unit 2 practice test

Which of these best explains the loss of ventral spines in stickleback fish?

changes in the protein by Pitx1

Which of the following germ (embryonic tissues) layers becomes your skeleton and muscles?

mesoderm

What do animals ranging from corals to monkeys have in common?

presence of Hox genes

What information can be found in the human genome?

-carrier of disease -which chromosomes have which genes -all gene of a human

Based on the tree shown, which statement is false?

Acoelomate flatworms are more closely related to echinoderms than to annelids.

Which of these correctly describes phylogenetic relationships among birds, mammals, and reptiles

Birds share the closest common ancestor with dinosaurs.

Which two main clades branch from the most recent common ancestor of the eumetazoans?

Cnidaria and Bilateria

Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago?

DNA coding for rRNA changes relatively slowly.

Regarding genome size and density

Eukaryotic genomes are larger than prokaryotic genomes

Adaptive radiations can be direct consequences of three of the following four factors. Select the expression

Genetic drift

Humans are

Homo sapiens

Bones in penguin flipper and bones in bat wings is an example of what?

Homologous

Why do some stickleback populations lack pelvic spines?

In lakes where there are no predatory fish, there is no advantage to having pelvic spines.

How has gene duplication played a critical role in evolution?

It produces redundant copies of existing genes, which are then free to mutate and adopt new functions.

In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. Why is this the case?

Nonidentical genes produce different versions of globins during development.

Which term describes a steady state in which internal conditions of an organism are kept within narrow range without regard to the external conditions ?

Regulatory homeostasis

How do retrotransposons differ from other transposons?

Retrotransposons move via an RNA transcript, whereas other transposons do not.

Which of these is true about vertebrates?

The development of an amniotic egg and internal fertilization allowed vertebrates to reproduce away from water

What conclusion is apparent from the data in the table above?

The expansion in number of Hox genes throughout vertebrate evolution cannot be explained merely by three duplications of the ancestral vertebrate Hox cluster.

Paedomorphosis

The retention in an adult organism of the juvenile features of its evolutionary ancestors.

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of

a change in a developmental gene or in its regulation that altered the spatial organization of body parts

Which of the following could be considered the most recent common ancestor of living tetrapods?

a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates

Listed below are four adaptations of terrestrial vertebrates. Which is a characteristic only of truly terrestrial animals with no need to return to water at any stage of the life cycle?

amniotic eggs

homeotic genes

encode transcription factors that control the expression of genes responsible for specific anatomical structures

Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity?

exon shuffling

One of the characteristics unique to animals is

gastrulation

Unlike eutherians, both monotremes and marsupials _____.

have some embryonic development outside the uterus

Which of the following is the most inclusive term for an organism that obtains organic food material by eating other organisms or substances derived from them?

heterotroph

Which process occurred frequently in the early history of the three domains on Earth and makes determining phylogenetic relationships of that time difficult?

horizontal gene transfer

Which of the following is (are) unique to animals?

nervous system signal conduction and muscular movement

Which structure provides stiffness to the bodies of developing chordates?

notochord

Molecular clocks are based on the idea that _____

on average neutral mutations arise at a constant rate

Select the characteristics that define a chordate

post anal tail, pharyngeal slits, notochord

Most of the human genome is made up of

repeats of DNA sections (e.g., Alu).

Which of the following was probably the least important factor in bringing about Cambrian explosion?

the movement of animals onto land

Which two globin genes are most divergent from each other? What is the percent amino acid identity between them?

β and ζ, with 38% amino acid identity