Exam 22: Speciation

Hybrid organisms frequently die as embryos or at an early age, a phenomenon called hybrid breakdown.

When two organisms do not mate because they breed at different times of the year, they are exhibiting ____ reproductive isolation.

To answer questions about the genetic changes underlying speciation, scientists are now isolating and sequencing ____.

At least two host races of apple maggots have appeared within the past 150 years, suggesting they may be undergoing ____.

Which avenue of research is least likely to reveal whether asexual organisms form species?

Two plant species live in the same location and flower at the same time, but do not hybridize because they have unique pollinators. This is an example of ____.

Species that live in different habitats exhibit ____ reproductive isolation.

Darwin recognized that ____ had generated the amazing diversity of organisms on Earth.

A triploid plant is usually ____ because chromosomes cannot segregate properly during ____.

When allopatric populations reestablish contact upon elimination of a geographical barrier, ____ has occurred.

Today, evolutionary biologists view speciation as a ____, and instead study the ____ of speciation using classical and genomic approaches.

Many host races of the apple maggot have been identified; this is an example of allopatric speciation.

A plant with a very small tubular type of flower that cannot be pollinated by a large honeybee is exhibiting which prezygotic isolating mechanism?

Which scenario is an example of mechanical reproductive isolation?

A ____ mutation in snails can reverse the direction of shell coiling, which ____ mating.

When autopolyploid speciation occurs in a plant, a spontaneous doubling of chromosomes during meiosis leads to the production of ____ gametes. If the plant fertilizes itself, a ____ zygote will be produced.

With the biological species concept, the process of speciation is frequently defined as the evolution of ____ between populations.

Polyploid individuals arising from chromosome duplications within a single species are called ____.

An example of a prezygotic isolating mechanism is behavioral isolation.

Researchers hypothesize that the hybrid zone of Bullock's orioles and Baltimore orioles remains narrow because hybrids ____.