Evolution of Life is part of Biology. Below are notes on 9 sub-topics, followed by practice MCQs from State PSC and UPSC papers.

Evidences for Evolution: Paleontological, comparative anatomy, embryological, molecular, biogeographical.

  • Paleontological Evidence (Fossils): Study of preserved remains/traces of past life. Demonstrates gradual changes in life forms over geological time.
  • Connecting Links (Transitional Fossils): Organisms showing features of two different groups, indicating evolutionary transitions.
  • Archaeopteryx: A connecting link fossil between Reptiles (skeletal features, teeth, bony tail) and Aves (feathers, wishbone).
  • Living Fossils: Organisms that have changed little over millions of years and resemble their fossil ancestors.
  • Peripatus (velvet worm): A living fossil connecting Annelida and Arthropoda. Other examples include Limulus (King Crab) and Latimeria (Coelacanth).
  • Comparative Anatomy & Morphology: Comparison of structural features among different organisms.
  • Homologous Organs: Similar in structure and origin, but different in function. Indicate common ancestry (divergent evolution). E.g., forelimbs of mammals (human arm, whale flipper, bat wing).
  • Analogous Organs: Different in structure and origin, but similar in function. Indicate convergent evolution. E.g., wings of insects and birds.
  • Vestigial Organs: Reduced or non-functional organs in an organism, functional in ancestors. E.g., human appendix, wisdom teeth, pelvic girdle in whales.
  • Embryological Evidence: Similarities in early embryonic development among different species suggest common ancestry. E.g., transient presence of gill slits and a tail in vertebrate embryos (fish, birds, mammals).
  • Molecular Evidence: Similarities in DNA, RNA, and protein sequences (e.g., cytochrome c, hemoglobin) indicate evolutionary relatedness; more similar sequences imply closer common ancestry. The universal genetic code supports a common origin of life.
  • Biogeographical Evidence: Geographical distribution of species. Distribution patterns are influenced by evolution, speciation, and continental drift.
  • Adaptive Radiation: Diversification of species from a common ancestor to fill different ecological niches, often observed in isolated geographical areas (e.g., Darwin's finches on the Galapagos Islands, Australian marsupials).

Human Evolution: Primate ancestry, hominid lineage, key evolutionary changes (bipedalism, brain size, tool use).

  • Primate Ancestry:
  • Primates evolved ~55-85 million years ago (MYA).
  • Shared traits: Grasping hands/feet, stereoscopic vision, relatively large brains, slow life history.
  • Hominid Lineage:
  • Hominoids (apes) diverged from Old World monkeys ~25-30 MYA.
  • Hominins (human lineage) diverged from chimpanzees ~6-7 MYA.
  • Early Hominins (~7-4.4 MYA): Sahelanthropus, Orrorin, Ardipithecus – earliest evidence of bipedalism.
  • Australopithecus (~4.2-2 MYA): Fully bipedal, small brain (400-500 cc), e.g., A. afarensis (Lucy).

tralopiths, specialized chewing adaptations.

first to use stone tools (Oldowan), brain size 600-750 cc.

