Darwin in his Natural Selection Theory did not believe in any role of which one of the following in organic evolution:
- Parasites and predators as natural enemies
- Survival of the fittest
- Struggle for existence
- Discontinuous variations
The Correct Option is D
Solution and Explanation
Darwin primarily focused on continuous variations and gradual changes in traits as a result of natural selection. He proposed that small, incremental variations within populations could lead to the evolution of new species over long periods of time. Discontinuous variations, on the other hand, involve abrupt, distinct changes in traits, and they were not a central part of Darwin's theory of evolution through natural selection.
So, the correct option is (D): Discontinuous variations
Top Questions on evolution
- (a) “The process of evolution of different species in a given geographical area starts from a point and literally radiates to other geographical areas.” Explain it with an example.
(b) Cite an example where more than one adaptive radiation has occurred in an isolated geographical area. Name the type of evolution your example depicts. - (a) "The process of evolution of different species in a given geographical area starts from a point and literally radiates to other geographical areas." Explain it with an example.
(b) Cite an example where more than one adaptive radiation has occurred in an isolated geographical area. Name the type of evolution your example depicts. - A few stages and their respective time period in the evolutionary history of human beings are mentioned in the flowchart given below:
- 15 mya — Primates walking like gorillas and chimpanzees existed.
- 3–4 mya — Man-like primates walked in Eastern Africa. Fossils of their bones were discovered.
- 2 mya — This ancestor lived in the East African grasslands and ate fruits.
- 1.5 mya — This hominid had a brain size of 900 cc and probably ate meat.
- [(a)] Name one primate about 15 mya.
- [(b)] Name one place where fossils of primates were discovered in Eastern Africa.
- [(c)] Name the ancestor that lived in the East African grasslands about 2 mya.
- [(d)] Name the hominid that was found around 1.5 mya.
The given graph shows the range of variation among population members, for a trait determined by multiple genes. If this population is subjected to disruptive selection for several generations, which of the following distributions is most likely to result?
Read the following passage and answer the questions that follow. According to evolutionary theory, every evolutionary change involves the substitution of a new gene for the old one and the new allele arises from the old one. Continuous accumulation of changes in the DNA coding for proteins leads to evolutionary differences. The chemical composition of DNA is basically the same in all living beings, except for differences in the sequence of nitrogenous bases. Given below are percentage relative similarities between human DNA and DNA of other vertebrates:
(a) What is the term used for the substitution of a new gene for the old one and the new allele arising from the old one during evolutionary process?
(b) Which one of the following holds true for the data provided in the above table?
- [(A)] Greater the evolutionary distance, greater are the differences in the nitrogenous bases.
- [(B)] Lesser the evolutionary distance, greater are the differences in the nitrogenous bases.
- [(C)] Greater the evolutionary distance, lesser are the differences in the nitrogenous bases.
- [(D)] Lesser the evolutionary distance, lesser are the differences in the nitrogenous bases.
(c) [(i)] To which category of evolution (divergent or convergent) does the following relationship belong? Justify your answer.
Human and Rhesus Monkey
OR[(ii)] Differentiate between Convergent and Divergent evolution.
Questions Asked in NEET exam
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
- NEET (UG) - 2025
- Moment Of Inertia
Predict the major product $ P $ in the following sequence of reactions:
(i) HBr, benzoyl peroxide
(ii) KCN
(iii) Na(Hg), $C_{2}H_{5}OH$- NEET (UG) - 2025
- Organic Chemistry
AB is a part of an electrical circuit (see figure). The potential difference \(V_A - V_B\), at the instant when current \(i = 2\) A and is increasing at a rate of 1 amp/second is:
- NEET (UG) - 2025
- Electromagnetic Induction and Inductance
- A wire of resistance \(R\) is cut into 8 equal pieces. From these pieces, two equivalent resistances are made by adding four of these together in parallel. Then these two are added in series. The net effective resistance of the combination is:
- NEET (UG) - 2025
- Resistance
- Consider the diameter of a spherical object being measured with the help of a Vernier Callipers. Suppose its 10 Vernier Scale Divisions (V.S.D.) are equal to its 9 Main Scale Divisions (M.S.D.). The least count in the M.S. is 0.1 cm and the zero of V.S. is at -0.1 cm when the jaws of Vernier callipers are closed. If the main scale reading for the diameter is \(M = 5\) cm and the number of coinciding vernier division is 8, the measured diameter after zero error correction, is:
- NEET (UG) - 2025
- Measurement of length
Concepts Used:
Evolution
Evolution is a process that occurs in changes in the genetic content of a population over time. Evolutionary change is generally classified into two: microevolution and macroevolution. The process of changes in allele frequencies in a population over time is a microevolutionary process. Three main mechanisms that cause allele frequency change are natural selection, genetic drift, and gene flow. On the other hand, macroevolution refers to change at or above the level of the species.