added. He was a member or honorary member of
numerous societies in Scandinavia, Iceland, Russia, and
Germany. He received a Danish gold medal for merit,
and in 1904 the Cameron Prize was given to him from
the University of Edinburgh.
In 1892 Finsen married Ingeborg Balslev, the
daughter of Bishop Balslev at Ribe. They had four chil-
dren. Finsen died on September 24, 1904.
firefly Commonly called a lightning bug, they are
neither flies nor bugs. They belong to the order
Coleoptera, family Lampyridae, which are beetles.
These small flying beetles produce their own light, from
a chemical called luciferase, from structures in their
abdomen. Females of some species, which are wingless,
and many larvae also produce light and are called
glowworms. Fireflies can be seen in early summer (late
May), appearing at dusk. Males and females attract
each other with a flashing green light in their
abdomens. The wingless females flash from the ground
and the males look for them. There are more than
2,000 species of firefly in temperate and tropical envi-
ronments worldwide.
first law of thermodynamics Simply put, energy
can neither be created nor destroyed, only trans-
formed or transferred from one molecule to another;
in effect, the total amount of energy in the universe is
constant. Also known as the Law of Conservation of
Energy. Thermodynamics is the study of the conver-
sion of energy between heat and other forms, e.g.,
mechanical.
See alsoSECOND LAW OF THERMODYNAMICS.
fission(binary fission) Asexual reproduction or divi-
sion of a single-celled individual, such as a prokaryote,
into two new single-celled individuals of equal size and
genetic composition, without mitosis occurring. From
the Latin fissilis,meaning “easily split.”
fixation The complete prevalence of one gene form
(allele), resulting in the total exclusion of the other.
Genes that confer a reproductive advantage generally
go to fixation.
fixed action pattern(FAP) A series of innate behav-
ior patterns (a fixed action) in response to a specific
stimulus (called a sign stimulus or innate releaser) that
continues until the response is completed. FAPs are
genetic and not individually learned. For example, a
group of spined larvae of the buck moth (Hemileuca
maia) will all instantly raise their bodies and thrash
back and forth when a predator (bird) approaches.flaccid Limp, soft condition, e.g., walled cells are
flaccid in isotonic surroundings; low turgid pressure;
opposite of turgid.flagellum Along whiplike structure that is used to
propel certain kinds of prokaryote and eukaryote cells.
The cells can have an individual flagellum or a few
flagella per cell. In prokaryote organisms the flagellum
is composed of a protein called flagellin. In the eukary-
ote organism, it is longer than a CILIUMbut has the
same construction of nine outer double microtubules
and two inner single microtubules.flanking region The DNA sequences extending on
either side of a specific gene or locus; a region preced-
ing or following the transcribed region. The 3’ flanking
region (downstream flanking region) is found immedi-
ately distal (distant) to the part of a gene that specifies
the mRNA and where avariety of regulatory sequences
are located. The 3’ flanking region often contains
sequences that affect the formation of the 3’ end of the
message and may contain enhancers or other sites to
which proteins may bind. The 5’ flanking region flanks
the position that corresponds to the 5’ end of the
mRNA and is that part of DNA that precedes the tran-
scription-start site for a particular gene. The 5’ flanking
region contains the promoter (transcription control
region) and other enhancers or protein binding sites.flatworms Organisms that comprise the phylum
Platyhelminthes. These are normally hermaphroditic
organisms that have flat bodies and are bilaterally sym-
metrical, with defined head and tail, centralized ner-
vous system, and eyespots (light-sensitive cells). They
include flukes (trematodes), tapeworms (Cestoda), and130 firefly