Question
Inflorescences (clusters of flowers) make up a lower proportion of plant biomass in perennial species (reproduce every year) as compared with annual species (reproduce only once). Explain this observation with reasoning that is consistent with evolutionary theory.
▶️Answer/Explanation
Ans:
Natural selection favors minimizing reproductive effort.
Reproductive effort is the proportion of energy and other resources
that an organism allocates to reproduction as opposed to its own
growth and maintenance. Reproductive effort is greater per year in annual
plant species because they have only one opportunity to reproduce. Annual
plants reproduce once and then die.
Perennial plants will reproduce many times over the course of a
lifetime, so each reproductive effort is typically lower than the one
reproductive effort made by the annual species. The cumulative cost of
reproduction in perennial plants increases with time and can exceed that of
an annual species over its lifetime. However, the perennial plant can
continue to acquire resources over its life span, whereas annual species
will typically have less time to obtain the energy to devote to
reproduction.