BIO NMDCAT

Lamarck believed in "phyletic transformation" rather than absolute extinction; he argued that species do not die out but continuously evolve into newer, more complex forms.

Lamarck's theory posits that environmental changes create new needs ("besoin") in an organism, which drives changes in habits, leading to the use or disuse of specific organs.

Lamarck's fourth postulate states that somatic modifications acquired during an organism's lifetime due to use/disuse are directly transmitted to the next generation.

The elongation of the giraffe's neck via stretching (use of organ) and subsequent inheritance of this stretched neck is the classic textbook example of Lamarckism (Inheritance of Acquired Characters).

August Weismann cut off the tails of mice for 22 consecutive generations. The offspring of the 23rd generation still developed normal tails, proving that somatic modifications (mutilations/acquired traits) are not inherited.

Weismann's Germplasm Theory states that only changes in the germ cells (germplasm) are transmitted to offspring, while somatic cells (somatoplasm) do not pass genetic info to the next generation.

Lamarck postulated that the continuous disuse of an organ leads to its gradual degeneration, reduction in size, and ultimate disappearance (vestigialization), as seen in the limbs of snakes.

Under Lamarckism, the continuous disuse of eyes in a dark cave environment leads to developmental decay, which is then inherited by subsequent generations.

Epigenetics involves study of heritable changes in gene function (like DNA methylation or histone modification) caused by environmental factors without altering the underlying DNA sequence, conceptually echoing Lamarck's environmental influence.

Lamarck's "Philosophie Zoologique" was published in 1809, which coincidentally was the year Charles Darwin was born.

"Besoin" refers to the inner need or urge felt by an organism when faced with environmental change, prompting it to alter its behavior and use certain organs more than others.

The colorful plumage of male peacocks is a product of sexual selection (Darwinian concept). Lamarck focused on physical adaptations gained through use (webbed feet, long wading legs) or disuse (limbless snakes).

Modern genetics shows that phenotype changes in somatic tissues (like muscle hypertrophy from working out) do not alter the DNA sequences of germ cells, making inheritance impossible.

Correct: Experiments support many aspects of chemical evolution, but the complete pathway is still being studied. A: Not fully reproduced. C: Incorrect. D: Chemical evolution remains widely accepted. Concept: Modern scientific understanding.

Correct: The finding supports the idea that organic compounds can form through natural chemical processes. B: Does not address Earth's origin specifically. C: Amino acids are not living cells. D: Proteins are formed from amino acids. Concept: Natural formation of organic molecules.

Correct: True living cells possess regulated metabolism and reproduce independently. A, C, D: These features may also occur in protocells. Concept: Characteristics of living cells.

Correct: The Miller-Urey experiment provided strong evidence that life's building blocks can form naturally under simulated primitive Earth conditions. A: Ignores the significance of prebiotic chemistry. C: No living organisms were produced. D: The experiment supports, rather than disproves, chemical evolution. Concept: Significance of the Miller-Urey experiment.

Correct: Abiogenesis concerns the first origin of life, while biogenesis applies to present-day reproduction. A, C, D: These incorrectly define the two concepts. Concept: Abiogenesis versus biogenesis.

Correct: Reducing gases favored the synthesis of organic compounds. A: Ozone developed later. C: Oxygen inhibits organic synthesis. D: Chlorofluorocarbons are modern pollutants. Concept: Primitive atmosphere.