  • Homo erectus (~1.9 MYA - 143,000 years ago): First to leave Africa, controlled fire, Acheulean tools (hand axes), brain size 800-1200 cc.
  • Homo neanderthalensis (~400,000-40,000 years ago): Europe/Asia, Mousterian tools, larger brain than modern humans (avg. 1200-1700 cc), complex culture.
  • Homo sapiens (~300,000 years ago present): Originated in Africa, complex culture, language, advanced tools, brain size 1300-1400 cc.
  • Key Evolutionary Changes:
  • Bipedalism:
  • Defined hominins, evolved ~6-7 MYA.
  • Advantages: Free hands for carrying/tool use, improved visibility, thermoregulation, efficient long-distance travel.
  • Skeletal adaptations: Foramen magnum repositioning, S-shaped spine, bowl-shaped pelvis, angled femurs, arched feet.
  • Brain Size:
  • Gradual increase, significant growth in Homo genus.
  • Australopithecus (400-500 cc) → H. habilis (600-750 cc) → H. erectus (800-1200 cc) → H. sapiens (1300-1400 cc).
  • Associated with complex cognition, language development, and problem-solving.
  • Tool Use:
  • Earliest undisputed evidence: Homo habilis with Oldowan stone tools (simple choppers, flakes) ~2.8 MYA.
  • H. erectus developed Acheulean tools (hand axes).
  • H. neanderthalensis used Mousterian tools (prepared core technique).
  • H. sapiens developed advanced Upper Paleolithic tools (blades, bone, antler), composite tools, and art.
  • Impact: Enhanced hunting/scavenging, food processing, defense, and manipulation of environment, driving further cognitive evolution.
  • Macroevolution: Evolutionary change occurring at or above the species level; large-scale patterns over geological time.
  • Major Evolutionary Trends:
    • Adaptive Radiation: Diversification of a single ancestral species into multiple species, each adapted to a different ecological niche (e.g., Darwin's finches).
    • Convergent Evolution: Unrelated species independently evolve similar traits due to similar environmental pressures (e.g., wings in birds and bats).
    • Divergent Evolution: Related species evolve different traits, leading to new species, often due to different environmental pressures (e.g., polar bear and grizzly bear).
    • Coevolution: Two or more species reciprocally influence each other's evolution (e.g., predator-prey relationships, plant-pollinator interactions).
    • Punctuated Equilibrium: Evolutionary change characterized by long periods of stasis (no change) interspersed with brief periods of rapid speciation.
  • Mass Extinctions: Rapid, widespread decrease in Earth's biodiversity.
    • The "Big Five" Mass Extinctions: Late Ordovician: (Approx. 443 1. Ma) Global cooling, glaciation, sea-level fall. Late Devonian: (Approx. 372 2. Ma) Ocean anoxia, climate cooling, possibly bolide impacts. Permian-Triassic (P-T/Great 3. Dying): (Approx. 252 Ma) Largest extinction event; linked to Siberian Traps volcanism, massive CO2 release, global warming, ocean anoxia, ocean acidification. Late Triassic: (Approx. 201 Ma) 4. Volcanism (Central Atlantic Magmatic Province - CAMP), climate change. Cretaceous-Paleogene (K-Pg): 5. (Approx. 66 Ma) Wiped out nonavian dinosaurs; linked to Chicxulub asteroid impact and Deccan Traps volcanism.
    • Causes of Mass Extinctions (General): Large Igneous Province (LIP) volcanism, asteroid impacts, drastic climate change (global warming/cooling), sealevel fluctuations, ocean anoxia, ocean acidification.
    • Sixth Mass Extinction (Anthropocene): Ongoing extinction event driven by human activities (habitat destruction, climate change, pollution, invasive species, overexploitation).
  • Dodo and Ecological Interdependence: The extinction of the Dodo (Raphus cucullatus), a flightless bird endemic to Mauritius around 1662, is a classic example of the ecological impact of species loss. Its extinction severely hindered the germination of seeds from the Calvaria Tree (Sideroxylon grandiflorum or tambalacoque) because the seeds required passage through the Dodo's digestive tract for scarification (breaking dormancy) to germinate.

Mechanisms

of

Evolution:

Mutation,

recombination, gene flow, genetic drift (founder

effect, bottleneck effect).

  • Mutation: Sudden, heritable change in the DNA sequence (genetic material), serving as the primary source of new alleles and genetic variation.
  • Mutation Theory of Evolution: Enunciated by Hugo de Vries, proposing that evolution occurs through large, sudden, and discontinuous changes called 'saltation' (single-step large mutation), which contrasts with Darwin's gradualism.
  • Recombination: Reshuffling of existing genetic material through processes like crossing over and independent assortment during meiosis, creating new combinations of alleles.
  • Gene Flow (Migration): Transfer of alleles between populations due to the movement of individuals or gametes, which tends to increase genetic similarity between populations and can introduce new alleles.
  • Genetic Drift: Random fluctuations in allele frequencies from one generation to the next, particularly impactful in small populations; can lead to the loss or fixation of alleles, thus reducing genetic variation within populations.
  • Founder Effect: A type of genetic drift where a new population is established by a small number of individuals (founders) from a larger population; the new gene pool may not be representative of the original population, often leading to reduced genetic diversity and unique allele frequencies.
  • Bottleneck Effect: A type of genetic drift occurring when a population undergoes a drastic reduction in size due to a catastrophic event (e.g., natural disaster, disease); the surviving population's gene pool may have significantly altered allele frequencies and reduced genetic diversity compared to the original, larger population.

Modern Synthetic Theory of Evolution (Neo-Darwinism): Genetic basis of variation, role of population genetics.

