#1 of 34
UHS 2024
Permalink
According to endosymbiosis theory, flagella may have derived by the ingestion of prokaryotes similar to:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:The endosymbiotic theory extends beyond mitochondria and chloroplasts, attempting to explain the origins of cellular motility structures.
Solution:- Lynn Margulis proposed that eukaryotic flagella and cilia originated from a symbiotic relationship with motile, spiral-shaped bacteria.
- Specifically, she suggested they derived from ancient bacteria similar to modern Spirochetes, which attached to the surface of early host cells, eventually becoming the specialized motility appendages we see today.
Why other options are incorrect:- Aerobic bacterium: These are hypothesized to be the ancestors of mitochondria.
- Cyanobacteria (not listed but relevant): Ancestors of chloroplasts.
#2 of 34
NUMS 2024
Permalink
Children of a mason do not inherit strong muscles developed by father due to hard labour. This is an example of:
A
Survival of the fittest
B
Over production of offspring
C
Not inheriting acquired characters
D
Use and disuse of organs
View Answer & Propolis Autopsy
Correct Key: Option C
Diagnostic Explanation
Concept:Modern genetics draws a strict line between somatic (body) cells and germ-line (reproductive) cells.
Solution:- A mason develops strong muscles due to intense physical labor (an acquired, somatic trait).
- Because this environmental stress does not alter the DNA sequence in the mason's sperm cells, the muscular phenotype cannot be passed to his offspring.
- This scenario is a direct textbook refutation of Lamarckism, perfectly demonstrating the principle of not inheriting acquired characters.
Why other options are incorrect:- This situation highlights the failure of the "Use and disuse" theory to explain inheritance, making option C the exact descriptive conclusion of the phenomenon.
#3 of 34
SZABMU 2024
Permalink
Which of the following is the main point of Darwinism?
A
Descent with modification
B
Use and disuse of organ
C
Inheritance of acquired characters
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Darwin summarized his entire evolutionary theory into a single, elegant phrase.
Solution:- The central, overarching theme of Darwinism is Descent with modification.
- This concept means that all current living species are descendants of older, ancestral species. As lineages branched off through generations, they accumulated modifications (adaptations) suited to their specific ways of life.
Why other options are incorrect:- Use and disuse / Acquired characters: These are the main points of Lamarckism.
- Artificial Selection: This was a tool Darwin used to explain natural selection, not the main point of biological evolution itself.
#4 of 34
SZABMU 2024
Permalink
The Darwin's observation on discovery and investigation on fossils is called
View Answer & Propolis Autopsy
Correct Key: Option D
Diagnostic Explanation
Concept:Different fields of biological science provide distinct lines of evidence for evolution.
Solution:- The scientific study of prehistoric life through the discovery, investigation, and analysis of fossils is strictly known as Paleontology.
- Darwin used paleontological evidence extensively to show that ancient extinct species shared similarities with modern living species (e.g., giant fossil sloths compared to living tree sloths in South America).
Why other options are incorrect:- Biogeography: The study of the geographical distribution of species.
- Homology: The study of structural similarities due to shared ancestry.
- Chronology: The general study of time and historical order.
#5 of 34
KMU 2024
Permalink
The embryological stages of anatomical features show similarity in:
D
Human, jelly fish and mouse
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Comparative embryology reveals profound ancestral similarities that are often lost by adulthood.
Solution:- During early embryonic development, all vertebrates (fishes, amphibians, reptiles, birds, and mammals) look astonishingly similar.
- They all develop a post-anal tail and pharyngeal gill slits/pouches at some stage in their embryogenesis.
- This shared developmental pathway is strong evidence that all vertebrates descended from a common aquatic ancestor.
Why other options are incorrect:- All living things: Plants and fungi do not share vertebrate embryological stages.
- Jellyfish: Jellyfish are invertebrates (Cnidarians) and have entirely different embryological development (they lack a mesoderm and notochord).
#6 of 34
SZABMU 2024 Reconduct
Permalink
The reduction of population size with some specific allele and genotype due to natural disaster is called:
View Answer & Propolis Autopsy
Correct Key: Option C
Diagnostic Explanation
Concept:Genetic drift can drastically alter allele frequencies when populations undergo rapid, unselective downsizing.
Solution:- When a sudden environmental catastrophe (like a flood, fire, or earthquake) indiscriminately wipes out a large portion of a population, the surviving individuals may not genetically represent the original population.
