Question

For dispersal, type D into the box For vicariance, type V into the box A species of mussel from the Mediterranean Sea "hitched a ride" on the bottom of a large boat and traveled to the American Great Lakes. This expanded their range. The mussels in the Great Lakes are beginning to speciate and are reproductively isolated from their Mediterranean ancestors. Small, migratory songbirds usually traveled to Italy during the cold winter and back to Germany during the warm summer. As the climate became more mild, the birds no longer migrated. Some of the birds remained in Italy year- round, and others remained in Germany year-round. This led to speciation due to geographic separation in their ranges and the loss of migration. -Species of large, flightless birds are found on all the southern continents. It is believed that these birds evolved while Gondwana was still united. Following the break-up of Gondwana into islands, the birds speciated to meet the needs of the unique habitats on each continent. During the late Cretaceous, marsupials radiated and spread across all of Pangaea. When Pangaea broke into Laurasia and Gondwana, placental mammals became the dominant clade across Laurasia because they outcompeted most northern marsupials. However, on the isolated southern continent of Gondwana, the marsupials dominated. This pattern is still observed: Placental mammals are more common north of the Equator, and marsupials are m distributed south of the equator. ostly

Answer 1

vicariance and dispersal both are modes of allopatric speciation. However, major difference between them is barrier. In vicariance the species divided due to appearance of barrier and in dispersal barrier already exists. In other words, in dispersal, species leave and disperse to new area but in vicariance changes in habitat are responsible for the species distribution in 2 ranges.

A species of mussel from the Mediterranean Sea “hitched a ride" on the bottom of a large boat and traveled to the American Great Lakes. This expanded their range. The mussels in the Great Lakes are beginning to speciate and are reproductively isolated from their Mediterranean ancestors.

Answer 1: It is an example of dispersal.

Small, migratory songbirds usually traveled to Italy during the cold winter and back to Germany during the warm summer. As the climate became more mild. the birds no longer migrated. Some of the birds remained in Italy year- round, and others remained in Germany year-round. This led to speciation due to geographic separation in their ranges and the loss of migration.

Answer 2: It is an example of vicariance.

Species of large. flightless birds are found on all the southern continents. It is believed that these birds evolved while Gondwana was still united. Following the break-up of Gondwana into islands, the birds speciated to meet the needs of the unique habitats on each continent.

Answer 3: It is an example of dispersal because speciation occurs after barrier formation so barrier already exists.

During the late Cretaceous, marsupials radiated and spread across all of Pangaea. When Pangaea broke into Laurasia and Gondwana. placental mammals became the dominant clade across Laurasia because they outcompeted most northern marsupials. However, on the isolated southern continent of Gondwana, the marsupials dominated. This pattern is still observed: Placental mammals are more common north of the Equator, and marsupials are mostly distributed south of the equator.

Answer 4: It is an example of vicariance.