterior portion of the gut that is lined by ectoderm.
HISTONENANIMALS, PLANTS, PROTISTS, FUNGI, BACTERIAPronunciation:

Etymology:

Histones are particular basic proteins associated with DNA in almost all eukaryotes and one or a few prokaryotes (e.g. Thermoplasma).
HOLASPIDADJ OR NANIMALSPronunciation:

Etymology:

The holaspid (adj.) developmental stage of trilobites was the stage at which the number of body segments does not change, but successive molts allow for increasing body size.
HOLDFASTNPLANTS, PROTISTSPronunciation:

Etymology:

A holdfast is a root-like attachment structure that is characteristic of seaweeds, particularly the kelps.
HOLLOW NERVE CORDNPANIMALSPronunciation:

Etymology:

A hollow nerve cord develops from the the invagination of the ectoderm.
HOLOBASIDIUM (HOLOBASIDIA)NFUNGIPronunciation:

Etymology:

Made of a single cell, more or less club-shaped, with sterigmata that are fairly small relative to the basidium.
HOLOBLASTICADJANIMALSPronunciation:

Etymology:

Holoblastic (adj.) describes the type of cleavage in which the zygote divides by complete cytokinesis.
HOLOCARPICADJFUNGIPronunciation:

Etymology:

Entire thallus functions as sporangium.
HOMOPLASYNEVOLUTIONPronunciation: ho-mo-PLA-zi

Etymology: Homoplasy is derived from two Greek roots which mean the same (homo, ομοσ) and to mold (plassein, πλασσειν).

Homoplasy means that the similarity between taxa is due to independent evolutionary change (e.g. convergent evolution).
HOMOSPOROUSADJPLANTS, PROTISTSPronunciation:

Etymology:

Homosporous (adj) plants produce one type of spore.
HORMOGONIUM (HORMOGONIA)NBACTERIAPronunciation:

Etymology:

Hormogonia are short fragments of trichomes contained within a common sheath. They are formed by the death of periodic vegetative cells in the trichome. Hormogonia can be a means of asexual reproduction in Cyanobacteria.
H-PIECENPPLANTS, PROTISTSPronunciation:

Etymology:

H-Pieces are segments of cell walls that overlap. They can be found in some filamentous species of the xanthophytes and green algae.
HYDROGENOSOMENPROTISTSPronunciation:

Etymology:

Hydrogenosomes are symbiotic bacteria or organelles that generate hydrogen as a kind of anaerobic mitochondrion.
HYDROIDNANIMALSPronunciation:

Etymology:

Specialized water-carrying cells found in bryophytes. May have been the precursor vascular tissue.
HYDROSTATIC CAVITYNPANIMALSPronunciation:

Etymology:

A hydrostatic cavity is a fluid-filled cavity that provides support by muscular contraction of the surrounding tissue.
HYDROZOIDNANIMALSPronunciation:

Etymology:

The gastrozoid is the feeding animal in a colonial organism, particularly in colonial Hydrozoans in which some are modified for other things like asexual reproduction (Gonozoids).
HYMENIUM (HYMENIA)NFUNGIPronunciation:

Etymology:

Spore-bearing layer of cells, which contain asci, found in certain fungi.
HYPOGENOUSADJPLANTSPronunciation:

Etymology:

With the sepals, petals, and stamens attached to the receptacle or axis below the ovary.
HYPOTHECA (HYPOTHECAE)NPROTISTSPronunciation:

Etymology:

The hypotheca is the portion of the dinoflagellate cell that lies posterior to the cingulum.
HYPOVALVENPROTISTSPronunciation:

Etymology:

A hypovalve is the smaller of the two overlapping valves of diatoms.
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