- This severe, random reduction in population size and genetic diversity is called the Bottleneck effect.
Why other options are incorrect:- Founder effect: Occurs when a few individuals willingly migrate and establish a new isolated colony, not due to a disaster killing the majority.
- Mutation: The creation of a new allele, not the destruction of a population.
#7 of 34
SZABMU 2024 Reconduct
Permalink
When humans purposefully apply selection pressure to populations, the process is known as:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Evolutionary mechanisms can be steered by human intent.
Solution:- Artificial selection (or selective breeding) occurs when humans purposefully act as the selective pressure.
- By deliberately breeding individuals that possess favorable traits (e.g., higher milk yield in cows, larger kernels in corn), humans accelerate and direct evolutionary changes within a population over relatively few generations.
Why other options are incorrect:- Natural selection: Selection is driven entirely by natural environmental factors, without any purposeful intent.
- Genetic drift: A totally random change in allele frequencies due to chance events, unrelated to purposeful selection.
#8 of 34
SZABMU 2023
Permalink
A general formula is derived by one of the following scientist for calculating the frequencies of alleles and genotypes in population at equilibrium:
View Answer & Propolis Autopsy
Correct Key: Option D
Diagnostic Explanation
Concept:Population genetics relies on mathematical models to determine if an evolving population is stable (in equilibrium).
Formula:$$p^2 + 2pq + q^2 = 1$$
Solution:- G.H. Hardy (a mathematician) and Wilhelm Weinberg (a physician) independently derived this principle in 1908.
- The Hardy-Weinberg equation allows scientists to calculate expected allele and genotype frequencies in a stable, non-evolving population under ideal conditions.
Why other options are incorrect:- Darwin/Lamarck/Linnaeus: These prominent early biologists did not develop the mathematical foundations of population genetics; their work preceded the integration of genetics and evolution (the Modern Synthesis).
#9 of 34
SZABMU 2023
Permalink
When humans purposefully apply selection pressure to populations, the process is known as:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Selection pressure can be exerted either by environmental factors or by intentional human intervention.
Solution:- When humans act as the selective agent—choosing specific plants or animals with desirable traits to reproduce—the process is called Artificial selection.
- This method has been used for millennia to create modern agricultural crops, livestock breeds, and dog breeds from wild ancestors.
Why other options are incorrect:- Natural selection: The environment dictates survival and reproductive success, not human preference.
- Genetic drift: A random fluctuation in allele frequencies, not a purposeful selection.
#10 of 34
UHS 2023
Permalink
Which of the following is not an example of disuse of organs?
View Answer & Propolis Autopsy
Correct Key: Option C
Diagnostic Explanation
Concept:The "use and disuse" theory (Lamarckism) or the modern concept of vestigial organs refers to anatomical structures losing function over evolutionary time due to lack of environmental necessity.
Solution:- The shedding of milk teeth (deciduous teeth) is a programmed, physiological developmental process that occurs in all mammals to make way for permanent adult teeth.
- It is an active developmental stage, not an evolutionary consequence of an organ being "disused" over generations.
Why other options are incorrect:- Snake's legs / Ear muscles: These are classic vestigial structures resulting from long-term evolutionary disuse.
- Muscle atrophy: Results from short-term physical disuse in an individual's lifetime.
#11 of 34
SZABMU 2023
Permalink
Which statement is not correct for the Darwin's theory of natural selection?
A
Survival in the struggle for existence is random
B
The fit individuals leave more offsprings into their environment
C
The unequal ability of individuals to survive and reproduce will lead to a gradual
D
Accumulation over the generations thus leading to the evolution of a new species
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Natural selection is highly deterministic, not a random lottery.
Solution:- The statement "Survival in the struggle for existence is random" is strictly incorrect.
- Darwin's theory explicitly states that survival is heavily influenced by inherited traits.
- Organisms with variations best suited to the local environment are naturally selected to survive and reproduce, making the process decidedly non-random.
Why other options are incorrect:- B, C, and D are all core, accurate tenets of Darwin's theory: Fit individuals reproduce more, causing a gradual accumulation of advantageous traits that can eventually lead to speciation.
#12 of 34
ETEA 2023 Retake
Permalink
According to Neo-Darwinism, which of the following is a cause of evolution?
B
Infinite large population
C
Environmental stability
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Neo-Darwinism (the Modern Synthesis) combines Darwinian natural selection with Mendelian genetics and modern population dynamics to explain speciation.
