1) Karl Ernst von Baer (17921876), a German naturalist, biologist, and embryolog
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Question
1) Karl Ernst von Baer (17921876), a German naturalist, biologist, and
embryologist, rejected both the scala naturae and the MeckelSerres law. Instead, von Baers law states that the:
A) embryos display characteristics of embryos from species that preceded them on the scala naturae.
B) general characteristics of embryos in closely related species develop before specific characteristics, and embryos of higher taxa do not resemble the adult form of ancestral lower-taxa species.
C) developmental stages of an organism progress through all the animal species that came before it on the scala naturae.
D) embryos of organisms progress through the adult stages of species that preceded them.
2) Ernst Haeckel (18341919), a German biologist and naturalist, disagreed with
von Baer and further expanded on the MeckelSerres law with his biogenetic law. What does the biogenic law claim?
A)The evolutionarily novel traits tend to appear late in development and are good diagnostics for separating closely related species.
B)The traits that appear early on in development are extremely resistant to evolutionary change, and hence they are very similar across many taxa.
C) The developmental progress of an organism (its ontogeny) recapitulates its evolutionary history (its phylogeny).
D) all of the above
3) Which of the following are/is considered a type of heterochrony (changes in the rate and timing of development)?
A) hypermorphosis
B) acceleration
C) neoteny
D) all of the above
4) When a reproductive trait appears earlier in development or when some somatic traits of an adult are retarded, we could define this type of development as:
A) recapitulation.
B)acceleration.
C) paedomorphosis.
D) hypermorphosis.
5)Heterochrony is well studied in amphibians. One of the famous examples is in a species of salamanders (Mexican axolotl), where reproductively mature individuals still live in the water and have external gills and flat tails, as in the salamander embryos. This phenomenon is best defined as:
A) neoteny.
B) progenesis.
C) acceleration.
D)hypermorphosis.
6) Thyroid hormone (TH) has been identified as one of the factors promoting phenotype development in the Mexican salamander, or axolotl. All of the following statements regarding the impact of TH are true except:
A)Axolotls maturing in water with high concentration of T4 metamorphose into a terrestrial form.
B) Most salamander species produce a burst of TH when they move from the water to the land.
C) Adding thyroid hormone (T4) to the water in which axolotl individuals were reared causes them to remain in a larval stage.
D) A genome-wide scan of both the axolotl and its sister species found a large reduction in the number of mRNA genes that regulate the production of TH.
7) When we say that a cell is totipotent, we refer to a cell that:
A) has undergone a specific developmental pathway.
B) could differentiate into any of the cell types that makes up the adult organism.
C) could differentiate into only one type of cells, yet producing a number of different categories (such as different categories of blood cells).
D) all of the above
8) Define homeotic genes.
A) Homeotic genes encode proteins that control cellular environment in a differentiated cell tissue.
B) Homeotic genes are DNA sequences that turn off, but not on, the expression of other genes and are controlled by master-switch genes.
C) Homeotic genes are master-switch genes that control other genes in a set sequence and thereby affect cell size, shape, division, and the positioning of the cells within the organism.
D) all of the above
9) In the early 1980s, studies in fruit flies led to discovery of the master-switch genes involved in animal development. Which of these genes are essential for the development of different body segments of fruit flies?
A) MAD-box genes
B) Hox genes
C) segmental genes
D) none of the above
10) One of the first studied Hox gene mutations in Drosophila was a mutation in the Antennapedia (Ant) gene, which controls leg formation. This mutation is abbreviated as Antp. What is the phenotypic effect of this mutation?
A) Antennae are replaced by legs.
B) Antennae are replaced by wings.
C) Abdominal parts develop in the anterior.
D) Four pairs of legs in the thoracic region.
11) What would be an appropriate evolutionary explanation of the fact that the ordering of some homeotic genes (e.g., Hox genes) on vertebrate chromosomes parallels the ordering of homeotic genes on fruit fly chromosomes?
A) Homeotic genes show that insects and vertebrates are closer relatives than the traditional classification system indicates.
B) Homeotic genes display ancient homologies.
C) Homeotic genes of different animal lineages might be ordered in a similar fashion, yet their sequences are completely different.
D) The similarity is a coincidence, not documented in other invertebrates and largely a result of random mutations.
12) Which of the following statements is true about Hox genes experiments?
A) Homeobox regions of the Hox genes allow one species transcription factor to function in the other species.
B) When the mouse Hox-2.2 gene is experimentally inserted into the fruit fly genome and expressed in the head of developing fruit flies, adults produce legs in place of antennae.
C) When a Hox gene product from an appropriate chromosomal region in chickens was inserted into a fruit fly embryo, it resulted in normal regulation of the fruit fly development.
D) all of the above
13) Deep homology of homeotic genes is also seen in plants. For example, the MADS-box genes have been used to work out phylogenetic relationships within flowering species of plants. What was also documented in these studies across many plant lineages?
A) The MADS-box genes play a role in flower development, but they dont have any effect on nonflowering plant species, such as gymnosperms.
B) The MADS-box genes are also instrumental in nonflowering plant species, where they are involved in developmental pathways in leaf and root systems.
C) There is almost no similarity among the flowering and nonflowering plants, in the structure of MADS-box genes that are involved in the early developmental pathways.
D) none of the above
14) Define a regulatory enhancer of a gene.
A) The state of chromatin in the surrounding areas is the main enhancer of a gene.
B) target proteins for degradation and thus stop the expression of the unwanted genes.
C) The regulatory enhancer is a section of DNA that lies outside of that gene but is involved in regulating the timing and level of that genes expression.
D) none of the above
15) If a gene is affected by many regulatory enhancers, what would be an important evolutionary implication?
