Read the following passage and answer the questions that follow. The most convincing evidence to trace evolutionary relationships between humans and different groups of animals come from the basic similarities seen at the molecular level. Study the table given below that depicts the number of amino acid differences between the haemoglobin polypeptide of few animals with that of humans and answer the questions that follow.
| S.No. | Animal | No. of amino acid differences in haemoglobin with that of humans |
|---|---|---|
| 1. | Macaque | 08 |
| 2. | Dog | 32 |
| 3. | Bird | 45 |
| 4. | Frog | 67 |
| 5. | Lamprey | 125 |
(a) To which category of evolution (Divergent or Convergent) do the following evolutionary relationships belong to : (i) Humans and Macaque (ii) Humans and Frog (b) What do the biochemical similarities in haemoglobin suggest about the evolutionary relationship between humans, frog and lamprey ? (c) (i) Which one of the two – lampreys' or macaques' evolution is more closely related to humans and why ? OR (c) (ii) Which one of the two – frogs' or dogs' evolution is more closely related to humans and why ?
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🔒 Start your 14-day free trial to unlock the full solution →Part (a)Concept understanding — Human Evolution Evidence
Human Evolution Evidence: A First Look
Think about a detective who arrives at a crime scene long after everyone has left. There are no eyewitnesses, no videos, no confessions. Yet the detective can piece together what happened — from footprints, a strand of hair, a broken cup, the pattern of dust on the floor. That is exactly how scientists study human evolution. We cannot go back in time to watch our ancestors evolve, but we have left behind clues. The job of an evolutionary scientist is to read those clues.
What is human evolution evidence?
Human evolution evidence is any physical or biological trace left by our ancestors that helps us understand how modern humans — Homo sapiens — came to be. It is not a single thing. It is a collection of different kinds of clues that, when put together, tell a story spanning millions of years.
The NCERT textbook for Class 12 (Biology, Chapter 7) introduces this topic under "Evolution" and emphasises that the evidence comes from fossils, comparative anatomy, embryology, and molecular biology. For a humanities or commerce student, the key is to see these as different types of documents in the archive of life.
The main types of evidence
1. Fossils — the direct remains
Fossils are the most dramatic evidence. They are the preserved remains of ancient organisms — bones, teeth, footprints, even impressions of skin or feathers. When a hominid (an early human relative) died and was quickly buried by sediment, its bones could slowly turn to stone over millions of years.
What do fossils tell us? They show us the shape of the skull, the size of the brain, the structure of the jaw and teeth, and whether the creature walked upright. For example, the famous fossil "Lucy" (Australopithecus afarensis) from Ethiopia, dated to about 3.2 million years ago, had a small brain but walked on two legs. That was a revolutionary clue: bipedalism (walking on two feet) came before a large brain.
Fossils are rare. Most organisms never become fossils. The ones we find are a tiny, incomplete sample. This is why every new fossil discovery can rewrite parts of the story.
2. Comparative anatomy — the body's blueprint
If you look at the bones of a human arm, a bat's wing, a whale's flipper, and a horse's leg, you will notice something striking: they all have the same basic arrangement of bones — one upper bone, two lower bones, a cluster of wrist bones, and then digits. These are called homologous organs — same structure, different functions.
Why does this matter? It suggests that all these animals inherited this basic limb plan from a common ancestor. Over millions of years, natural selection modified the same blueprint for different uses — flying, swimming, running, grasping. The NCERT textbook uses this as a key argument for evolution: similar structures in different species point to a shared ancestry.
Do not confuse homologous organs with analogous organs — structures that look similar but have different evolutionary origins, like the wings of a bird and the wings of an insect. They serve the same function (flying) but evolved independently. That is convergent evolution, not common ancestry.
3. Embryology — the shared beginning
In the early stages of development, the embryos of fish, amphibians, reptiles, birds, and mammals look remarkably alike. All have a tail, gill slits, and a similar body plan. As development proceeds, they diverge into their distinct adult forms.
This similarity in early embryos is evidence that these groups share a common ancestor. The NCERT textbook mentions this as "embryological evidence" — the idea that the more closely related two species are, the longer their embryos will resemble each other.
