Encyclopedian Dictionary: June 2013

adnate

Pronunciation key

( ad′nāte )

ad•nate

adj.

[L. adnatus pp. of adnasci to be born, to grow to or on].

In botany and zoology, congenitally joined together. Said with regard to fused, unlike parts such as stamens and petals; see CONNATE.

References

adhesion

Pronunciation key

( əd-hē′zhən )
( ad-hē′zhən )

ad•he•sion

[Fr.; L. adhaesio < pp. of adhaerere see ADHERE].

Sticking together or being stuck together.
A sticking together of dissimilar materials.
Adherence; to some thing, a devoted attachment.
That which adheres.
In medicine when normally separate tissues grow together.
pl. bands of fibrous tissues by which such tissues are connected.
In physics, the force or forces that hold together the dissimilar molecules of substances whose surfaces are in contact: differentiated from cohesion.

References

adenosine phosphate

adenosine phosphate

(di-, tri-).

Called ATP. It is a major source of usable chemical energy in metabolism. On hydrolysis ATP loses one phosphate to become adenosine diphosphate (ADP) with release of usable energy.

References

adenine

Pronunciation key

( ad′ə-nēn′ )
( ad′ə-nin′ )
( ad′ə-nīn′ )

ad•e•nine

[aden- + ine].

White, crystalline purine base. C₅H₅N₅ derived from nucleic acid formed in organs such as the pancreas and spleen. It is present in DNA, RNA and nucleotides such as ADP and ATP.

References

adaptive radiation

Pronunciation key

( ə-dap′tiv rā′di-ā′shən )

adaptive radiation

The evolution from one form of organism to divergent forms with specialized physiology and distinctive behaviors suiting them for new and diverse ways of life.

References

adaptation

Pronunciation key

( ad′əp-tā′-shən )
( ad′ap-tā′shən)

ad•ap•ta•tion

[Fr.; LL. adaptatio, see ADAPT.; L. aptus fit, Fr. adaptare, to fit].

Adapting or being adapted.
A thing which results from becoming adapted such as a play being an adaptation of a novel.
In biology, a change in structure, development of a peculiar characteristic in an organism's physiology or behavior which better enables it to better fit in and survive in its particular environment.
In physiology, the power the eye has of adjusting to variations in light.
In sociology, a change in behavior to conform to cultural patterns.

References

ad-

ad-

[L. toward, to].

Prefix that means "toward" or "to".

References

active transport

active transport

A process which expends energy when a cell moves a substance across its membrane, typically from a position of low concentration to a point of higher concentration, against the diffusion gradient.

References

action spectrum

action spectrum

Waves from among the light spectrum which a responsive reaction is elicited.

References

actinomorphic

Pronunciation key

( ak′ti-nə-môr′fik )

ac•ti•no•mor•phic

adj.

[Gk. aktis, ray + morphe form].

In biology, having radical symmetry as a starfish or flower that can be divided equally in half in more than one longitudal plane.

References

acid

Pronunciation key

( as′id )

ac•id

adj.

[L. acidus, sour < base ac-, sharp].

Sour; sharp and biting to taste; tart.
Substance that dissociates, releasing hydrogen (H^-) ions but not hydroxyl (OH⁺) ions, having a pH of less than 7. see base.
In chemistry, a compound that can react with a base to form a salt, the hydrogen of the acid being replaced by a positive ion; according to modern theory, a compound yielding hydrogen ions (protons) to a base in a chemical reaction: in water solution, an acid tastes sour, turns blue litmus red, and, according to the dissocation theory it produces free hydrogen ions.

Syn. SOUR

References

achene

Pronunciation key

( ā-kēn′ )

a•chene

[Gk. a-, not, + chainein to gape].

Any small, dry fruit with a single seed whose thin outer coat (pericarp) does not burst when ripe.

References

accessory pigment

accessory pigment

Pigment which captures light energy and converts it into chlorophyll a.

References

absorption spectrum

Pronunciation key

( ăb·sôrp′shŭn spĕk′trŭm )

ab•sorp•tion spec•trum

Spectrum light waves which are absorbed by a particular pigment.

