Animal Classification

The recent reassessment of animal classification is primarily the result of:

Approximately how many animal phyla are currently recognized by scientists?

What is a unifying feature shared by all animals?

Which characteristic is common to most, but not necessarily all, animals?

Why are choanoflagellates considered to be closely related to the ancestor of animals?

What was a major morphological criterion used in the traditional classification of animals?

What is the defining characteristic of Bilateria?

What is the biological term for the concentration of sensory organs at the anterior end of the body?

What are germ layers?

Which of the following statements accurately describes the developmental fates of the embryonic germ layers?

What does 'triploblastic' refer to in the context of animal development?

What is a coelomate?

During embryonic development, what type of cleavage results in two tiers of cells, one directly above the other, when the zygote reaches the eight-cell stage?

An eight-cell embryo is separated into individual cells, and each cell develops into a complete, normal adult animal. What type of cleavage does this animal exhibit?

Which statement accurately describes a blastopore?

Molecular techniques have led to revisions in animal phylogenies. Which major change resulted from these techniques?

Traditional and molecular phylogenies disagree on the emphasis of which of the following issues?

What is the term for a horseshoe-shaped crown of ciliated tentacles used by many invertebrates for feeding?

Which distinctive type of larva is shared by several phyla of invertebrates and considered important in phylogeny?

What is the primary characteristic that groups phyla within the Ecdysozoa?

If two organisms that appear quite different share similar genomic DNA sequences, what can be inferred about their evolutionary relationship?

What is ecdysis?

What is the role of the mesoderm in forming a true coelom?

If a species once possessed a coelom but has lost it over time, which function would be most likely affected?

What is the key difference between a pseudocoelom and a true coelom?

You are examining a new animal species in the lab. You find that you can pass a line through any longitudinal plane and find equal halves. Classify the body symmetry of this animal.

Researchers discover a set of genes present in nearly all animals, except Porifera. Assume these are also lacking in Choanoflagellates. What is a valid conclusion?

Which animal phylum has the greatest number of known species?

Echinoderms are classified as Bilateria, but they exhibit radial symmetry as adults. If echinoderms’ genes controlling radial symmetry were investigated, what might scientists find?

Suppose a new animal species is discovered. It is triploblastic, has a true coelom, is cephalized, but lacks body segments. Based on molecular phylogenies, to which phylum could it belong?

A new animal species with indeterminate cleavage is being studied. If one of the early embryonic cells (blastomeres) dies unexpectedly, what is likely to happen to the embryo?

A small amount of DNA from a new species needs to be amplified. Which technique amplifies DNA?

You are comparing the genomes of several closely related animal species. Which type of genetic variation is most likely to provide insights into the unique adaptations of each species?

Certain animal species exhibit segmentation. What is a potential advantage of segmentation?

What is the significance of the Cambrian explosion in animal evolution?

In animal development, what is the archenteron?

Which of the following is an example of convergent evolution in animals?

What type of data contribute to the construction of phylogenetic trees?

How are protostomes and deuterostomes different?

Which of the following scenarios would MOST likely lead to revisions in animal classification?

What characteristic is LEAST likely to be used in determining animal phylogeny?

Which developmental feature is integral to the formation of the endoderm?

Which of the following animal groups is characterized by radial symmetry?

What is the MOST significant implication of Hox genes among diverse animal phyla?

If you discovered a new species with bilateral symmetry, cephalization, and three germ layers, which of the following characteristics would you expect to find?

What role does the blastopore play in deuterostome development?

Which of the following features distinguishes protostomes from deuterostomes?

What does the term 'Eumetazoa' refer to?

Among Ecdysozoa, what biological processes would be most likely disrupted by a mutation affecting the hormones?

Which evolutionary advantage is MOST directly associated with the presence of a coelom?

What defines indeterminate cleavage?

What is the functional significance of the lophophore in lophotrochozoans?

What role did the Cambrian explosion play in animal evolution?

What is a correct evolutionary pathway?

In what way are nematodes and arthropods similar?