  • Modern Synthetic Theory of Evolution (NeoDarwinism) integrates Darwinian natural selection with Mendelian genetics.
  • It defines evolution as a change in allele frequencies within a population over generations.
  • Genetic basis of variation: Primary sources are gene mutations, chromosomal aberrations, and genetic recombination (crossing over).
  • Mutation: Random, heritable changes in DNA, providing raw material for evolution.
  • Hugo de Vries: Proposed the Mutation Theory, suggesting that evolution occurs through sudden, large changes (saltation).
  • Recombination: Shuffling of existing alleles during sexual reproduction (meiosis).
  • Role of Population Genetics: Studies genetic variation within populations and how forces like natural selection, genetic drift, gene flow, and mutation change allele and genotype frequencies in a gene pool.
  • Hardy-Weinberg principle describes genetic equilibrium in the absence of evolutionary forces.
  • Charles Darwin: Proposed the Theory of Evolution primarily by Natural Selection.
  • Beadle and Tatum: Proposed the "one gene one enzyme" hypothesis, linking genes to specific protein (enzyme) synthesis.
  • Jacob and Monod: Proposed the Operon concept, explaining gene regulation in prokaryotes (e.g., Lac Operon).

Natural Selection: Types (directional, stabilizing, disruptive), sexual selection, adaptive radiation.

  • Natural Selection: Differential survival and reproduction of individuals based on heritable phenotypic differences, leading to an increase in frequency of advantageous traits in a population over generations.
  • Types of Natural Selection:
    • Directional Selection: Favors one extreme phenotype, shifting the population's trait average towards that extreme over generations.
      • Example: Industrial melanism in peppered moths, development of antibiotic/pesticide resistance, loss of limbs in snakes (natural selection favoring reduced or absent limbs for adaptation to burrowing life).
    • Stabilizing Selection: Favors intermediate phenotypes and acts against extreme variations, reducing phenotypic diversity around the mean.
      • Example: Human birth weight (intermediate weight babies have highest survival rates).
    • Disruptive Selection: Favors both extreme phenotypes over intermediate ones, potentially leading to a bimodal trait distribution and eventually speciation.
      • Example: Beak size in African finches (specialized for different seed types).
  • Sexual Selection: A specific form of natural selection where individuals compete for mates, favoring traits that increase mating success, even if they may decrease survival.
    • Often results in sexual dimorphism (distinct phenotypic differences between sexes).
    • Intrasexual Selection: Competition within one sex for access to mates (e.g., male-male combat).
    • Intersexual Selection: Mate choice, typically by one sex (often females) choosing mates based on specific desirable traits (e.g., peacock's tail display).
  • Adaptive Radiation: Rapid evolutionary diversification of a single ancestral lineage into multiple new species, each adapted to occupy different ecological niches.
    • Typically occurs when a species colonizes a new environment with abundant unoccupied ecological opportunities.
    • Examples: Darwin's finches on the Galapagos Islands, Australian marsupials, Hawaiian honeycreepers.

Origin of Life: Chemical evolution, abiogenesis, Oparin-Haldane hypothesis, Miller-Urey experiment.

Miller-Urey

experiment.

  • Abiogenesis: The process by which life arose from non-living matter.
  • Chemical Evolution (Chemogeny): Gradual process where simple inorganic molecules on early Earth underwent chemical reactions to form complex organic molecules.
  • Oparin-Haldane Hypothesis (1920s):
    • Life originated in a primitive Earth atmosphere that was reducing (lacked free O2) and contained methane (CH4), ammonia (NH3), water vapor (H2O), and hydrogen (H2).
    • Energy sources (UV radiation, lightning, volcanic activity) converted these inorganic molecules into simple organic ones (e.g., amino acids, sugars).
    • These organic molecules accumulated in the oceans, forming a "primordial soup" or "hot dilute soup."
    • Further reactions led to complex organic polymers (proteins, nucleic acids) and eventually self-replicating structures (coacervates/protobionts).
  • Miller-Urey Experiment (1953):
    • Simulated primitive Earth conditions to test the Oparin-Haldane hypothesis.
    • Setup: A closed apparatus with water (simulating oceans), methane, ammonia, hydrogen (simulating early atmosphere), and electrodes for electrical discharges (simulating lightning).
    • Results: After a week, various amino acids (e.g., glycine, alanine), sugars, and other simple organic compounds were formed.
    • Conclusion: Demonstrated that organic molecules, essential building blocks for life, could be synthesized abiotically under conditions believed to exist on early Earth.
  • Microlightning: A phenomenon referring to tiny sparks that occur within water droplets, proposed by some recent studies as a potential energy source for the abiotic synthesis of organic molecules leading to the origin of life.

