a cell divisional process in which the chromosomes are duplicated
meiosis
a cell divisional process in which the chromosome number is reduced by half
diploid
having two sets of chromosomes
haploid
having one set of unpaired chromosomes
antheridium
the male sex organs of plants other than gymnosperms and angiosperms [pl. antheridia]
archegonium
the female sex organ of plants, other than angiosperms [pl. archegonia]
gametophyte
a haploid, gamete-producing plant in the alternation of generations
alternation of generations
the sequence of a haploid gametophyte and a diploid sporophyte during the course of a life cycle
sporophyte
a diploid, spore-producing plant in an alternation of generations
sorus
an area of spore production on the underside of a fern leaf [pl. sori]
microspore
a spore that develops into a male gametophyte
megaspore
a spore that develops into a female gametophyte
endosperm
food-storage tissue in seeds; created when the second sperm in the pollen tube unites with the female gametophyte cell that contains two haploid nuclei
dominant trait
a characteristic determined by a gene masking the expression of a comparable, but recessive gene
recessive trait
a genetic characteristic, the expression of which is masked by a comparable but dominant gene
heterozygous
having both dominant and recessive genes for a particular characteristic on homologous chromosomes
homozygous
having identical genes on homologous chromosomes
phenotype
the physical appearance of an organism; the visible expression of genes
genotype
the genetic constitution of an organism; the actual gene composition
aneuploidy
"not good"; a condition in which chromosome numbers are not in exact multiples of the haploid set; having extra or missing chromosomes within the nucleus
polyploid
having three or more sets of chromosomes per cell
homologous chromosomes
matching chromosome pairs
allopolyploid
a hybrid arising from the combination of chromosomes from two different species