Which of the following has radial symmetry?

What evidence would conclude that a protist is closely related to animals?

What can be concluded from a species that is triploblastic and has bilateral symmetry?

What is a characteristic that groups annelids and arthropods?

What trait is exhibited by all animals during some point of development?

What is the importance of the mesoderm?

What is the role of the blastopore in protostomes?

What can be concluded about animal relatedness based on similar segments of DNA?

How do molecular phylogenies classify animals?

What can be said about deuterostomes?

What occurs during ecdysis?

Which trait evolved multiple times in animals?

If an animal lost coelom over evolutionary time, the MOST LIKELY affected function is...

What is the most important concept in the field of population genetics?

What constitutes a gene pool?

From which individuals is the gene pool of the next generation derived?

When calculating allele frequency for a diploid species, how many alleles are present for a single gene in each individual?

In the Hardy-Weinberg equation, which term represents the genotype frequency of heterozygotes?

In the Hardy-Weinberg equation, p + q = _____, where p and q represent _____.

Which phenomenon would violate the conditions required for Hardy-Weinberg equilibrium?

If a population satisfies the Hardy-Weinberg equilibrium model, what can you assume about that population?

Blue flower color (B allele) is dominant to white (b allele). If a population of plants in Hardy-Weinberg equilibrium contains white flowers (bb) at a frequency of 0.04, what is the frequency of the blue flower allele (B)?

Blue flower color (B allele) is dominant to white (b allele). If a population of plants in Hardy-Weinberg equilibrium contains white flowers (bb) at a frequency of 0.04, what is the frequency of the heterozygous genotype?

Microevolution involves what type of changes?

What are the two principal factors that lead to microevolution?

Fitness is a measure of reproductive success. If an individual with genotype BB produces 6 offspring, and a heterozygous individual (Bb) produces 10 offspring, and a third individual with genotype bb produces 5 offspring, what is the fitness value for the individual with BB genotype?

A mutation arises in an individual that decreases its fitness. This means that this individual's:

Over generations in a population, traits seen in individuals with higher fitness values will:

In which type of selection do individuals intermediate in a phenotypic distribution have greater reproductive success?

The human beta-globin gene has two alleles, HS and HA. Individuals that are homozygous for HS have sickle-cell disease and lower fitness. Individuals that are heterozygotes (HSHA) do not show sickle-cell symptoms and have a resistance to malaria. Individuals that are homozygous for HA have the highest fitness but are susceptible to malaria. In areas where malaria is prevalent the HS allele is maintained in the population. Which type of selection is occurring with the beta-globin gene?

In a species of salamander, there are two forms, red and yellow. As the yellow form becomes less common due to predation and the red form more common, the yellow form becomes less likely to be eaten and more likely to survive and reproduce. The yellow form then becomes more common and roles of red and yellow forms reverse. This is an example of:

Male deer have large antlers used to challenge each other in fights for territory and females, with females actively choosing the strongest males. Which type of sexual selection is occurring within the deer population?

What mechanism leads to changes in allele frequencies due to random chance?

There is a population of frogs living in a pond, 25 are green, 25 are brown, 25 are yellow with green spots and 25 are all yellow. A drought occurred and 75% of the frogs died, with the remaining frogs green and brown. After 25 generations the frogs still were green and brown, and yellow frogs never appeared in the population again. Which of the following best explains this phenomenon?

Which of the following would most likely result in a bottleneck event?

GGG and GGC are codons for the amino acid, glycine. A mutation caused the insertion of a cytosine in place of the guanine during DNA replication. Over many generations the DNA changes so that the frequency of GGC is similar to that of GGG. What effect does this mutation have on the population's mean fitness?

What phenomenon tends to increase genetic variation in a population?

Over several generations in a population, inbreeding tends to:

Which of the following is NOT related to genetic drift?

In a small population, both _________ and _________ would violate the conditions of Hardy-Weinberg equilibrium.

