Evolutionary Biology

The term 'hot dilute soup' was coined by J.B.S. Haldane to describe the primordial environment where organic molecules formed, which is a central concept in the theory of chemical evolution (Oparin-Haldane hypothesis).

Sickle cell trait provides a survival advantage against malaria in heterozygous individuals. This balanced polymorphism keeps the sickle cell gene in the population despite the lethality of the homozygous condition.

Homo erectus is widely considered a direct ancestor of modern humans (Homo sapiens). Neanderthals are a separate lineage, and Australopithecus is an early hominin ancestor but not the direct ancestor in the same sense as Homo erectus.

Sibling species are populations that are morphologically very similar or identical but are reproductively isolated from each other. They often exist in the same geographic area (sympatric).

According to Darwinism, the sequence is: (D) Struggle for existence, (B) Variations and their inheritance, (C) Survival of the fittest, and (A) Natural selection. This leads to the adaptation of the population.

The melanization of the Peppered Moth is a classic example of natural selection acting on existing genetic variation, not the inheritance of acquired characters as proposed by Lamarck.

Correct matches: African ape man (Australopithecus), Java ape man (Pithecanthropus), Peking man (Sinanthropus), and Neanderthal (Homo).

The gene pool is defined as the sum total of all genes and their alleles present in a population at any given time.

Correct matches: Latimeria (Living fossil), Archaeopteryx (Connecting link), HMS Beagle (Charles Darwin), and Evening primrose (Mutation theory - Hugo de Vries).

Thomas Malthus wrote 'An Essay on the Principle of Population', which proposed that populations grow geometrically while food supplies grow arithmetically. This influenced Darwin's concept of the struggle for existence.

The chronological order of these hominids is: (d) Australopithecus, (b) Homo erectus, (a) Neanderthal, and (c) Cro-Magnon.

According to Lamarckism, long necked giraffes evolved because of stretching of necks by short ones over many generations. 

August Weismann's experiment with mice tails demonstrated that physical changes acquired during an organism's life are not passed on to offspring, thereby refuting Lamarck's theory of inheritance of acquired characters.

Natural selection is the fundamental mechanism proposed by Charles Darwin to explain how evolution occurs and how species adapt to their environments.

'Philosophie Zoologique' was published in 1809 by Jean-Baptiste Lamarck, outlining his theory of evolution.

While Darwin popularized the concept, the phrase 'survival of the fittest' was coined by Herbert Spencer after reading Darwin's work.

Homo habilis, meaning 'handy man' or 'tool maker', was named for the stone tools found in association with its fossils.

Genetic drift is the change in the frequency of an existing gene variant (allele) in a population due to random sampling of organisms. It is most pronounced in small populations.

Correct matches: First reptiles (Pennsylvanian), First amphibians (Devonian), First dinosaurs (Triassic), and First fishes (Ordovician).

Wings of a grasshopper and wings of a pigeon are analogous structures (different origin, same function). The other options (bat/bird wings, whale flipper/human hand, human testis/ovaries) are homologous structures (same origin, different function).

Hybrid breakdown is a post-zygotic reproductive isolation mechanism where the first-generation hybrids are viable and fertile, but the subsequent generations (F2 or backcrosses) are feeble or sterile. This prevents gene flow between the two parent species.

Archaeopteryx is widely recognized as a classic missing link (transitional fossil) between non-avian dinosaurs and birds, possessing features of both groups. Peripatus is a link between Annelida and Arthropoda, not a missing link in the same sense.

While many associate evolution with Darwin or Lamarck, the Greek philosopher Empedocles is credited with the earliest recorded ideas regarding the transmutation of species and the survival of the fittest, long before modern evolutionary theory.

Neopilina is a monoplacophoran mollusk that exhibits segmented body structures, which is a characteristic feature of annelids. Therefore, it serves as a connecting link between the phyla Annelida and Mollusca.

According to the principles of natural selection, alleles that provide a fitness advantage to the organism in a given environment are more likely to be passed on to the next generation, thus increasing their frequency in the population.

Sympatric speciation, the formation of new species within the same geographic area, is most common in plants, often through polyploidy (a change in chromosome number).

Linnaeus is known for the binomial nomenclature system and the concept of species as fixed and immutable entities, not dynamic ones. The other pairings correctly describe their respective evolutionary concepts.

Phylogeny refers to the evolutionary development and diversification of a species or group of organisms, often represented as a tree showing ancestral relationships.

The Mesozoic era is divided into three periods: the Triassic (earliest), followed by the Jurassic, and ending with the Cretaceous (latest).

By definition, a species is a group of interbreeding populations that are reproductively isolated from other such groups. Gene flow is a defining characteristic that maintains the cohesion of a species, so stating it does not occur is incorrect.

Parallel evolution occurs when two related or similar species evolve independently in similar environments, acquiring similar adaptations. The Tasmanian wolf and the placental wolf are classic examples of this phenomenon.

The emergence of pesticide resistance in insects is a direct observation of natural selection in action, where individuals with a random mutation that confers resistance survive and reproduce, passing the trait to offspring.

Ammonites are an extinct group of marine invertebrate animals in the subclass Ammonoidea of the class Cephalopoda. They are closely related to modern octopuses, squids, and cuttlefish.

Homologous organs share a common evolutionary origin and underlying structure, even if they perform different functions. The fins of a seal, wings of a bird, and human forelimbs all share the same pentadactyl limb structure.