Science Group
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Unit-10 Evolution
Answer: Homologous organs share a common basic structure and origin but may perform different functions, like the forelimbs of mammals.
Answer: Adaptations accumulate over generations as natural selection favours individuals with beneficial variations.
Answer: Vestigial organs are reduced, non-functional remnants of organs that were functional in ancestral organisms.
Answer: Destruction of habitat removes the conditions needed for a species to survive, often leading to extinction.
Answer: Divergent evolution occurs when related species gradually become different as they adapt to different environments.
Answer: If a species cannot adapt to changes in its environment, its members die out and the species may become extinct.
Answer: The appendix is a vestigial organ in humans, a remnant of a larger organ used for digestion in plant-eating ancestors.
Answer: Fossil evidence indicates that human evolution began in Africa.
Answer: Homologous organs arise through divergent evolution from a common ancestor into different functions.
Answer: Molecular biology compares DNA sequences and proteins; greater similarity indicates closer evolutionary relationships.
Answer: Artificial selection is the intentional breeding by humans of organisms with desirable characteristics.
Answer: During human evolution, brain size increased greatly, enabling tool use, language, and complex thought.
Answer: Artificial selection is commonly called selective breeding because humans select which individuals breed.
Answer: Bipedalism, the ability to walk on two legs, was a major step in human evolution.
Answer: Analogous organs form through convergent evolution as unrelated organisms adapt to similar environments.
Answer: Galapagos finches evolved different beak shapes suited to different food sources, demonstrating natural selection.
Answer: In natural selection, the environment naturally selects organisms best suited to survive and reproduce.
Answer: During the Industrial Revolution, dark-coloured moths survived better on soot-darkened trees, showing natural selection.
Answer: Alfred Russel Wallace independently formulated the theory of natural selection and presented it jointly with Darwin.
Answer: Speciation is the evolutionary process by which new species arise from existing ones.