Solution:- Reproductive isolation is a primary driver of macroevolution and speciation.
- When populations are prevented from interbreeding (due to geographic, temporal, or behavioral barriers), their gene pools diverge over time due to differing selective pressures and genetic drift, ultimately forming new species.
Why other options are incorrect:- Infinite large population: According to the Hardy-Weinberg principle, an infinitely large population actually prevents evolution (genetic drift is minimized, maintaining equilibrium).
- Environmental stability: Stable environments limit evolutionary change, whereas changing environments force adaptation.
#13 of 34
UHS 2023
Permalink
Which of the following type of organs are supposed to be functional in ancestral species rather than in present day species:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Evolutionary baggage is often carried forward in a species' anatomy long after it ceases to be useful.
Solution:- Vestigial organs are anatomical features that were fully developed and highly functional in a species' evolutionary ancestors.
- As the organism evolved and adapted to new environmental niches, these organs lost their original purpose.
- Consequently, they became reduced in size and function in present-day descendants (e.g., the human appendix, whale pelvis).
Why other options are incorrect:- Homologous / Analogous organs: These describe highly functional organs in present-day organisms compared across different species.
#14 of 34
ETEA 2023
Permalink
All of the following paired organs/structures have homology except:
B
Bat's wing: Wings of butterfly
C
Horse front leg: Front flappers of whale
D
Wings of bird: wings of flying lizards
View Answer & Propolis Autopsy
Correct Key: Option B
Diagnostic Explanation
Concept:Homologous structures arise from shared ancestry, while analogous structures arise from convergent evolution due to similar functional demands.
Solution:- Homology implies a shared embryonic origin and underlying bone structure (e.g., the pentadactyl limb).
- A Bat's wing (mammalian bone structure) and the Wings of a butterfly (insect chitin structure) do not share a common ancestral origin.
- They only share a function (flight), making them purely analogous structures, not homologous.
Why other options are incorrect:- Human hand & Bat wing / Horse leg & Whale flipper / Bird wing & Lizard wing: All these pairs represent tetrapod forelimbs derived from a common reptilian/amphibian ancestor, thus they are homologous.
#15 of 34
ETEA 2023
Permalink
Identify fossil bird among the following:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Transitional fossils provide a snapshot of evolution in progress, linking major vertebrate groups.
Solution:- Archaeopteryx (meaning "ancient wing") is the most famous fossil linking non-avian theropod dinosaurs to modern birds.
- It lived during the Late Jurassic period and possessed a mix of reptilian features (teeth, long bony tail) and avian features (flight feathers, wishbone).
Why other options are incorrect:- Equus: The modern genus of horses, zebras, and donkeys.
- Dawn horse (Eohippus/Hyracotherium): An early fossil ancestor of the horse, not a bird.
- Python: A modern extant genus of non-venomous snakes.
#16 of 34
NUMS 2023
Permalink
This theory states that 'mitochondria and chloroplasts are, in effect, ancient bacteria which now live inside the larger cells':
A
Darwin's theory of evolution
B
Endosymbiont hypothesis
View Answer & Propolis Autopsy
Correct Key: Option B
Diagnostic Explanation
Concept:The origin of complex eukaryotic cells is explained by the assimilation of simpler prokaryotic cells.
Solution:- The Endosymbiont hypothesis (formulated robustly by Lynn Margulis) proposes that crucial eukaryotic organelles (mitochondria and chloroplasts) originated as free-living ancient bacteria.
- These bacteria were engulfed by a primitive host cell, forming a mutually beneficial (symbiotic) relationship.
- Evidence includes the fact that mitochondria and chloroplasts have their own circular DNA, ribosomes, and reproduce via binary fission, exactly like modern bacteria.
Why other options are incorrect:- Darwinism, Neo-Darwinism, and Lamarckism describe macro/micro-evolutionary mechanisms at the population and organismal level, not the specific cellular origins of organelles.
#17 of 34
NUMS 2023
Permalink
The organs which are similar in functions but differ in structure are called:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:When unrelated lineages face similar environmental pressures, they may evolve similar adaptations independently.
Solution:- Structures that serve the same purpose (e.g., flight, swimming) but have entirely different evolutionary origins and internal anatomy are called Analogous organs.
- They are the direct result of convergent evolution. Examples include insect wings vs. bird wings, or the streamlined shape of sharks (fish) and dolphins (mammals).
