Final answer:
The offspring resulting from the union of two haploid gametes with different alleles is called heterozygous, which contributes to genetic diversity and determines physical traits.
Step-by-step explanation:
When two haploid gametes contain two different alleles of a given gene, the resulting offspring is called heterozygous.
During sexual reproduction, haploid gametes from two parents combine at fertilization to create a diploid zygote. Each gamete contributes one allele for each gene. Alleles are different versions of the same gene that may result in different traits. If the two alleles are identical, the organism is homozygous for that trait. However, if the alleles are different, one from each parent, the organism is considered heterozygous. This heterozygosity creates genetic diversity within a species.
For example, if one parent contributes an allele for blue flower color and the other contributes an allele for red flower color, the resulting genotype of their offspring would be heterozygous, represented as one allele for blue and one for red (e.g., Bb). This genetic composition is critical for traits that follow Mendelian inheritance patterns, where the different allele combinations can determine the physical appearance, or phenotype, of the organism.