Genotype Qq produces 10 offspring per year. Genotype QQ has a fitness value of 0.4 and genotype qq has a fitness value of 0.2. How many offspring does genotype qq produce each year?

Which of the following statements is true regarding Seehausen and van Alphen's African cichlid experiment?

Which type of selection is most likely to lead to an individual with a feature that makes them less likely to survive?

In Seehausen and van Alphen's experiment with cichlids, what would they have concluded if the females responded to the same males regardless of the lighting conditions?

GGG and GGC are codons for the amino acid, glycine. A mutation caused the insertion of a cytosine in place of the guanine during DNA replication. Over many generations the DNA changes so that the frequency of GGC is similar to that of GGG. What is this phenomenon called?

What is a key assumption of the Hardy-Weinberg equilibrium?

Which of the following evolutionary forces consistently leads to adaptation?

What is the likely outcome of prolonged directional selection on a trait?

In a population experiencing heterozygote advantage, what would you expect to observe?

Which of the following scenarios is most likely to lead to the founder effect?

Non-random mating, such as assortative mating, primarily affects:

How does gene flow typically influence the genetic diversity of populations?

Beyond natural selection, what else is fundamentally important in the field of population genetics?

How does the concept of a 'gene pool' contribute to our understanding of evolution at the population level?

Considering the reproductive success of individuals within a population, how does this success directly influence the genetic makeup of subsequent generations?

Why is understanding allele frequencies important for analyzing genetic variation in populations?

In the context of the Hardy-Weinberg equation, how does the term '2pq' specifically enhance our understanding of population genetics?

In the Hardy-Weinberg equation, if 'p' represents the frequency of one allele and 'q' represents the frequency of the other allele for a particular gene in a population, what does the equation 'p + q = 1' signify, and why is it crucial to population genetics?

If a population shows significant deviation from Hardy-Weinberg equilibrium, what are the potential implications for the population's long-term genetic stability and evolutionary trajectory?

How can Hardy-Weinberg equilibrium serve as a null hypothesis when studying evolution in real populations?

In a plant population, the allele for red flowers (R) is dominant over the allele for white flowers (r). If 16% of the population has white flowers and the population is in Hardy-Weinberg equilibrium, what is the predicted frequency of the R allele?

In a population of butterflies, the allele for iridescent wings (I) is dominant to the allele for dull wings (i). If the frequency of butterflies with dull wings is 9%, what is the expected frequency of heterozygous butterflies (Ii) if the population is in Hardy-Weinberg equilibrium?

How does microevolution fundamentally differ from other scales of evolutionary change, such as macroevolution?

What role does new genetic variation play in the process of microevolution?

Consider three genotypes: AA produces 4 offspring, Aa produces 8 offspring, and aa produces 2 offspring. What is the fitness value for the Aa genotype?

If an individual harbors a mutation that reduces its ability to attract mates, how will this affect its evolutionary fitness?

Over time, how do traits associated with higher fitness typically change within a population?

If a population of birds features a range of beak sizes, and those with average beak sizes are more successful at acquiring food and avoiding predation, what kind of selection is likely at play?

In a region with patchy environments, some favoring dark-colored insects and others favoring light-colored insects, which type of selection would most likely occur?

In a scenario where a rare flower color becomes less targeted by herbivores because they haven't yet adapted to it, what type of selection is most likely to occur?

In a population of peacocks, males with the most elaborate and colorful tail feathers are more successful at attracting mates, even though these feathers make them more vulnerable to predators. This is an example of:

If a population of lizards experiences a volcanic eruption that drastically reduces its size, what type of microevolutionary mechanism is most likely to affect the allele frequencies in the surviving population?

A hurricane devastates a coastal bird population. Which scenario describes the bottleneck effect?

If a neutral mutation arises in a population and its frequency increases over many generations, ultimately reaching fixation, what does this indicate about its impact on the population's fitness?

How does gene flow primarily influence the genetic variation within a population?

How does inbreeding affect the genetic composition of a population over successive generations?

Which microevolutionary force would MOST likely be negligible in Hardy-Weinberg equilibrium?