References

abscission zone

Pronunciation key

( ăb·sizh′ŭn )

abscission zone

A delicate layer of thin-walled cells which extend across the stem of a leaf or fruit, and breaking of which results in the organ to separate from the plant.

References

abscission

Pronunciation key

( ab-sizh′ən )
( ab-sish′ən )

ab•scis•sion

[L. abscissio see ABSCISSA].

A cutting off such as by surgery.
Abrupt stop, such as in mid-sentence for rhetorical effect.
The dropping of leaves, flowers, fruit or other parts of the plant normally following the formation of an abscission zone.

References

abscisic acid

abscisic acid

[L. abscissus cut off].

Plant hormone which is involved in abscission and dormancy.

References

Å ( abbreviation )

Pronunciation key

( ăng′strŭm )

After A.J. Angstrom, a swiss physicist (1814-1874). A unit of length equal to .0001 of a micron; Abbreviation Å.

References

Thallophyta

Thallophyta

"In systems in which the algae and fungi are regarded as plants, they are often grouped as a subkingdom Thallophyta, the thallophytes: organisms with no highly differentiated tissues, such as root, stem, or leaf, and no vascular tissues (xylem and phloem). The land plants are then grouped into a second subkingdom, Embryophyta, in which the zygote develops into a multicellular embryo still encased in an archegonium or an embryo sac. All embryophytes are marked by alternation of generation.
Although they are no longer used in schemes of classification, terms such as "algae," "thallophytes," and "gymnosperms" are still sometimes useful in an informal sense. An even earlier scheme divided all plants into "phanerogams," those with flowers, and "cryptogams," those lacking flowers; these terms are occasionally seen today also."
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

In the first aquatic plants, tissues for support and conduction (vascular) were not necessary. On land, fundamental adaptations were necessary to transport nutrients throughtout the organism's body. With the development of pollen and seeds in gymnosperms the dependence of plants on water for fertilization was eliminated enabling new species to thrive and become more widely distributed on land.

In light of their evolution the relationships among the different groups of non-flowering plants is not fully known. The illustration represents several points of view fused into a singular one. Mosses, Liverworts and Hornworts are placed with Embryophytes. Ferns, Gymnosperms, Club Mosses and Horsetails are grouped as Vascular Plants.

The plant body of a Thallophyte is a thallus, which may consist of a single cell or large mass of undifferentiated cells that show negligible specializations except those related to reproduction. Thallophytes lack conductive (vascular) tissue. They possess no roots, stems, leaves and do not produce flowers, seeds or fruits.

Typically they have single cell reproductive structures. Those that are multi-cellular lack a jacket of sterile cells around sex cells and around the spores. Stoneworts were an exception. The fertilized egg or zygote of Thallophytes do do not develop into an embryo. Also, reproduction occurs asexually by cell division or through formation of spores of many types, motile and non-motile.

References and Further Reading

Zoology Quest: Embryophyte

Angiospermae

Angiospermae

The itis.gov database lists two entries for Kingdom Plantae:

Angiospermae – not accepted.
Angiospermae – accepted – angiosperma, angiospermes, angiosperms, flowering plants.

"The flowering plants. Seed plants in which the ovules are enclosed in a carpel (in all but a very few genera), and the seeds at maturity are born within fruits. They are extremely diverse vegetatively but characterized by the flower, which is basically insect-pollinated. Other modes of pollination, such as wind pollination, have been derived in a number of different lines. The gametophytes are much reduced, with the female gametophyte often consisting of only eight cells or nuclei at maturity. Double fertilization involving two of the three nuclei from the mature microgametophyte gives rise to the zygote and to the primary endosperm nucleus; the former becomes the embryo and the latter a special nutritive tissue, the endosperm. Among the pterophytes, multicellular archegonia characterize all gymnosperms except for two genera of the class Gnetinae. There are about 250,000 species."
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

Taxonomic Hierarchy
Kingdom	Plantae – Vegetal, plants
Subkingdom	Viridaeplantae – green plants
Infrakingdom	Streptophyta – land plants
Division	Tracheophyta – vascular plants, tracheophytes
Subdivision	Spermatophytina – spermatophytes, seed plants
Infradivision	Angiospermae – flowering plants, angiosperms
Direct Children:
Class	Magnoliopsida

References

Angiospermae, Taxonomic Serial No.: 846505

Gnetinae

Gnetinae

"Seed plants of three very distinctive genera with the inner layers of the integument prolonged into a tube. The only gymnosperms in which vessels occur. There are about 70 species."

