Following their respective breeding seasons, several species of hummingbirds occ
ID: 96371 • Letter: F
Question
Following their respective breeding seasons, several species of hummingbirds occur at the same locations in North America and several hummingbird flowers bloom simultaneously in these habitats. These flowers seem to have converged to a common morphology and color. Birds are most visually sensitive to the color red. Hummingbird flowers are pollinated by hummingbirds. Which of the following features of these flowers would indicate they have coevolved with hummingbirds? (Check all that apply)
Check All That Apply long tubular flowers flowers are colored violet and blue blooming time of the flowers coincides with the arrival of the hummingbirds flowers produce a high volume of nectar and sugar flowers are low to the groundExplanation / Answer
Coevolution is the evolution of two or more species which affects each other, generally creating a mutualistic relationship between the species. These types of evolutionary interactions were discussed by Charles Darwin in his book On the Origin of Species (1859)
Hummingbirds and ornithophilous (bird-pollinated) flowers (in this case-humming bird flowers) show a mutualistic evolutionary relationship. The nectars of these flowers are best suited to the birds' diet, their color is favorable for the birds' vision and their tubular shape fits that of the birds' bills. Also, the blooming times of the flowers coincides with the breeding seasons of hummingbirds.
Flowers have converged to take advantage of similar birds. There is always a competition in flowers for pollination, and adaptation reduces the unfavorable effects of this competition. Because birds can fly during the severe and harsh unfavorable weather, they are considered to be better pollinator as compared to the insects which remain inactive during the harsh weather. Due to this reason, ornithophily (pollination by birds) is always preferred in isolated environments with very less number of insects or areas with plants which flower in the winter.
Bird-pollinated flowers usually have higher volumes of nectar and higher sugar production than those pollinated by insects, so as to meet the birds' high energy need as these hummingbirds are quite active. The different lengths and shapes of the corolla tubes of the flowers can determine the efficiency of extraction in hummingbird species in relation to differences in bill morphology. The tubular flowers influence a bird to move its bill in a particular way when searching the flower, especially when both the bill and corolla are curved; this also enables the plant to place pollen on a certain part of the bird's body which further opens the door for a variety of morphological co-adaptations. An important requirement for attraction is visibility of flowers to the birds. Birds have their highest sensitivity for the red end of the visual spectrum, so red is clearly visible to them. So, the following features, i.e.,
Long tubular flowers- which helps the hummingbird to put its bill
Red coloured flowers- that attracts the hummingbird (not given in the options)
the blooming times of the flowers coincides with the breeding seasons of hummingbirds
and flowers producing a high volume of nectar and sugar- that suites the hummingbird as this bird needs more energy
have allowed hummingbirds and hummingbird flowers to co evolve.
Note: The third option i.e., flowers produce a high volume of nectar and sugar also should be one of the feature for coevolution.
But I am unable to select and tick that