Question 1

Some evolutionary biologists argue that, overall, regulatory mutations are more likely to result in adaptation than changes in the protein-coding sequence of genes. Considering the logic underlying their argument, in which case below would this expectation not apply to a particular gene involved in adaptation?
A) The gene is involved in multiple functions.
B) The gene is involved in only one function.
C) The gene is expressed in different tissues.
D) The protein encoded by the gene performs an important function.

Accepted Answer

Regulatory mutations allow for changes in when, where, and how much a gene is expressed without altering the protein's function directly. This flexibility is particularly advantageous for genes involved in multiple functions (pleiotropy) or expressed in different tissues, as it allows for fine-tuning of gene expression in complex ways. However, for a gene involved in only one function (choice B), changes in the protein-coding sequence might be equally or more likely to result in adaptation because the specificity and efficiency of the protein's function could be directly optimized without unintended effects on other functions or tissues.

Question 2

Is the fly eye homologous to the mouse eye, or is it convergent?
A) homologous because of developmental genes that regulate the complex eye are
B) convergent because the fly eye is a compound eye and the mouse eye is a camera eye
C) both, depending on the level of development examined
D) neither; the two types of eyes cannot be compared

Accepted Answer

The fly eye and the mouse eye are considered both homologous and convergent depending on the level of development examined. At the genetic level, they share homologous developmental genes that regulate eye formation, indicating a common evolutionary origin. However, the structural and functional differences between the compound eye of the fly and the camera eye of the mouse are the result of convergent evolution, where similar environmental pressures lead to the development of similar traits independently.

Question 3

Which of the following statements is accurate regarding antagonistic pleiotropy?
A) The net fitness effect of an allele experiencing antagonistic pleiotropy may depend on the environment.
B) Alleles experiencing antagonistic pleiotropy should always be strongly selected against.
C) Antagonistic pleiotropy results when a trait is influenced by more than one gene.
D) none of the above

Accepted Answer

Antagonistic pleiotropy occurs when a single gene has multiple effects, some beneficial and some detrimental, on an organism's fitness. The net fitness effect of such an allele can indeed depend on the environment, as different environments may alter the balance between the beneficial and detrimental effects.

Question 4

The populations of the ray-finned teleost fish, Astyanax, that repeatedly colonized underground Mexican caves and evolved the same suite of derived traits in cave after cave is an example of
A) deep homology.
B) parallel evolution.
C) convergent evolution.
D) genetic drift.

Accepted Answer

Parallel evolution occurs when similar traits evolve independently in related species, often due to similar environmental pressures, as seen in the Astyanax fish repeatedly evolving similar traits in different caves.

Question 5

Placental mammals differ from marsupial mammals in that
A) they carry a developing fetus in a uterus.
B) they give birth to live young.
C) they lay eggs.
D) a and b

Accepted Answer

The answer of Placental mammals differ from marsupial mammals in...

Question 6

In Lenski's experiments, the key to evolution of citrate feeding in
E.coli was the accidental duplication of the citT ______ together with the rnk _____.
A) gene; promotor
B) gene; gene
C) promotor; promotor
D) promotor; gene

Accepted Answer

The key to the evolution of citrate feeding in E. coli in Lenski's experiments was the accidental duplication of the citT gene together with the rnk promotor. This duplication allowed for the expression of the citT gene in an environment where it normally would not be, enabling the bacteria to metabolize citrate under aerobic conditions.

Question 7

What does the following phylogeny suggest? 
A) The bilaterian ancestor likely had a nervous system arranged like cnidarians.
B) The bilaterian ancestor may have had a diffuse net of nerves.
C) The evolution of a single nerve cord occurred in the common ancestor of all animals.
D) a and b
E) a, b, and c

Accepted Answer

The answer of What does the following phylogeny suggest? 
A)...

