Which of the following statements is not true?
- Analogous structures are a result of convergent evolution
- Sweet potato and potato is an example of analogy
- Homology indicates common ancestry
- Flippers of penguins and dolphins are a pair of homologous organs
The Correct Option is D
Solution and Explanation
In order to determine which statement is not true, let's first understand the concepts of homologous and analogous structures. Homologous structures are body parts in different species that have a similar structure and position but differ in function, indicating a common ancestry. On the other hand, analogous structures perform similar functions but have different evolutionary origins, stemming from convergent evolution.
Let's evaluate each statement:
- Analogous structures are a result of convergent evolution: This statement is true. Convergent evolution leads to analogous structures because unrelated species develop similar traits independently due to adapting to similar environments.
- Sweet potato and potato is an example of analogy: This statement is also true. Although sweet potato and potato have similar functions (as storage organs), they have evolved independently in different plant species, making them analogous.
- Homology indicates common ancestry: True. Homologous structures share a common ancestor, differentiating this from analogy. Homology refers to similarities due to shared evolutionary lineage.
- Flippers of penguins and dolphins are a pair of homologous organs: This statement is not true. While flippers of penguins and dolphins have a similar function (swimming), they do not share a common evolutionary origin and are therefore considered analogous rather than homologous.
Thus, the statement, "Flippers of penguins and dolphins are a pair of homologous organs," is not true.
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.
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(ii) KCN
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- 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:
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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.