Practise drawing various animals and plants.
Solution and Explanation
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 CBSE CLASS XII exam
- ‘But the game he is watching so intently is out of his reach.’ What are the factors that have made their game inaccessible to Saheb? (Lost Spring)
- CBSE CLASS XII - 2025
- Literature
- The basic scheme of the essential steps involved in the process of recombinant DNA technology is summarised below in the form of a flow diagram. Study the given flow diagram and answer the questions that follow: \begin{center} Step-1 \quad Plasmid DNA (cut using Restriction Enzyme EcoR I) \quad + \quad Foreign DNA (cut using Restriction Enzyme EcoR I)
$\downarrow$
DNA ligase
$\downarrow$
Step-2 \quad Recombinant DNA molecule
$\downarrow$
Step-3 \quad Transfer of recombinant DNA molecule to the host cell
$\downarrow$
Step-4 \quad Replication of recombinant DNA molecule in the host cell \end{center} (a) Name the specific enzyme that might have been used to make the multiple copies of foreign DNA before undergoing Step-1 of the process.
(b) How does the use of restriction enzyme EcoR I in Step-1 facilitate the action of DNA ligase to form the recombinant DNA molecule? Explain.
(c) Name the most commonly used host in the above process.- CBSE CLASS XII - 2025
- Biotechnology
- Draft an invitation card on behalf of the Principal of J.B. Bhatia Public School for the launch of ‘Yoga for Life’ programme in the school. Mention a compelling highlight of the programme along with other necessary details.
- CBSE CLASS XII - 2025
- Letter Writing
- What is the difference between CRS and GDS?
- CBSE CLASS XII - 2025
- Hotel Operations
- What is the significance of reservation to the guest?
- CBSE CLASS XII - 2025
- Hotel Operations
Concepts Used:
Evidence for Evolution
Evolution evidence is one of the most important pillars of current biological theory. It is the only way to prove all of the proposed evolution theories. Fossils, comparative anatomy, and embryo development patterns are among the evidence used to support biological evolution.
Fossils are the non-degraded remains of living organisms discovered within rocks. The age of the fossil is determined by the layer in which it was recovered. In comparison to the fossils found in the upper layers, those found farther down are older. They provide insight on the condition of the specific region. Palaeontology is the scientific study of fossils.
Comparative Anatomy describes how many organisms share an origin and how natural selection or genetic drift led to the evolution of many diverse organisms. There were two categories of comparative anatomy found: homologous organs and analogous organs.
In Embryonic Development, until a certain stage of gestation, the embryos of various species have a similar structure. Human embryos, pig embryos, reptile embryos, and bird embryos, for instance, have similar embryonic development. As they grow older, they transform into the appropriate species. This demonstrates common ancestry once again.