Question 8

Which of the following is true of the complex eye?
A) It is an example of convergent evolution because of the borrowed crystallin genes that evolved independently.
B) It is an example of common ancestry because the development of all complex eyes in bilaterians is controlled by the same gene, Pax-6.
C) It is an example of deep homology because its growth and development in different lineages result from underlying genetic mechanisms that are inherited from a common ancestor.
D) a and b
E) a, b, and c

Accepted Answer

The complex eye exemplifies convergent evolution due to independently evolved crystallin genes, common ancestry through the Pax-6 gene controlling eye development across bilaterians, and deep homology because its development across different lineages is governed by genetic mechanisms inherited from a common ancestor.

Question 9

What does the following phylogeny of animals suggest? 
A) Dorsal-ventral patterning and a single nerve cord may have evolved in three independent lineages.
B) The common ancestor of invertebrates had a single nerve cord.
C) Arthropods have a unique dorsal-ventral pattern.
D) a and b
E) none of the above

Accepted Answer

The answer of What does the following phylogeny of animals...

Question 10

Why might Darwin disagree that bat wings and fly legs represent a homology?
A) because of the lack of genetic knowledge during his time
B) because flies are not vertebrates
C) because he could only recognize homology in the anatomy that he could see with the naked eye
D) all of the above

Accepted Answer

Darwin might disagree because he lacked genetic knowledge, flies are not vertebrates, and he could only recognize visible anatomical homologies.

Question 11

Gene duplication
A) results in genes that are paralogs.
B) leads to functional redundancy.
C) can result in one of the copies gaining a new function.
D) all of the above

Accepted Answer

Gene duplication can result in paralogs (genes related by duplication within a genome), often leads to functional redundancy (both copies initially perform the same function), and can allow one of the copies to gain a new function through mutations, a process known as neofunctionalization.

Question 12

The Engrailed (En) gene is an example of a(n)
A) paralog; it is crucial for defining the posterior portion of the limb bud in mice and for defining the leg disc in flies.
B) ortholog; it is crucial for defining the posterior portion of the limb bud in mice and for defining the leg disc in flies.
C) paralog; it is a homologous gene produced by gene duplication within the fly limb development pathway.
D) ortholog; it is a homologous gene produced by gene duplication within the fly limb development pathway.

Accepted Answer

Orthologs are genes in different species that evolved from a common ancestral gene by speciation and retain the same function. The Engrailed (En) gene's role in limb and leg disc development in both mice and flies illustrates this evolutionary conservation, making it an example of an ortholog.

Question 13

Snakes evolved about ____ million years ago, and their closest living relatives include ____.
A) 60; iguanas and monitor lizards
B) 0.1; iguanas and whiptail lizards
C) 150; iguanas and monitor lizards
D) 300; iguanas and crocodiles

Accepted Answer

Snakes evolved about 60 million years ago, and their closest living relatives include iguanas and monitor lizards.

Question 14

Which is the likely order of evolution of snake venom?
 I. diversification of venom genes
II. duplication of defensin gene
III. single copy of defensin gene
IV. gene recruitment in venom gland
A) III - II - IV - I
B) III - II - I - IV
C) IV - II - III - I
D) IV - I - III - II

Accepted Answer

The likely order of evolution of snake venom starts with a single copy of the defensin gene (III), followed by duplication of this gene (II), then the recruitment of these genes in the venom gland (IV), and finally the diversification of venom genes (I). This sequence suggests an initial genetic simplicity evolving towards complexity and specialization in venom production.

Question 15

What evidence suggests that c-opsins were present in the common ancestor of all living vertebrates?
A) All vertebrates carry c-opsin.
B) C-opsins have the same basic molecular shape in all vertebrates.
C) C-opsins have the same basic functional pathway in all vertebrates.
D) all of the above
E) none of the above

Accepted Answer

All of the options provided (A, B, C) suggest that c-opsins were present in the common ancestor of all living vertebrates. This is because the presence of c-opsins across all vertebrates, their consistent molecular shape, and their shared functional pathway across different species indicate a common ancestral origin.