Why other options are incorrect:- Homologous organs: Similar structural origin, but often adapted for different functions.
- Convergent/Divergent: These terms describe the evolutionary process, while "analogous/homologous" strictly name the organs themselves.
#18 of 34
ETEA 2023
Permalink
Who formulated the principle that 'ontogeny recapitulates phylogeny'?
View Answer & Propolis Autopsy
Correct Key: Option B
Diagnostic Explanation
Concept:Early comparative embryology sought to link developmental stages to evolutionary history.
Solution:- The German biologist Ernst Haeckel formulated the Biogenetic Law, famously summarized as "ontogeny recapitulates phylogeny."
- This phrase suggests that the developmental stages of an embryo (ontogeny) represent an accelerated playback of its species' evolutionary history (phylogeny).
- While historically significant, modern science views this as an oversimplification; embryos share similarities because they share common ancestral developmental genes, not because they literally become adult versions of their ancestors in the womb.
Why other options are incorrect:- Von Baer: Formulated rules of embryology that actually opposed Haeckel's strict recapitulation theory.
- Darwin / Spencer: Did not coin this specific embryological principle.
#19 of 34
ETEA 2022
Permalink
The term 'survival of the fittest' was used by:
View Answer & Propolis Autopsy
Correct Key: Option B
Diagnostic Explanation
Concept:The term "survival of the fittest" refers to the reproductive success of organisms best suited to their environment. It is closely associated with natural selection.
Solution:- British philosopher and sociologist Herbert Spencer first coined the phrase "survival of the fittest" after reading Charles Darwin's On the Origin of Species.
- He applied this concept to human societies and economics, a doctrine later known as Social Darwinism.
- Darwin later adopted the phrase in the 5th edition of his book as a synonym for natural selection.
Why other options are incorrect:- Darwin: Formulated the theory of natural selection but did not coin this specific phrase.
- Lamarck: Known for the theory of inheritance of acquired characteristics.
- Mayr: A prominent 20th-century evolutionary biologist known for the biological species concept.
#20 of 34
NUMS 2022
Permalink
He presented the theory of 'origin of species by means of natural selection:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:The publication of evolutionary theories fundamentally shifted biological sciences in the 19th century.
Solution:- Charles Darwin wrote and published the groundbreaking book "On the Origin of Species by Means of Natural Selection" in 1859.
- This work introduced the concept that populations evolve over generations through a process of natural selection.
Why other options are incorrect:- Lamarck: Published his theory of evolution based on the inheritance of acquired characteristics much earlier (1809).
- Linnaeus: The father of modern taxonomy; he believed in the fixity of species.
- Hardy-Weinberg: Developed a mathematical baseline for population genetics in the early 20th century.
#21 of 34
ETEA 2022
Permalink
The raw material that is used by natural selection for better survival is/are:
View Answer & Propolis Autopsy
Correct Key: Option D
Diagnostic Explanation
Concept:Natural selection cannot operate without differences among individuals in a population.
Solution:- Mutations are the ultimate source of new alleles and genetic novelties.
- These mutations lead to variations within a population.
- Natural selection acts upon these variations, selecting for traits that enhance survival and reproduction in a specific environment.
- Therefore, both variation and mutation act as the raw material for evolutionary change.
Why other options are incorrect:- Similarity only: Clones with identical genetics offer no variation for natural selection to act upon; the population would be equally susceptible to environmental pressures.
- Selecting "only" variation or "only" mutation is incomplete, as they are inherently linked in providing evolutionary raw material.
#22 of 34
ETEA 2022
Permalink
A small biological unit that can evolve over time is ____
View Answer & Propolis Autopsy
Correct Key: Option B
Diagnostic Explanation
Concept:Evolution operates on groups of interbreeding individuals, not on solitary entities.
Solution:- An individual organism cannot evolve during its lifetime; it can only develop or acclimate.
- Evolution is defined as the change in allele frequencies over time.
- The smallest biological unit capable of exhibiting this change over successive generations is a population.
Why other options are incorrect:- An organism / Cell: Individuals do not evolve; they retain the same genetic sequence from birth to death.
- A specie: While species evolve, a population is a smaller, localized unit of a species that is the fundamental operating level of microevolution.
#23 of 34
BUMHS 2022
Permalink
Who held to the concept of unity of life?
View Answer & Propolis Autopsy
Correct Key: Option B
Diagnostic Explanation
Concept:The "unity of life" is a foundational evolutionary concept describing the shared ancestry of all living organisms.
