Temporal Isolation: Example, Definition & Quiz
What prevents species that are closely related from mating with each other? Temporal isolation is an evolutionary mechanism that keeps individuals of different species from interbreeding, even if they live in the same environment.
It makes sense that a frog cannot mate with a bear or a cow, but sometimes even very closely related species - like two different species of frog - will not reproduce and have offspring. Reproductive barriers are biological features of organisms that prevent species from interbreeding.
There are two types of reproductive barriers: prezygotic barriers and postzygotic barriers. Prezygotic barriers are those that prevent mating between different species. Postzygotic barriers are those that reduce the likelihood that an offspring will survive after mating has occurred, but before the offspring is actually born.
One prezygotic reproductive barrier is temporal isolation. Temporal isolation means 'isolated in time', so this is a mechanism that prevents species from mating because they breed at different times. These differences can be time of day, season, or even different years. Both plants and animals may exhibit temporal isolation, even if the species are closely related and live in the same habitat.
One example of seasonal temporal isolation is the American toad and Fowler's toad. These are closely related species, but the American toad mates in the early part of summer, while the Fowler's toad mates later in the season.
Even though they live in the same geographic area, the eastern spotted skunk and western spotted skunk do not mate because their breeding seasons occur at different times of year. The breeding season for the eastern spotted skunk is in the late winter, while the breeding season for the western spotted skunk is in the fall.
There are different species of cicada that are prevented from mating by temporal isolation. Some cicadas breed only every seven years, while others breed every thirteen years. Unless these breeding years align, the species will not breed with each other.
Temporal isolation can also occur even if the two species do breed at the same time of year. For example, if two species of bird do not feed at the same time of day, they are less likely to interact and therefore not likely to mate with each other.
Flowering plants may be temporally isolated if their flowers do not open at the same time of day. When this occurs, pollen cannot be transferred between the two different plants, so there cannot be fertilization.
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