Parental Generation (P):
Long-finned red guppy: LL RR (homozygous dominant for both genes)
Short-finned green guppy: ll rr (homozygous recessive for both genes)
Gametes:
Long-finned red guppy: LR, Lr, lR, lr
Short-finned green guppy: lr
F1 Generation:
Ll Rr (long-finned red guppy): This genotype represents the offspring that have long fins and a red color. They inherit one dominant allele for fin length (L) and one dominant allele for color (R) from their parents.
Ll Rr (long-finned green guppy): This genotype represents the offspring that have long fins and a green color. They inherit one dominant allele for fin length (L) from their long-finned parent and one recessive allele for color (r) from their short-finned green parent.
ll Rr (short-finned red guppy): This genotype represents the offspring that have short fins and a red color. They inherit one recessive allele for fin length (l) from their short-finned parent and one dominant allele for color (R) from their long-finned red parent.
ll Rr (short-finned green guppy): This genotype represents the offspring that have short fins and a green color. They inherit one recessive allele for both genes (l and r) from their parents.
Therefore, the F1 generation will consist of four different genotypes and four different phenotypes: long-finned red, long-finned green, short-finned red, and short-finned green guppies.