Exam 19: Development and Evolution

South American anteaters have no teeth and a long sticky tongue; they rip open anthills and termite mounds and capture insects with their tongues.An Australian marsupial known as the numbat (Myrmecobius fasciatus)is not closely related to anteaters,but it too has highly reduced teeth and a long sticky tongue,and it feeds by ripping open termite burrows and lapping the insects up.Such similarities between species that are not inherited from a common ancestor are known as ________.

In early human embryos,the gene HoxB7 is involved in patterning the central nervous system.In later embryos,HoxB7 plays a critical role in growth and development of the kidney.These different functions of the same gene at different times and places are an example of ________.

The discoverer of "homeotic mutations," who also resisted the growing "modern synthesis" model of evolution,was ________.

Genes of both the ANT-C and BX-C clusters encode proteins that all include a common sequence of amino acids that interact with DNA,known as the ________.

Despite a great deal of variation across the animal kingdom,Hox genes tend to appear along a chromosome or chromosomes in the same order that they are expressed in along the anteroposterior axis of an embryo.This pattern of Hox gene expression is called the ________.[four words]

Libbie Hyman's comprehensive study of invertebrates,beginning in the 1940s,was noteworthy for being one of the few major works at the time to ________.

A ________ is one who believes that major evolutionary change happens,or can happen,by large "jumps" or bursts,such as mutations with large effects.

Mutations of ________ [two words] in fruit flies can cause appendages to appear in the wrong places,such as legs growing in place of antennae.

The simplest hypothesis for the original function of Hox genes is that the common ancestor of bilateral animals had Hox genes that were ________.

All of the following factors can cause rapid evolutionary "jumps" except ________.

At the end of the chapter,the text points out that almost all our knowledge of evo-devo is based on plants and animals; we know little about other complex multicellular organisms that undergo development.Consider a mushroom,a member of the Kingdom Fungi.Based on what you know of its structure and mode of growth,would you predict that it would have orthologous genes to the Hox genes of animals? Explain why or why not.

The hindwing eyespots of the butterfly Bicyclus anyana responded to artificial selection for increased gold color in both or increased black color in both,but artificial selection could not produce increased gold in one spot and increased black in the other.This is an example of ________.

Evolutionary shifts in the relative rates and timing of developmental events are known as ________.

The simplest hypothesis for the original function of Hox genes is that they were expressed in the ________ [two words] in early animals.

The embryonic nervous systems of peanut worms (Sipuncula)and spoon worms (Echiura)show that these worms ________.

When selection increases one feature of an organism at the expense of another,we speak of an evolutionary ________.

According to a database kept by the HUGO Gene Nomenclature Committee,there are currently six genes in the human genome for different variants of the protein collagen IV.Assuming that all these genes are derived from an ancestral gene,the most precise term for these genes would be ________.

The eighteenth-century French scientist Étienne Geoffroy Saint-Hilaire argued for a far-reaching concept of what we would now call homology.For example,he argued that the vertebrae and ribs of vertebrates are fundamentally the same structures,built on the same plan,as the segmented exoskeleton and legs of insects and other arthropods.Insects,according to Geoffroy Saint-Hilaire,quite literally live inside their vertebrae and walk on their ribs.His idea is not really true in the sense that he conceived it―and yet,in the light of discoveries about Hox genes and developmental regulation,some modern evolutionary biologists have had good things to say about Geoffroy Saint-Hilaire's work.(See "Brotherhood by Inversion" in Stephen Jay Gould's book Leonardo's Mountain of Clams and the Diet of Worms,for example.)Explain why a modern "evo-devo" specialist might find Geoffroy Saint-Hilaire's ideas worth revisiting in the light of current knowledge.

Which of the following is a good example of two genes that are orthologous?

The concept of developmental constraint may be defined as ________.