Class 12 Biology - KERALA
Evolution
The chapter Evolution in Class 12 Biology (Kerala SCERT) explores the fascinating story of how life originated and diversified on Earth. Students will study various theories of evolution, including Lamarckism and Darwinism, and understand modern synthetic theory. The chapter covers crucial evidence supporting evolution, such as paleontological, anatomical, and biochemical proofs. It also highlights human evolution, adaptive radiation, and mechanisms like genetic drift and natural selection. This chapter is vital for the Kerala Higher Secondary board exams as it consistently features conceptual questions, diagram-based evaluations on homologous and analogous organs, and numerical problems related to Hardy-Weinberg equilibrium.
Start Learning FreeKey Concepts
Origin of Life
Life originated from non-living organic molecules through chemical evolution, supported by the Miller-Urey experiment simulating primitive Earth conditions.
Evidences of Evolution
Fossils, comparative anatomy (homologous and analogous organs), and embryological studies provide concrete proof that organisms share common ancestors.
Darwin's Theory of Natural Selection
Organisms with advantageous traits are better adapted to their environment, survive, and reproduce, passing these beneficial traits to the next generation.
Hardy-Weinberg Principle
Allele frequencies in a population remain constant from generation to generation in the absence of evolutionary influences like selection, mutation, and migration.
Adaptive Radiation
The process of evolution of different species in a given geographical area starting from a point and radiating to other geographical areas, like Darwin's finches.
Human Evolution
Tracing the lineage of modern humans (Homo sapiens) from primate ancestors like Dryopithecus and Ramapithecus through Australopithecus and Homo erectus.
Important Formulas
Board Exam Info
In the Kerala SCERT Class 12 Biology board examinations, this chapter typically carries around 6 to 8 marks. Questions frequently include distinguishing between homologous and analogous organs, explaining the Hardy-Weinberg equilibrium with problems, describing Miller's experiment, and outlining the stages of human evolution.
Frequently Asked Questions
Homologous organs have the same structural origin and embryonic development but perform different functions (showing divergent evolution), whereas analogous organs perform similar functions but have different structural origins (showing convergent evolution).
Homologous organs have the same structural origin and embryonic development but perform different functions (divergent evolution), while analogous organs perform similar functions despite having different anatomical structures (convergent evolution).
It states that allele and genotype frequencies in a population remain constant from generation to generation in the absence of disturbing factors like mutation, genetic drift, gene flow, and natural selection.
It states that gene pool stability (allele frequencies) remains constant in a population over generations if evolutionary forces are absent.
Adaptive radiation involves multiple species diverging from a common ancestral point into various habitats, whereas convergent evolution involves unrelated species developing similar traits due to adapting to similar environments.
Adaptive radiation is the evolution of multiple species from a single ancestor in different habitats, while convergent evolution is when unrelated species develop similar adaptations due to similar environments.
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