Environment: Polluted Forest Moths ReleasedG1G2G3G4G5 Typica 125 88 83 76 29 Carbonaria 510 735 885 1042 1406 Total 635 823 968 1118 1435 Phenotype Frequency ColorInitial FrequencyFrequency G5 Typica Light 9 Carbonaria Dark Allele Frequency AlleleInitial Allele FrequencyG5 Allele Frequency q d p D Genotype Frequency MothsGenotypeColorMoths ReleasedInitial FrequencyFrequency G5Number of Moths G5 q2 Typica dd Light 2pq Carbonaria Dd Dark p2 Carbonaria DD Dark

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation:

they fuse to form they have half as many chromosomes as a somatic cell of the same individual. b