Speciation Overview and Concepts

When populations of the same species become genetically isolated by lack of gene flow and then diverge from each other due to selection, genetic drift, or mutation.

Reproductively isolated from each other, if they have distinct morphological characteristics, or if they form independent branches on the phylogenetic tree.

Occupy different geographic areas, use different habitats or resources within the same area, or if one population is polyploid and cannot breed with the other.

<p>They may fuse, continue to diverge, stay partially differentiated, or have offspring that form a new species.</p> Signup and view all the answers

<p>A splitting event that creates two or more distinct species from a single ancestral group.</p> Signup and view all the answers

<p>Species</p> Signup and view all the answers

<p>Identifying species based on reproductive isolation where no gene flow occurs between populations.</p> Signup and view all the answers

<p>Prevents individuals of different species from mating; reproductive isolation occurs before mating can.</p> Signup and view all the answers

<p>Offspring of matings do not survive or reproduce; mating does occur but produces low fitness.</p> Signup and view all the answers

<p>Cannot evaluate fossils or asexual organisms; difficult to apply to closely related populations who do not overlap geographically.</p> Signup and view all the answers

<p>Independent lineages identified by different shapes, sizes, or other features.</p> Signup and view all the answers

<p>Features to distinguish species are subjective.</p> Signup and view all the answers

<p>Independent lineages based on reconstructing evolutionary history of populations.</p> Signup and view all the answers

<p>A clade consisting of an ancestral population and all of its descendants.</p> Signup and view all the answers

<p>Each tip is a phylogenetic species.</p> Signup and view all the answers

<p>Can be applied to any populations; populations are distinct enough to be monophyletic if they are isolated from gene flow.</p> Signup and view all the answers

<p>Carefully estimated phylogenies are available only for a tiny subset of populations on the tree of life.</p> Signup and view all the answers

<p>Populations that live in discrete geographic areas with distinguishing features but are not considered distinct enough to be called separate species.</p> Signup and view all the answers

<p>By dispersal and vicariance.</p> Signup and view all the answers

<p>Physical splitting of a population.</p> Signup and view all the answers

<p>Physical isolation by dispersal and vicariance.</p> Signup and view all the answers

<p>Populations that live in different areas.</p> Signup and view all the answers

<p>Study of how species and populations are distributed geographically.</p> Signup and view all the answers

<p>Most likely different due to founder effects and natural selection may extend the rapid divergence that begins with genetic drift.</p> Signup and view all the answers

<p>Populations or species live close enough to one another to make interbreeding possible.</p> Signup and view all the answers

<p>Speciation that occurs even when gene flow is possible.</p> Signup and view all the answers

<p>Even though they are not physically isolated, they may be isolated by preferences for different habitats.</p> Signup and view all the answers

<p>A chromosomal alteration in which the organism possesses more than two complete chromosome sets.</p> Signup and view all the answers