Biology Reference
In-Depth Information
ical level by relationships or factors that, if continued, are likely to lead to
extinction.
Endotoxin.
A toxic compound that is produced inside a microorganism
and is released only when the microorganism dies and breaks down.
Epistasis.
The influence of alleles at one locus on the expression of alle-
les at a different locus.
Extinction.
The disappearance of a species due to mortality that exceeds
reproduction until the last individual dies or to the loss of genetic iden-
tity due to interbreeding with other species.
Extirpation.
The local extinction of part of the overall population of a
species.
Extrafloral nectaries.
Nectar-producing structures occurring on plant
parts other than flowers.
Fitness.
The evolutionary success of an organism with a particular
genetic makeup as measured by its contribution to the gene pool of sub-
sequent generations.
Forb.
A broad-leaved herbaceous plant.
Founder effect.
The biased representation of genetic variability of a
colonist population due to the fact that colonizing individuals carry only
a fraction of the variability of the parental population.
Furanocoumarins.
Complex chemicals produced by certain plants of
the carrot family as defenses against herbivores.
Fynbos.
The evergreen shrubby vegetation type of areas of Mediter-
ranean climate in South Africa.
Genetic bottleneck.
The loss of alleles of genes by genetic drift during
periods when the effective breeding population of a species has been
maintained at a low level for several to many generations.
Genetic drift.
The change in frequency of different alleles of a gene due
to random factors affecting the reproduction of individuals contributing
alleles to offspring of subsequent generations.
Genetic swamping.
The loss of genetic distinctiveness of a species or
population by extensive interbreeding with other species or populations.
Genome.
The total genetic constitution of an organism.
