Follicle-stimulating hormone (FSH)
A protein hormone secreted by the anterior pituitary that stimulates the production of eggs
by the ovaries and sperm by the testes.
Fontana
A city of southern California west of San Bernardino. It is an industrial center in a citrus-
growing area. Population: 170,000.
Food chain
The pathway along which food is transferred from trophic level to trophic level, beginning
with producers.
Food web
The elaborate, interconnected feeding relationships in an ecosystem.
Foregut
The anterior alimentary canal in a vertebrate embryo, including those parts which will
develop into the pharynx, esophagus, stomach, and anterior intestine.
Fossil
The remains of an organism, or direct evidence of its presence (such as tracks). May be an
unaltered hard part (tooth or bone), a mold in a rock, petrification (wood or bone),
unaltered or partially altered soft parts (a frozen mammoth).
Founder effect
A cause of genetic drift attributable to colonization by a limited number of individuals from
a parent population.
Fovea
A small area in the center of the retina in which cones are concentrated; the area of
sharpest vision.
Fragile X syndrome
A hereditary mental disorder, partially explained by genomic imprinting and the addition of
nucleotides to a triplet repeat near the end of an X chromosome.
Fragmentation
A method of asexual eprodection, occurring in some invertebrate animals, in which parts of
the organism break of and sunsequently differentiate and develop and new individuals. It
occurs especially in certain coelenterates and annelids.
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