Which group of fishes, long presumed extinct, includes species that were later found living in the wild?

From which structure are the jaws of vertebrates thought to have evolved?

Which pairing of taxonomic category and common name is incorrect?

What biological process involves a significant change in body form during an organism's life cycle?

What anatomical feature characterizes the members of the Class Testudines?

Which anatomical characteristic is a distinguishing feature of the order Squamata?

Which of the following animals are the closest living relatives to crocodiles and alligators?

Among the following reptilian taxa, which has members that are still living?

Which term best describes an animal that generates its own body heat through metabolic processes and retains much of that heat?

What unique feature distinguishes birds from all other extant vertebrates?

What anatomical feature is a defining characteristic of marsupials?

What is a key distinguishing reproductive characteristic of eutherian mammals compared to other mammals?

Which modification would be most critical for a reptile to lose to become as susceptible to dehydration as an amphibian?

What anatomical adaptation would a terrestrial salamander need to evolve to breathe in a similar manner to amniotes?

What key characteristic would allow the curator of an aquarium to differentiate between a lamprey and a hagfish?

How would a fish compensate for the loss of function in its lateral line system?

If a frog loses its ability to perform buccal pumping, what physiological change is MOST likely to provide compensation?

Which of the following statements about amphibian orders contains an inaccuracy?

What is the most likely phenotypic consequence of an inherited mutation resulting in a loss of follicles?

What is the most likely physiological consequence of an infection in a bird's air sacs?

In the Davis and Colleagues experiment on limb length, which mouse genotype would show defects in limb formation?

Which of the following amphibian descriptions is incorrect?

In the Davis and Capecchi experiment, why did certain mutant genotypes have such a pronounced impact specifically on limb development?

What characteristic do the three mammal orders with the highest species counts share?

Which of the following adaptations in fish allows them to maintain buoyancy in the water?

What evolutionary advantage did the development of the amniotic egg provide to reptiles?

How does the four-chambered heart benefit birds and mammals compared to animals with three-chambered hearts?

Which of the following features is unique to mammals?

What is the evolutionary significance of the evolution of jaws in gnathostomes?

Which of the following is an adaptation to improve thermoregulation in endotherms that live in cold environments?

What is the likely effect of a mutation that disables the production of melanin in birds?

How does the allantois, found in amniotic eggs, aid in the development of the embryo?

What is the key difference between the scales of reptiles and the scales of bony fish?

How does the presence of a notochord contribute to the evolutionary success of chordates?

Which adaptation is most important for allowing amphibians to successfully colonize terrestrial habitats?

What role do pheromones play in the social behavior of mammals?

What is the primary advantage of having hinged jaws?

What is the primary role of the operculum in bony fishes?

Which feature contributes most to the efficient unidirectional flow of air through a bird's respiratory system?

Which of the following is the most significant advantage of the evolution of endothermy?

Which evolutionary adaptation in fish contributes to maintaining buoyancy?

What evolutionary advantage did the amniotic egg provide reptiles compared to amphibians?

Compared to animals with three-chambered hearts, what benefit does a four-chambered heart offer birds and mammals?

Which of the following characteristics is exclusive to mammals?

What was the evolutionary significance of the development of jaws in gnathostomes?

Which adaptation is most likely to improve thermoregulation in endotherms inhabiting cold environments?

What is the LEAST likely effect of a mutation that disables the production of melanin in birds?

Which adaptation is the LEAST important for allowing amphibians to successfully colonize terrestrial habitats?

What is the primary advantage derived from having hinged jaws?

Feathers are a crucial defining feature of birds. Which of the subsequent characteristic aids in flight?

What is the MOST significant advantage of the evolution of endothermy?

Imagine a scenario where a species of fish develops a mutation that affects their ability to detect vibrations in the water. Which physiological structure is MOST likely experiencing malformation?

What feature would allow you to distinguish between a salamander and a lizard?

What unique trait possessed by Lampreys affects host organisms?

Which evolutionary feature provides extra oxygen to avian species?