Fig 7-1 Figure: 07-01 Caption: The life cycle of Chlamydomonas. Unfavorable conditions stimulate the formation of isogametes of opposite mating type that may fuse in fertilization. The resulting zygote undergoes meiosis, producing two haploid cells of each mating type. The photograph shows vegetative cells of this green alga.

Fig 7-2 Figure: 07-02 Caption: Illustration of mating types during fertilization in Chlamydomonas. Only when plus (+) and minus (-) cells are together will mating occur.

Fig 7-5 Figure: 07-05a Caption: (a) The Protenor mode of sex determination where the heterogametic sex (the male in this example) is XO and produces gametes with or without the X chromosome. The chromosome composition of the offspring determines its sex.

Fig 7-5 Figure: 07-05b Caption: (b) The Lygaeus mode of sex determination, where the heterogametic sex (again, the male in this example) is XY and produces gametes with either an X or a Y chromosome. The chromosome composition of the offspring determines its sex.

Fig 7-8 Figure: 07-08 Caption: The various regions of the human Y chromosome.

Fig 7-10 Figure: 07-10 Caption: Barr body occurrence in various human karyotypes, where all X chromosomes except one (N-1) are inactivated.

Fig 7-12 Figure: 07-12 Caption: Depiction of the absence of sweat glands (shaded regions) in a female heterozygous for the X-linked condition anhidrotic ectodermal dysplasia. The locations vary from female to female, based on the random pattern of X chromosome inactivation during early development, resulting in unique mosaic distributions of sweat glands in heterozygotes.

Fig 7-13 Figure: 07-13 Caption: Chromosome compositions, the ratios of X chromosomes to sets of autosomes, and the resultant sexual morphology in Drosophila melanogaster. The normal diploid male chromosome composition is shown as a reference on the left (XY/2A).

Fig 7-14 Figure: 07-14 Caption: A bilateral gynandromorph of Drosophila melanogaster formed following the loss of one X chromosome in one of the two cells during the first mitotic division. The left side of the fly, composed of male cells containing a single X, expresses the mutant white-eye and miniature-wing alleles. The right side is composed of female cells containing two X chromosomes heterozygous for the two recessive alleles.

Fig 7-15 Figure: 07-15 Caption: Three different patterns of temperature-dependent sex determination (TSD) in reptiles, as described in the text. The relative pivotal temperature  is crucial to sex determination during a critical point during embryonic development (FT 5 female-determining temperature; MT 5 male-determining temperature).

Figure: 07-15-01T01 Caption: snapping turtles and most lizards