Question 1
Multiple choiceHard1 markResearchers recorded responses to courtship displays between and within two species, then recorded the outcomes of resulting matings. Evolution is a change in heritable characteristics of a population. Which interpretation is supported?
| Pairing | Courtship displays accepted (%) | Matings producing viable offspring (%) | Viable offspring that were fertile (%) |
|---|---|---|---|
| P × P | 84 | 92 | 96 |
| Q × Q | 81 | 90 | 95 |
| P × Q | 8 | 88 | 0 |
Show answer and explanation
Answer: C. Courtship displays were accepted less often between species than within either species, indicating a behavioural barrier to mating. Although some interspecific matings produced viable offspring, none of the viable hybrids were fertile, so they could not pass alleles to later generations. The results indicate barriers to allele flow but do not show a change in heritable characteristics of a population over time.
A: Confuses viability with fertility; the hybrids were viable but could not reproduce.
B: Reverses the barrier stages: courtship affects mating before fertilization, while sterility occurs in hybrids.
D: Treats a difference between pairings as evidence of heritable change over time; the data do not establish that change.
Remember: Viable offspring can still be sterile and unable to transmit alleles to another generation.