A) The enhancers can increase morphological variation and hence the amount of variation that natural selection has to act on.
B) A single gene can have numerous regulatory enhancers associated with it, but these regulators can produce only small variations in gene expression.
C) There is no current experimental data that would indicate evolution in the regulatory enhancers.
D) The primary control point at which gene expression is regulated is initiation of translation, so transcription enhancers do not play a significant role.
QUESTION 18
16) In some species of fruit flies, males have black spots on the edge of their wings, which they use for visual displays during courtship dances with females, while in other species, these spots are completely absent. A gene called yellow plays a role in the development of these visual features in all of the species. The key to the differences in the amount and spatial distribution of the yellow protein is due to?
A)Different gene sequences are recognized as the yellow gene in the different fruit fly species.
B) the effects of regulatory enhancers on the yellow gene
C) The fact that in fruit fly species without spots there is a regulatory enhancer that causes the yellow gene to express the yellow protein at high levels all over the wing.
D) all of the above
QUESTION 19
Douc langurs are primates that have a diet of leaves instead of insects and fruit. In order to digest such food, these langurs use symbiotic bacteria in their gut and digest some of them using an enzyme associated with a gene known as RNASE. Gene duplication and the subsequent divergence of this gene, seems to be the genetic basis for its evolution. We could say that this is an example of:
A) increasing production of ribosomal RNA and histones.
b) subfunctionalization.
c) neofunctionalization.
d) all of the above
Explanation / Answer
.
B) general characteristics of embryos in closely related species develop before specific characteristics, and embryos of higher taxa do not resemble the adult form of ancestral lower-taxa species.
2) Ernst Haeckel (18341919), a German biologist and naturalist, disagreed with
von Baer and further expanded on the MeckelSerres law with his biogenetic law. What does the biogenic law claim?
C) The developmental progress of an organism (its ontogeny) recapitulates its evolutionary history (its phylogeny).
3) Which of the following are/is considered a type of heterochrony (changes in the rate and timing of development)?
D) all of the above
Explanation: Species with faster growth shows acceleration and species with slower growth shows neoteny. Hypermorphosis is exhibited by species whose end of development is delayed. Hypermorphosis, neoteny and acceleration are three dimensions of heterochony.
4) When a reproductive trait appears earlier in development or when some somatic traits of an adult are retarded, we could define this type of development as:
C) paedomorphosis.
Paedomorphosis involves acceleration of sexual maturation relative to the development of the rest of the body or retardation of bodily development.
5)Heterochrony is well studied in amphibians. One of the famous examples is in a species of salamanders (Mexican axolotl), where reproductively mature individuals still live in the water and have external gills and flat tails, as in the salamander embryos. This phenomenon is best defined as:
A) neoteny.
Retention of larval traits in salamanders and sexual development occurs faster.
7) When we say that a cell is totipotent, we refer to a cell that:
B) could differentiate into any of the cell types that makes up the adult organism.
Totipotency is the ability or capacity of cells to differentiate or show the property of differentiation which ultimately gives rise to different cell types.
8) Define homeotic genes.
C) Homeotic genes are master-switch genes that control other genes in a set sequence and thereby affect cell size, shape, division, and the positioning of the cells within the organism.
Homeotic genes control the pattern of development in an organism through exercising control over other genes or with the help of transcription factors.
9) In the early 1980s, studies in fruit flies led to discovery of the master-switch genes involved in animal development. Which of these genes are essential for the development of different body segments of fruit flies?
B) Hox genes
Hox genes produce Hox proteins which control the type of segmental structures in fruit flies
10) One of the first studied Hox gene mutations in Drosophila was a mutation in the Antennapedia (Ant) gene, which controls leg formation. This mutation is abbreviated as Antp. What is the phenotypic effect of this mutation?
A) Antennae are replaced by legs.
Gain of function mutation in Antennapedia (Ant) gene results in the conversion of antennae into legs
13) Deep homology of homeotic genes is also seen in plants. For example, the MADS-box genes have been used to work out phylogenetic relationships within flowering species of plants. What was also documented in these studies across many plant lineages?
B) The MADS-box genes are also instrumental in nonflowering plant species, where they are involved in developmental pathways in leaf and root systems.
MADS box genes in plants are involved in gametophyte formation as well as other development processes like in roots and leaf of the plant
14) Define a regulatory enhancer of a gene.
C) The regulatory enhancer is a section of DNA that lies outside of that gene but is involved in regulating the timing and level of that gene’s expression.
Enhancer’s are region in the DNA that is several base pairs away from the target gene and it controls the function of the target gene. These proteins are also called as transcription factors
15) If a gene is affected by many regulatory enhancers, what would be an important evolutionary implication?
.
B) A single gene can have numerous regulatory enhancers associated with it, but these regulators can produce only small variations in gene expression.
QUESTION 18
16) In some species of fruit flies, males have black spots on the edge of their wings, which they use for visual displays during courtship dances with females, while in other species, these spots are completely absent. A gene called yellow plays a role in the development of these visual features in all of the species. The key to the differences in the amount and spatial distribution of the yellow protein is due to?
C) The fact that in fruit fly species without spots there is a regulatory enhancer that causes the yellow gene to express the yellow protein at high levels all over the wing.
QUESTION 19
Douc langurs are primates that have a diet of leaves instead of insects and fruit. In order to digest such food, these langurs use symbiotic bacteria in their gut and digest some of them using an enzyme associated with a gene known as RNASE. Gene duplication and the subsequent divergence of this gene, seems to be the genetic basis for its evolution. We could say that this is an example of:
c) neofunctionalization.
Neofunctionaliztion occurs when one copy of a gene undergoes duplication and takes on a totally new function as a result of which new adaptations are formed.
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