Which statement best describes iteroparous and semelparous reproductive strategies?

• A. Iteroparous species reproduce only once and then die; semelparous reproduce multiple times.
• B. Iteroparous species reproduce multiple times in life; semelparous reproduce once and then die.
• C. Both reproduce every year; differ in number of offspring.
• D. Semelparous species never reproduce.

Answer: (B)

Reproductive strategy is about how often an organism reproduces during its life. Iteroparous species reproduce more than once across their lifespan, often across multiple seasons or years, with the possibility of surviving between reproductive events to reproduce again. Semelparous species invest most of their reproductive energy into one big breeding effort and then typically die afterward; this single event can yield a very large number of offspring. That’s why this option—with iteroparous species reproducing multiple times in life and semelparous reproducing once and then dying—is the best match. Examples: humans and many mammals are iteroparous, while Pacific salmon and some insects are semelparous. The other ideas don’t fit the defining pattern: reproducing only once and then dying describes semelparity, not iteroparity; claiming both reproduce every year ignores the distinct single-event strategy of semelparity; and saying semelparous never reproduce is false because their key feature is a single reproductive event before death.