Solution:- Charles Darwin emphasized the "unity of life" in his theory of descent with modification.
- He proposed that all organisms are related through descent from a common ancestor that lived in the remote past.
- He visualized the history of life as a branching tree, showing how diverse species share common biological characteristics due to shared lineages.
Why other options are incorrect:- Aristotle: Believed species were fixed and arranged them on a strict hierarchy (Scala Naturae).
- Lamarck: Focused on linear progression toward perfection rather than a unified branching descent from a single ancestor.
#24 of 34
DUHS 2022
Permalink
Evolution is transformation of the form and mode of existence of an organism in such manner that the descendants differ from their ancestor, according to:
View Answer & Propolis Autopsy
Correct Key: Option B
Diagnostic Explanation
Concept:The core definition of evolution encompasses the gradual change of populations resulting in descendants that are distinct from their ancestors.
Solution:- Charles Darwin defined evolution fundamentally as "descent with modification."
- This means that as lineages progress through time, they accumulate genetic and phenotypic changes, transforming their form and mode of existence so that modern descendants differ significantly from their ancient ancestors.
Why other options are incorrect:- Lamarck: Argued for inheritance of acquired characteristics, a specific incorrect mechanism.
- Weismann: Famous for the germ-plasm theory, disproving Lamarckism.
- Mendel: The father of genetics who discovered inheritance laws, not the broader theory of evolutionary transformation.
#25 of 34
SZABMU 2022
Permalink
Among the oldest known fossils comes the:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:The fossil record provides a chronological history of life on Earth, showing a progression from simple unicellular life to complex multicellular organisms.
Solution:- The oldest undisputed fossil evidence points to the existence of prokaryotes (ancient bacteria).
- These fossilized remnants (often found in stromatolites) date back approximately 3.5 billion years.
- All other complex life forms (fishes, amphibians, reptiles) evolved much later in Earth's geological history.
Why other options are incorrect:- Fishes, amphibians, and reptiles are all vertebrates (eukaryotes) that appeared hundreds of millions of years ago, which is billions of years after prokaryotes.
#26 of 34
ETEA 2022
Permalink
The Archaeopteryx is a fossil bird which possesses the characters of both:
C
Amphibians and reptiles
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Transitional fossils exhibit traits common to both an ancestral group and its derived descendant group.
Solution:- Archaeopteryx is one of the most famous transitional fossils in paleontology.
- It shows strong evidence that birds evolved from theropod reptiles (dinosaurs).
- It possessed reptilian characters (a long bony tail, teeth, and claws on its wings) alongside avian (bird) characters (feathers and wings).
Why other options are incorrect:- It lacks characteristics tying it directly to amphibians, fishes, or mammals in a transitional sense.
#27 of 34
DUHS 2022
Permalink
Presence of remnant of pelvic girdle in whale and snake although they never have legs show evidence from:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Evolution leaves anatomical "clues" in modern organisms that point to the physical structures of their ancestors.
Solution:- Whales and snakes evolved from four-legged (tetrapod) ancestors.
- Over time, as their mode of locomotion changed, the functional need for hind legs was lost.
- The remnants of the pelvic girdle and hind limb bones found inside their bodies are vestigial organs—structures reduced in size and lacking their original function, providing powerful evidence of descent with modification.
Why other options are incorrect:- Paleontology: Involves the study of fossils, not structures in living organisms.
- Biochemical / Embryology: Refers to DNA/proteins and developmental stages, respectively, rather than adult anatomical remnants.
#28 of 34
DUHS 2022
Permalink
Artificial selection in breeding provides evidence for evolution is known as:
View Answer & Propolis Autopsy
Correct Key: Option D
Diagnostic Explanation
Concept: Selective breeding mechanisms.
Solution: Artificial selection operates when breeders deliberately select organisms exhibiting a desired trait to parent the next generation, demonstrating that species traits can change over time.
#29 of 34
DUHS 2022
Permalink
The organs perform same functions in different groups of organisms but are different in this internal structure called as:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Different evolutionary lineages can independently develop similar adaptations in response to similar environmental challenges.
Solution:- Structures that look similar and perform the same functions but have completely different internal anatomy and embryonic origins are called Analogous organs.
- For example, the wing of a bat (mammal) and the wing of a butterfly (insect) are both used for flight, but their internal structures are unrelated.