Speciation: Modes of speciation (allopatric, sympatric), reproductive isolation mechanisms.

  • Speciation: Evolutionary process leading to the formation of new and distinct species from ancestral ones.
  • Species Definition: A group of populations whose members can interbreed in nature and produce viable, fertile offspring.
  • Reproductive Isolation: The existence of biological factors (barriers) that prevent members of two species from interbreeding and producing viable, fertile offspring. This is central to the origin of new species.
  • Modes of Speciation:
    • Allopatric Speciation:
      • Occurs when populations are geographically separated by a physical barrier (e.g., mountain range, river, ocean).
      • Gene flow is interrupted, allowing separate populations to diverge independently due to mutation, natural selection, and genetic drift.
      • Reproductive isolation evolves as a byproduct of this divergence.
    • Sympatric Speciation:
      • Occurs in populations that live in the same geographic area; no physical barrier to gene flow.
      • Mechanisms leading to reproductive isolation within the same range:
      • Polyploidy: Presence of extra sets of chromosomes, especially common in plants, leading to immediate reproductive isolation.
      • Habitat Differentiation: Subpopulation exploits a new niche or resource (e.g., feeding on different host plants).
      • Sexual Selection: Nonrandom mate choice based on specific traits can lead to reproductive barriers.
  • Reproductive Isolation Mechanisms (Barriers to Gene Flow):
    • Pre-zygotic Barriers (prevent mating or fertilization from occurring):
      • Habitat Isolation: Species live in different habitats within the same geographic area.
      • Temporal Isolation: Species breed during different times (seasons, day/night).
      • Behavioral Isolation: Unique courtship rituals or signals prevent interspecies mating.
      • Mechanical Isolation: Morphological differences prevent successful completion of mating.
      • Gametic Isolation: Sperm of one species cannot fertilize eggs of another (e.g., incompatible receptors on gamete surfaces).
    • Post-zygotic Barriers (prevent hybrid zygote from developing into a viable, fertile adult):
      • Reduced Hybrid Viability: Hybrid offspring fail to develop or survive to adulthood.
      • Reduced Hybrid Fertility: Hybrid offspring are sterile (e.g., mules from horse and donkey).
      • Hybrid Breakdown: First-generation hybrids are viable and fertile, but subsequent generations become feeble or sterile.

Theories of Evolution: Lamarckism and Darwinism, their postulates and criticisms.

  • Theories of Evolution: Attempt to explain the mechanism of how life forms change over generations.
  • Lamarckism (Theory of Inheritance of Acquired Characters):
    • Propounded by Jean-Baptiste Lamarck in 1809 ("Philosophie Zoologique").
    • Postulates: Internal Vital Force: Organisms 1. constantly tend to increase in size. Environmental Influence & New 2. Needs: Changes in environment create new needs, leading to changes in habits/behavior. Use and Disuse of Organs: Or3. gans used more frequently develop better; disused organs degenerate or disappear (e.g., giraffe's long neck, loss of limbs in snakes). Inheritance of Acquired Charac4. ters: Characters acquired during an individual's lifetime (due to use/disuse or environmental influence) are passed on to offspring.
    • Criticisms:
      • Lack of scientific evidence for the inheritance of acquired characters.
      • August Weismann's germplasm theory disproved it: somatic changes are not inheritable (e.g., cutting mice tails for generations did not result in tailless offspring).
  • Darwinism (Theory of Natural Selection):
    • Propounded by Charles Darwin in 1859 ("On the Origin of Species by Means of Natural Selection").
    • Alfred Russel Wallace independently proposed similar ideas (co-discoverer).
    • Influences on Darwin & Wallace:
      • Thomas Robert Malthus's "An Essay on the Principle of Population" (1798): Highlighted the struggle for existence due to population growth outstripping resources.
      • Charles Lyell's geological studies (uniformitarianism).
      • Artificial selection in domestic animals.
    • Postulates (Key points of Natural Selection): Overproduction (Prodigality of 1. Production): Organisms produce more offspring than can survive. Struggle for Existence: Compet2. ition among individuals for limited resources, space, and mates. Variation and Heredity: Indi3. viduals within a population exhibit variations, some of which are heritable. Survival of the Fittest (Natural 4. Selection): Individuals with favorable heritable variations (adaptations) are better suited to their environment, survive longer, and reproduce more successfully. Nature "selects" these advantageous traits. Origin of New Species: Accumu5. lation of favorable variations over long periods, leading to divergence and the formation of new species.
    • Criticisms:
      • Did not explain the origin or mechanism of variations.
      • Did not explain how variations are inherited (Mendel's work on genetics was unknown to Darwin).
      • Overemphasized small, continuous variations, neglecting sudden, large changes (mutations).
      • Did not distinguish between somatic and germinal variations.
    • Modern Synthesis (Neo-Darwinism): Integrates Darwinian natural selection with Mendelian genetics, mutation theory, genetic drift, and gene flow to provide a more complete understanding of evolution.
  • Hugo de Vries: Associated with the Mutation Theory, which posits that evolution occurs through sudden, large, discontinuous heritable changes (mutations), providing the raw material for natural selection.

