learning objectives 7 Flashcards
What is the Biological Species Concept?
The Biological Species Concept defines a species as a group whose members have the potential to interbreed in nature and produce viable, fertile offspring.
What unites members of a biological species?
Gene flow between populations of that species.
What keeps species apart?
Reproductive isolation, which creates barriers in gene flow
What is speciation?
The divergence of a lineage into multiple species.
Name two alternative species concepts to the Biological Species Concept.
Morphological Species Concept and Ecological Species Concept.
When is the Morphological Species Concept used?
It is used when species are defined by morphological traits alone, often by paleontologists for fossils or when reproductive biology is not available.
When is the Ecological Species Concept used?
It defines species by the ecological niches they occupy, often overlapping with the Morphological Species Concept.
What is habitat isolation? Give an example.
Habitat isolation occurs when species live in the same area but occupy different microhabitats, preventing mating. Example: Some fish species in deeper water may not mate with fish in higher water.
What is temporal isolation? Give an example.
Temporal isolation occurs when mating happens at different times of the year. Example: Two species of lotus never interbreed because they emerge at different times.
What is behavioral isolation? Give an example.
Behavioral isolation occurs when differences in courtship behavior prevent mating. Example: Two species of lacewings only respond to the mating song of their own species.
What is mechanical isolation?
Mechanical isolation happens when two individuals cannot physically breed due to incompatible reproductive structures.
What is gametic isolation?
Gametic isolation occurs when gametes are not compatible, preventing fertilization.
What are postzygotic barriers? Give an example.
Postzygotic barriers occur after mating, where offspring are less viable or less fertile than their parents. Example: A mule produced by a horse and a donkey.
How does gene flow relate to the formation of new species?
When gene flow stops between populations, they begin to diverge due to local adaptation, leading to the formation of new species.
What is allopatric speciation?
Allopatric speciation occurs when a population is geographically separated, leading to reproductive isolation and divergence into new species.