References

Ginkgoinae

Ginkgoinae

The term "Ginkgoinae" does not appear in the itis.gov database, it appears that Ginkgoinae may be a synonym of the accepted name which remains to be listed. The accepted names are found below in the taxonomic hierarchy table.

"Ginkgo. Seed plants with active cambial growth and fan-shaped leaves with open dichotomous venation. The ovules are not enclosed and are fleshy at maturity. Sperm are carried to the vicinity of the ovule in a pollen tube, but are flagellated and motile. They are gymnosperms. There is one species only."
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

Taxonomic Hierarchy

Kingdom	Plantae – Vegetal, plants
Subkingdom	Viridaeplantae – green plants
Infrakingdom	Streptophyta – land plants
Division	Tracheophyta – vascular plants, tracheophytes
Subdivision	Spermatophytina – spermatophytes, seed plants
Infradivision	Gymnospermae – gymnosperms
Class	Ginkgoopsida – ginkgo
Order	Ginkgoales
Family	Ginkgoaceae
Genus	Ginkgo L. – ginkgo
Species	Ginkgo biloba L. – maidenhair tree, common ginkgo

References

Ginkgo biloba, L., Taxonomic Serial No.: 183269

Zoology Quest: Ginkgo biloba

Cycadinae

Cycadinae

"Cycads. Seed plants with sluggish cambial growth and pinnately compound, palmlike or fernlike leaves. The ovules are not enclosed. The sperm are flagellated and motile, but are carried to the vicinity of the ovule in a pollen tube. Cycads are gymnosperms. There are nine genera and about 100 species."

References

Coniferinae

Coniferinae

The conifers. Seed plants with active cambial growth and simple leaves, in which the ovules are not enclosed and the sperm are not flagellated. There are some 50 genera and about 550 species, the most familiar group of gymnosperms.

References

Filicineae

Filicineae

"The ferns. They are mostly homosporous although some are heterosporous. The gametophyte is more or less free-living and usually photosynthetic. Multicellular gametangia and free-swimming sperm are present. There are about 11,000 species."

References

Pterophytina

Pterophytina

"Ferns, gymnosperms, and flowering plants. Although diverse, these groups possess in common the megaphyll, which in certain genera has become much reduced. There are about 260,000 species."

References

Sphenophytina

Sphenophytina

"The horsetails. Homosporous vascular plants with jointed stems marked by conspicuous nodes and elevated siliceous ribs and sporangia borne in a strobilus at the apex of the stem. Leaves are scalelike. Sperm are motile. ALthough now thought to have evolved from a megaphyll, the leaves of the horsetails are structurally indistinguishable from microphylls. There is one genus, Equisetum, with about two dozen living species."

References

Lycophytina

Lycophytina

"The lycophytes. Homosporous and heterosporous vascular plants with microphylls; extremely diverse in appearance. All lycophytes have motile sperm. There are five genera and about 1,000 species."