3. Taxonomy

Practice MCQs: Evolution of Life

Evidences for Evolution: Paleontological, comparative anatomy, embryological, molecular, biogeographical.

  1. Which one of the following animals is known as a 'living fossil'?

    Asked in: WBPSC CS Prelims 2022 · Economics & Statistical Officer Exam 2005

    1. Peripatus
    2. Amoeba
    3. Prawn
    4. Apple snail
    Show answer

    Answer: A. Peripatus

    A living fossil is an extant (living) species that appears to be similar to species otherwise only known from the fossil record, representing an ancient lineage that has survived with little morphological change over geological time. Peripatus belongs to the phylum Onychophora and exhibits B. Ethology C. Ethnography D. None of the above Ans: A Ethology is the science of animal behavior.

  2. NEET is an entrance examination for which of the following?

    Asked in: FINANCE AND ACCOUNTS OFFICER TREASURY OFFICER 2016

    1. B.Tech
    2. MBBS
    3. BDS
    4. b) and c)
    Show answer

    Answer: D. b) and c)

    NEET is a single entrance examination for admission to medical and dental colleges across India, covering both MBBS and BDS programs. traits linking annelids and arthropods, a very old evolutionary line.

  3. "Archaeopteryx" is connecting link between:

    Asked in: RPSC RAS Prelims 2008

    1. Amphibia and aves
    2. Reptiles and aves
    3. Reptiles and Mammals
    4. Aves and Mammals
    Show answer

    Answer: B. Reptiles and aves

    Archaeopteryx lithographica is considered a transitional fossil that exhibits characteristics of both non-avian feathered dinosaurs (often grouped under reptiles in evolutionary contexts) and birds (Aves). It possessed features like feathers and a wishbone (furcula) like birds, but also retained reptilian traits such as teeth, a long bony tail, and claws on its wings.

Human Evolution: Primate ancestry, hominid lineage, key evolutionary changes (bipedalism, brain size, tool use).

  1. mammoth is the ancestor of:

    Asked in: RPSC RAS Prelims 2008

    1. Dog
    2. Horse
    3. Camel
    4. Elephant
    Show answer

    Answer: D. Elephant

    Mammoths belong to the genus Mammuthus, while modern elephants belong to the genera Loxodonta (African elephants) and Elephas (Asian elephants). All three genera are part of the family Elephantidae.

  1. A tree species in Mauritius failed to reproduce because of the extinction of a fruit eating bird. Which one of the following was that bird?

    Asked in: UPPCS Prelims 1998

    1. Dove
    2. Dodo
    3. Condor
    4. Skua
    Show answer

    Answer: B. Dodo

    The Dodo bird played a crucial ecological role as a seed disperser and scarifier for certain native Mauritian plants, particularly the Calvaria major tree.

Mechanisms of Evolution: Mutation, recombination, gene flow, genetic drift (founder effect, bottleneck effect).

  1. The Mutation Theory of Evolution was enunciated by

    Asked in: UPPCS Prelims 2005

    1. Huxley
    2. Darwin
    3. Lamarck
    4. Hugo de Vries
    Show answer

    Answer: D. Hugo de Vries

    Hugo de Vries proposed that mutations are the source of new variations and can lead to the formation of new species.

Modern Synthetic Theory of Evolution (Neo-Darwinism): Genetic basis of variation, role of population genetics.

