Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.
Solution and Explanation
Top Questions on evolution
- How does the process of Natural Selection affect Hardy-Weinberg equilibrium? Explain with the help of graphs.
- (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?
Questions Asked in CBSE CLASS XII exam
- Two coils ‘1’ and ‘2’ are placed close to each other as shown in the figure. Find the direction of induced current in coil ‘1’ in each of the following situations, justifying your answers:
(a) Coil ‘2’ is moving towards coil ‘1’.
(b) Coil ‘2’ is moving away from coil ‘1’.
(c) The resistance connected with coil ‘2’ is increased keeping both the coils stationary.
- CBSE CLASS XII - 2025
- Electromagnetic induction
Bittu and Chintu were partners in a firm sharing profit and losses in the ratio of 4 : 3. Their Balance Sheet as at 31st March, 2024 was as follows:
On 1st April, 2024, Diya was admitted in the firm for \( \frac{1}{7} \)th share in the profits on the following terms:- (i) New profit sharing ratio between Bittu, Chintu and Diya was 3 : 3 : 1 .
- (ii) Fixed Assets were found to be overvalued by ₹ 1,40,000.
- (iii) Creditors were paid ₹ 4,20,000 in full settlement.
- (iv) Diya brought proportionate capital and ₹ 5,60,000 as her share of goodwill premium by cheque.
Prepare Revaluation Account and Partners' Capital Accounts.
- CBSE CLASS XII - 2025
- Partnership Accounts
- Pass the necessary journal entries for the following transactions on the dissolution of a partnership firm of Vibha and Ajit after various assets (other than cash) and external liabilities have been transferred to Realisation Account:}
Creditors worth ₹ 46,000 accepted ₹ 9,000 cash and furniture of ₹ 32,000 in full settlement of their claim.
The firm had stock of ₹ 20,000. Ajit took over 40% of the stock at a discount of 10% while the remaining stock was sold for ₹ 18,000.
Vibha was appointed to look after dissolution work for which she was allowed a remuneration of ₹ 16,000. Vibha agreed to bear the dissolution expenses. Actual dissolution expenses ₹ 15,000 were paid by Vibha.
Ajit’s loan of ₹ 45,000 was settled at ₹ 42,000.
A machine which was not recorded in the books was taken over by Vibha at ₹ 23,000, whereas its expected value was ₹ 28,000.
The firm had a debit balance of ₹ 20,000 in the Profit and Loss Account on the date of dissolution.- CBSE CLASS XII - 2025
- Dissolution of Partnership Firms
- A battery of emf \( E \) and internal resistance \( r \) is connected to a rheostat. When a current of 2A is drawn from the battery, the potential difference across the rheostat is 5V. The potential difference becomes 4V when a current of 4A is drawn from the battery. Calculate the value of \( E \) and \( r \).
- CBSE CLASS XII - 2025
- Current electricity
- An electric dipole of dipole moment \( 1.0 \times 10^{-12} \ \text{Cm} \) lies along the x-axis. An electric field of magnitude \( 2.0 \times 10^4 \ \text{NC}^{-1} \) is switched on at an instant in the region. The unit vector along the electric field is \( \frac{\sqrt{3}}{2} \hat{i} + \frac{1}{2} \hat{j} \). The magnitude of the torque acting on the dipole at that instant is:
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.