References

Tracheophyta

Tracheophyta

"The vascular plants. Terrestrial plants with complex differentiation of organs into leaves, roots, and stem. Motile cells, if present, (and then only in the form of male gametes) are elongate or (if wound up) top-shaped, propelled by many cilia. The vascular plants have well-developed strands of conducting tissue for the transport of water and organic materials. The main trends of evolution in the vascular plants involve a progressive reduction in the gametophyte, which is green and free-living in ferns but heterotrophic and more or less enclosed by sporophytic tissue in the others; the loss of multicellular gametangia and motile sperm; and the evolution of the seed."
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

Taxonomic Hierarchy
Kingdom	Plantae – Vegetal, plants
Subkingdom	Viridaeplantae – green plants
Infrakingdom	Streptophyta – land plants
Division	Tracheophyta – vascular plants
Direct Children:
Subdivision	Pteridophytina – pteridophytes
Subdivision	Spermatophytina – spermatophytes, seed plants

References

Tracheophyta, Taxonomic Serial No.: 846496

Musci

Musci

Presently, Musci, Taxonomic Serial No.: 500008 is no longer accepted. The current accepted name is Bryophytina, Taxonomic Serial No.: 846121

"The mosses. The gametophytes are leafy. Sporophytes have complex patterns of dehiscense. Rhizoids are multicellular. Stomata are present on the sporophyte. There are about 14,500 species."

References

Antherocerotae

Antherocerotae

"The hornworts. The gametophytes are thallose. The sporophyte grows from a basal intercalary meristem for as long as conditions are favorable. Stomata are present on the sporophyte. There are about 100 species."

References

Hepaticae

Hepaticae

Presently, Hepaticae, Taxonomic Serial No.: 14196 is no longer accepted. The accepted classification is Marchantiophytina, Taxonomic Serial No.: 846120

"The liverworts. The gametophytes are thallose or leafy rhizoids, single-celled and the sporophytes relatively simple in construction. There are about 9,000 species.
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

References

Hepaticae, Taxonomic Serial No.: 14196

Bryophyta

Bryophyta

"Mosses, hornworts and liverworts. Multicellular plants with the photosynthetic pigments and food reserves similar to those of the green algae. They have gametangia with a multicellular sterile jacket one cell layer thick. The sperm are biflagellate and motile. Gametophytes and sporophytes both exhibit complex multicellular patterns of development, but the conducting tissues are usually completely absent and not well differentiated when present. Most of the photosynthesis in these primarily terrestrial plants is carried out by the gametophyte, upon which the sporophyte is initially dependent. There are more than 23,500 species."
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

Taxonomic Hierarchy
Kingdom	Plantae – Vegetal, plants
Subkingdom	Viridaeplantae – green plants
Infrakingdom	Streptophyta – land plants
Division	Bryophyta – hornworts, mosses, non-vascular land plants
Direct Children:
Subdivision	Anthocerophytina – hornworts
Subdivision	Bryophytina – mosses
Subdivision	Marchantiophytina – liverworts

References

Bryophyta, Taxonomic Serial No.: 14189

Chlorophyta ( Infrakingdom ) and ( Division )

Chlorophyta

"Green algae. Unicellular or multicellular plants characterized by chlorophylls a and b and various carotenoids. The carbohydrate food reserve is starch. Motile cells have two whiplash flagella at the apical end. True multicellular genera do not exhibit complex patterns of differentiation. Multicellularity has arisen at least three times, and quite possibly more often. There are about 7,000 known species and possibly many more."
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

Taxonomic Hierarchy
Kingdom	Plantae – Vegetal, plants
Subkingdom	Viridaeplantae – green plants
Infrakingdom	Chlorophyta – green algae
Division	Chlorophyta – green algae
Direct Children:
Subdivision	Chlorophytina

Chlorophyta, Taxonomic Serial No.: 5414

Chlorophyta, Taxonomic Serial No.: 846493

Taxonomic Hierarchy
Kingdom	Plantae – Vegetal, plants
Subkingdom	Viridaeplantae – green plants
Infrakingdom	Chlorophyta – green algae
Direct Children:
Division	Chlorophyta – green algae

References

Chlorophyta, Taxonomic Serial No.: 5414

Chlorophyta, Taxonomic Serial No.: 846493

Fungi Imperfecti

Fungi Imperfecti

"Mainly fungi with the characteristics of Ascomycetes but in which the sexual cycle has not been observed; a few probably belong to other classes. The Fungi Imperfecti are classified by their asexual spore-bearing organs. There are some 25,000 species."
Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971

Fungi Imperfecti

References

Zoology Quest: Thallophyta