Theories of Evolution
Lamarckism, Darwinian natural selection and modern synthetic theory. (Biology › Evolution, NEET UG syllabus.)
What is Theories of Evolution?
A theory of evolution proposing that organisms acquire characteristics during their lifetime through use or disuse and pass these acquired traits to their offspring.
Key points
- Differentiate between Lamarck's and Darwin's theories of evolution.
- Explain the key tenets of Darwin's theory of Natural Selection.
- Identify the limitations of classical Darwinism.
- Describe how the Modern Synthetic Theory addresses these limitations.
Common exam trap
Believing that acquired traits (e.g., a scar, developed muscles) can be inherited by offspring.
Definitions
- Term
Lamarckism
- Meaning
A theory of evolution proposing that organisms acquire characteristics during their lifetime through use or disuse and pass these acquired traits to their offspring.
- Term
Darwinism
- Meaning
The theory of evolution by natural selection, proposed by Charles Darwin, stating that advantageous variations enable individuals to survive and reproduce more successfully, leading to gradual changes in populations over generations.
- Term
Natural Selection
- Meaning
The process by which organisms better adapted to their environment tend to survive and produce more offspring, thereby increasing the frequency of advantageous traits in the population over time.
- Term
Inheritance of Acquired Characters
- Meaning
The discredited Lamarckian concept that traits developed during an organism's life (e.g., muscle development from exercise) can be passed on to its progeny.
- Term
Survival of the Fittest
- Meaning
A phrase coined by Herbert Spencer, adopted by Darwin, describing the differential survival and reproduction of individuals with advantageous traits that make them better suited to their environment.
- Term
Modern Synthetic Theory of Evolution
- Meaning
A comprehensive theory that combines Darwin's theory of natural selection with modern genetics, explaining evolution in terms of changes in gene frequencies within populations due to factors like mutation, recombination, natural selection, genetic drift, and gene flow.
Learning objectives
Differentiate between Lamarck's and Darwin's theories of evolution.
Explain the key tenets of Darwin's theory of Natural Selection.
Identify the limitations of classical Darwinism.
Describe how the Modern Synthetic Theory addresses these limitations.
Provide examples to illustrate the principles of each theory.
Prerequisites
Basic understanding of Mendelian genetics (genes, alleles, inheritance patterns).
Knowledge of DNA, mutations, and genetic recombination.
Familiarity with basic biological terms like species, population, phenotype, and genotype.
Common mistakes
Believing that acquired traits (e.g., a scar, developed muscles) can be inherited by offspring.
Confusing natural selection with a conscious effort or will of the organism to change.
Thinking that evolution occurs at the level of an individual rather than a population.
Not understanding that variation is random, but natural selection is directional.
Overlooking the role of genetic factors (mutation, recombination) in providing the raw material for evolution.
Keywords
Evolution
Lamarckism
Darwinism
Natural Selection
Variation
Adaptation
Inheritance of Acquired Characters
Survival of the Fittest
Modern Synthetic Theory
Mutation
Genetic Recombination
Genetic Drift
Gene Flow
Practice preview
Which of the following concepts is central to Lamarck's theory of evolution?…
easy
Which of the following sequences correctly represents the key steps in Darwin's theory of natural selection?…
medium
According to Darwin's theory of natural selection, what is the primary mechanism driving evolutionary change?…
easy