  1. Match List I with List II and select the correct answer using the codes given below the lists: List I List II A) Beadk and I. Theory of Mutation Tatum B) Jacob and II. Theory of Evolution Monod III. One gene one enzyme hy‐ C) Darwin pothesis IV. Operon concept D) De Vries Codes:

    Asked in: UPPCS Prelims 1998

    1. I-C, II-D, III-A, IV-B
    2. I-D, II-C, III-A, IV-B
    3. I-D, II-C, III-B, IV-A
    4. I-C, II-D, III-B, IV-A
    Show answer

    Answer: B. I-D, II-C, III-A, IV-B

    This question matches biological theories and concepts with the scientists associated with them. I. Theory of Mutation: Proposed by Hugo de Vries (D), based on his work with evening primroses. II. Theory of Evolution (by natural selection): Most famously articulated by Charles Darwin (C). III. One gene one enzyme hypothesis: Proposed by George Beadle and Edward Tatum (A), based on their experiments with Neurospora crassa, stating that each gene codes for a specific enzyme. IV. Operon concept: Proposed by François Jacob and Jacques Monod (B) in 1961, explaining the regulation of gene expression in bacteria, particularly the lac operon. Matching these gives: I-D, II-C, III-A, IV-B.

Natural Selection: Types (directional, stabilizing, disruptive), sexual selection, adaptive radiation.

  1. In the context of the organic evolution, the loss of limbs of snakes is explained by the phenomenon of

    Asked in: UPPCS Prelims 2002

    1. use and disuse of organs
    2. adaptation to living in burrows
    3. natural selection
    4. inheritance of acquired characters
    Show answer

    Answer: C. natural selection

    The loss of limbs in snakes during organic evolution is explained by the theory of natural selection. Over millions of years, ancestral snake populations likely contained individuals with variations in limb size and structure. In environments where a limbless or reduced-limb body plan was advantageous (e.g., for burrowing, slithering through vegetation, or moving through confined spaces), individuals with smaller or absent limbs were better suited for survival and reproduction. These individuals passed on their traits to offspring. Over successive generations, natural selection favoured those with reduced or absent limbs, leading to the complete loss of limbs in most snake species.

Origin of Life: Chemical evolution, abiogenesis, Oparin-Haldane hypothesis, Miller-Urey experiment.

  1. Miller-Urey hypothesized that lightning bolts in the ocean could have been the origin of life on the earth. A new study found that the process called microlightning may have sparked life on earth. Microlightning refers to

    Asked in: GS Asst Architect PWD 02 2025

    1. tiny sparks in water droplets
    2. frequent tiny lightning instead of a lightning bolt
    3. tiny sparks due to crashing of rocks
    4. tiny sparks in static electricity
    Show answer

    Answer: B. frequent tiny lightning instead of a lightning bolt

    The term "microlightning" in the context of the origin of life refers to frequent, smaller electrical discharges in the early Earth's atmosphere, which could have facilitated the synthesis of organic molecules.

Speciation: Modes of speciation (allopatric, sympatric), reproductive isolation mechanisms.

  1. Among living organisms, which one of the following is the most responsible factor for bringing about the origin of a new species?

    Asked in: UPPCS Prelims 2002

    1. Isolation
    2. Mutation
    3. Natural Selection
    4. Sexual Reproduction
    Show answer

    Answer: A. Isolation

    The origin of a new species, speciation, fundamentally requires the evolution of reproductive isolation between populations. For divergence to occur and lead to reproductive isolation, the populations need to stop exchanging genes freely. Isolation, particularly geographic isolation (allopatry), is often considered the most significant factor that initiates the process of speciation by preventing gene flow between populations. Once populations are isolated, they can diverge genetically due to mutation, genetic drift, and/or natural selection acting differently in their respective environments. This divergence can eventually lead to reproductive isolation.

Theories of Evolution: Lamarckism and Darwinism, their postulates and criticisms.

  1. Darwin and Wallace were both strongly influenced by the book "An Essay on the Principle of Population" written by

    Asked in: WBPSC CS Prelims 2016

    1. Erasmus
    2. Malthus
    3. Volterra
    4. Lamarck
    Show answer

    Answer: B. Malthus

    Both Charles Darwin and Alfred Russel Wallace independently developed the theory of evolution by natural selection. A key influence on their thinking was Thomas Malthus's 1798 essay, "An Essay on the Principle of Population". Malthus argued that populations tend to grow exponentially while resources grow arithmetically, leading to a struggle for existence, poverty, and famine. This concept of a 'struggle' for limited resources provided Darwin and Wallace with the crucial idea that individuals best adapted to their environment would be more likely to survive and reproduce.

  2. Who among the following is associated with the Law of Natural Selection?

    Asked in: J.E (Electrical 2020) 2020

    1. Mendel
    2. Dalton
    3. Kepler
    4. Darwin
    Show answer

    Answer: D. Darwin

    The Law of Natural Selection is attributed to Charles Darwin.