- This represents convergent evolution.
Why other options are incorrect:- Homologous organs: Have the same internal structure but often different functions (divergent evolution).
- Symmetry: Refers to body plans, not specific structural adaptations.
#30 of 34
PMC 2020
Permalink
This theory says that mitochondria and chloroplasts are in fact ancient bacteria which now live inside the larger cells.
A
Darwin's theory of evolution
View Answer & Propolis Autopsy
Correct Key: Option C
Diagnostic Explanation
Concept:The origin of eukaryotic organelles is a key evolutionary concept explaining how complex cells developed from simpler prokaryotic ancestors.
Solution:- The Endosymbiotic theory (or endosymbiont hypothesis) states that mitochondria and chloroplasts were once free-living ancient bacteria (prokaryotes).
- They were engulfed by an ancestral eukaryotic cell and established a mutually beneficial (symbiotic) relationship.
- Mitochondria are thought to derive from aerobic eubacteria, while chloroplasts derive from photosynthetic bacteria (cyanobacteria).
Why other options are incorrect:- Darwin's theory / Neo-Darwinism: Focus on natural selection and genetic variation on a macroscopic or population scale, not the specific intracellular origin of organelles.
- Lamarckism: Focuses on the inheritance of acquired traits based on use and disuse, which is historically inaccurate.
#31 of 34
PMC 2020
Permalink
____ occurs because natural selection gives some alleles a better chance of survival than others.
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Natural selection acts on the genetic variation within a population, favoring alleles that confer a survival and reproductive advantage.
Solution:- When specific alleles provide a survival advantage, they increase in frequency over generations.
- This gradual change in the genetic makeup (allele frequencies) of a population over time is the very definition of Evolution.
Why other options are incorrect:- Fitness: This is the measure of reproductive success, not the resulting process of change itself.
- Crossing over: A mechanism during meiosis that creates genetic variation, but it is not caused by natural selection.
- Artificial selection: This is driven by human preference, not natural environmental pressures.
#32 of 34
PMC 2020
Permalink
The organs which are similar in function but different in structure, are called:
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:Comparative anatomy helps classify evolutionary pathways based on structural similarities and functional adaptations.
Solution:- Analogous organs are structures that perform a similar function (e.g., flying) but have entirely different underlying anatomical blueprints and embryonic origins.
- Examples include the wings of insects and the wings of birds.
- They arise due to convergent evolution, where unrelated species adapt to similar environmental pressures.
Why other options are incorrect:- Homologous organs: Have the same structural origin but may perform different functions (e.g., human arm and bat wing).
- Convergent/Divergent evolution: These are evolutionary processes, whereas the question specifically asks for the name of the organs.
#33 of 34
MDCAT 2017
Permalink
According to the theory of natural selection, organisms produce:
A
More offspring than supported
B
Less offspring than supported
C
Offspring according to the resources available
D
Offspring to create resources
View Answer & Propolis Autopsy
Correct Key: Option A
Diagnostic Explanation
Concept:A fundamental premise of Darwinian evolution is the inherent capacity of populations to grow exponentially if unconstrained by environmental limits.
Solution:- Darwin observed that all species are capable of producing more offspring than the environment can support.
- This overproduction leads to a struggle for existence (competition for limited resources such as food, space, and mates).
- Only a fraction of these offspring survive to reproduce, which drives the mechanism of natural selection.
Why other options are incorrect:- If organisms produced equal or fewer offspring than resources could support, there would be no intense competition, and a primary driver of natural selection would be absent.
#34 of 34
KMDC 2014
Permalink
Vestiges of vestigial organs are those organs which have ceased to be of any use in their possessor but they persist to reduce from generation after generation. In man, they are:
View Answer & Propolis Autopsy
Correct Key: Option D
Diagnostic Explanation
Concept:Vestigial organs are historical remnants of anatomical structures that served a functional purpose in an organism's evolutionary ancestors but have lost most or all of their original function.
Solution:- Vermiform appendix: A remnant of a larger cecum used by herbivorous ancestors to digest cellulose.
- Coccyx (tailbone): The remnant of a lost tail from primate ancestors.
- Nictitating membrane (plica semilunaris): A remnant of a functional third eyelid found in other vertebrates like reptiles and birds.
- Therefore, All A, B, C are vestigial structures in humans.
Why other options are incorrect:- Choosing only A, B, or C is incorrect because all three are classic textbook examples of human vestigial organs.
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