Exam 13: Speciation and Extinction

When the researchers crossed M.lewisii and M.cardinalis,the hybrids had which genotype?

Ernst Mayr defined a biological species as:

Postzygotic isolation barriers prevent:

Scientists have a very complete fossil record showing the evolution of horses over millions of years,with the legs becoming longer and the teeth larger as ancestors of the modern horse adapted from living in forest to grasslands.This is an example of ____.

The type of reproductive isolation in which offspring are infertile because their chromosomes cannot align correctly during meiosis because of a different number of chromosomes being inherited from the two parents is:

The speciation that occurred in the islands of the Greater Antilles (Cuba,Puerto Rico,Jamaica,and Hispaniola)with lizards called anoles is an example of adaptive radiation.

"Missing" transitional forms may not be present in the fossil record because of poor preservation of biological material and simply because scientists have not discovered all there is to discover.

The Caribbean islands are home to more than 150 species of anole lizards.Why would so many species evolve from a single common ancestor?

The larger the initial population size the less likely it will endure a major environmental change.

This experiment supports the hypothesis that a change in just one gene locus may have jump-started speciation in Mimulus.If so,this would be an example of:

A sterile mule is produced by mating a horse and a donkey.From this observation you could conclude:

The spatial arrangements that may help cause speciation are:

An evolutionary tree depicts species' relationships based on descent from shared ancestors.

A small angle for a branch point in an evolutionary tree indicates:

The rough periwinkle,Littorina saxatilis,is found on the coast of northern Spain.The snails farther up the shore are large with heavily ridged and banded shells,while those exposed to the waves farther down the shore are smaller with smooth and unbanded shells.This separation along the boundary of a habitat could lead to ____ speciation.

Today scientists can fill in gaps in defining species by DNA sequence analysis.

The process by which species cease to exist:

In Table 13.3,what can be concluded about the flower preferences of bumblebees?

The idea that evolution proceeds in small,incremental changes over many generations is:

A tetraploid (four sets of chromosomes)plant species would normally be ______________; whereas a plant species with three sets of chromosomes would normally be ______________.This is due to whether or not meiosis may be completed correctly.