Question 16

How does the development of a mouse leg differ from the development of a fly leg?
A) In a mouse leg, the proximal structures develop first.
B) In a mouse leg, the gene Hh controls development.
C) In a fly leg, the proximal segments develop first.
D) In a fly leg, the gene Shh controls development.

Accepted Answer

In a mouse leg, the proximal structures develop first, whereas in a fly leg, the distal structures develop first. The gene Shh (Sonic hedgehog) is involved in mouse limb development, while Hh (Hedgehog) is involved in fly limb development.

Question 17

Which of the following represent(s) homologies?
A) the forelimb structure of vertebrate wings, hands, and flippers
B) the limb structure of bilaterians
C) Hox genes in mice and flies
D) a and b
E) a and c

Accepted Answer

Homologies refer to traits inherited by two different organisms from a common ancestor. The forelimb structures of vertebrates (wings, hands, flippers) and Hox genes in mice and flies are examples of homologous structures and genes, respectively, indicating a common evolutionary origin.

Question 18

How does bat wing development differ from other tetrapod limbs?
A) The humerus forms first, followed by more distal structures.
B) The digits form first, followed by more proximal structures.
C) Increased expression of Bmp2 drives more cell division in developing digits.
D) Bat wing development does not differ from other tetrapod limbs; there is simple a gene that codes for longer digits.

Accepted Answer

Increased expression of Bmp2 in bats leads to more cell division in the developing digits, contributing to the elongation of the digits, which is a key difference in bat wing development compared to other tetrapod limbs.

Question 19

If you examine the phylogeny of animals, you would see that
A) eyes are not present in the common ancestor of all animals.
B) sponges and placozoans have no eyes.
C) eyes are found only within the eumetazoans.
D) all of the above
E) none of the above

Accepted Answer

The phylogeny of animals indicates that the common ancestor of all animals likely did not have eyes, as eyes are complex structures that evolved later in specific lineages. Sponges and placozoans, which are among the most basal groups of animals, indeed do not have eyes, supporting the idea that eyes are a more derived feature. Eyes are found within the eumetazoans, a group that includes all animals except sponges, placozoans, and a few other early-diverging lineages, indicating that the evolution of eyes occurred after the divergence of these basal groups.

Question 20

Which of the following statements accurately describes Hox genes?
A) They code for traits such as legs or wings in the developing embryo.
B) Their expression gives positional information to other genes.
C) They are transcription factors.
D) a and b
E) b and c

Accepted Answer

Hox genes provide positional information in the developing embryo, guiding the formation of structures in specific locations, and they function as transcription factors, regulating the activity of other genes.

Quiz 9: From Genes to Traits: the Evolution of Genetic Networks and Development

Is the fly eye homologous to the mouse eye, or is it convergent?

Which of the following statements is accurate regarding antagonistic pleiotropy?

The populations of the ray-finned teleost fish, Astyanax, that repeatedly colonized underground Mexican caves and evolved the same suite of derived traits in cave after cave is an example of

Placental mammals differ from marsupial mammals in that

In Lenski's experiments, the key to evolution of citrate feeding in E.coli was the accidental duplication of the citT __ together with the rnk _.

What does the following phylogeny suggest?

Which of the following is true of the complex eye?

What does the following phylogeny of animals suggest?

Why might Darwin disagree that bat wings and fly legs represent a homology?

Gene duplication

The Engrailed (En) gene is an example of a(n)

Snakes evolved about million years ago, and their closest living relatives include .

Which is the likely order of evolution of snake venom? I. diversification of venom genes II. duplication of defensin gene III. single copy of defensin gene IV. gene recruitment in venom gland

What evidence suggests that c-opsins were present in the common ancestor of all living vertebrates?

How does the development of a mouse leg differ from the development of a fly leg?

Which of the following represent(s) homologies?

How does bat wing development differ from other tetrapod limbs?

If you examine the phylogeny of animals, you would see that

Which of the following statements accurately describes Hox genes?