4. Molecular biology — the DNA record
This is the most modern and precise type of evidence. Every living organism uses DNA as its genetic material. By comparing the DNA sequences of different species, scientists can measure how closely related they are. Humans and chimpanzees share about 98–99% of their DNA. Humans and mice share about 85%. Humans and bacteria share far less.
The NCERT textbook points out that molecular evidence has confirmed what fossils and anatomy had already suggested: humans are most closely related to the great apes (chimpanzees, gorillas, orangutans), and our evolutionary path split from the chimpanzee lineage roughly 6–7 million years ago.
Why does this evidence matter? …
Part (b)Concept understanding — Human Evolution Evidence
Human Evolution Evidence: A First Look
Think about a detective who arrives at a crime scene long after everyone has left. There are no eyewitnesses, no videos, no confessions. Yet the detective can piece together what happened — from footprints, a strand of hair, a broken cup, the pattern of dust on the floor. That is exactly how scientists study human evolution. We cannot go back in time to watch our ancestors evolve, but we have left behind clues. The job of an evolutionary scientist is to read those clues.
What is human evolution evidence?
Human evolution evidence is any physical or biological trace left by our ancestors that helps us understand how modern humans — Homo sapiens — came to be. It is not a single thing. It is a collection of different kinds of clues that, when put together, tell a story spanning millions of years.
The NCERT textbook for Class 12 (Biology, Chapter 7) introduces this topic under "Evolution" and emphasises that the evidence comes from fossils, comparative anatomy, embryology, and molecular biology. For a humanities or commerce student, the key is to see these as different types of documents in the archive of life.
The main types of evidence
1. Fossils — the direct remains
Fossils are the most dramatic evidence. They are the preserved remains of ancient organisms — bones, teeth, footprints, even impressions of skin or feathers. When a hominid (an early human relative) died and was quickly buried by sediment, its bones could slowly turn to stone over millions of years.
What do fossils tell us? They show us the shape of the skull, the size of the brain, the structure of the jaw and teeth, and whether the creature walked upright. For example, the famous fossil "Lucy" (Australopithecus afarensis) from Ethiopia, dated to about 3.2 million years ago, had a small brain but walked on two legs. That was a revolutionary clue: bipedalism (walking on two feet) came before a large brain.
Fossils are rare. Most organisms never become fossils. The ones we find are a tiny, incomplete sample. This is why every new fossil discovery can rewrite parts of the story.
2. Comparative anatomy — the body's blueprint
If you look at the bones of a human arm, a bat's wing, a whale's flipper, and a horse's leg, you will notice something striking: they all have the same basic arrangement of bones — one upper bone, two lower bones, a cluster of wrist bones, and then digits. These are called homologous organs — same structure, different functions.
Why does this matter? It suggests that all these animals inherited this basic limb plan from a common ancestor. Over millions of years, natural selection modified the same blueprint for different uses — flying, swimming, running, grasping. The NCERT textbook uses this as a key argument for evolution: similar structures in different species point to a shared ancestry.
Do not confuse homologous organs with analogous organs — structures that look similar but have different evolutionary origins, like the wings of a bird and the wings of an insect. They serve the same function (flying) but evolved independently. That is convergent evolution, not common ancestry.
3. Embryology — the shared beginning
In the early stages of development, the embryos of fish, amphibians, reptiles, birds, and mammals look remarkably alike. All have a tail, gill slits, and a similar body plan. As development proceeds, they diverge into their distinct adult forms.
This similarity in early embryos is evidence that these groups share a common ancestor. The NCERT textbook mentions this as "embryological evidence" — the idea that the more closely related two species are, the longer their embryos will resemble each other.
4. Molecular biology — the DNA record
This is the most modern and precise type of evidence. Every living organism uses DNA as its genetic material. By comparing the DNA sequences of different species, scientists can measure how closely related they are. Humans and chimpanzees share about 98–99% of their DNA. Humans and mice share about 85%. Humans and bacteria share far less.
The NCERT textbook points out that molecular evidence has confirmed what fossils and anatomy had already suggested: humans are most closely related to the great apes (chimpanzees, gorillas, orangutans), and our evolutionary path split from the chimpanzee lineage roughly 6–7 million years ago.
Why does this evidence matter? …
Haemoglobin is a homologous protein; the number of amino-acid differences from human haemoglobin measures evolutionary distance — fewer differences mean a more recent common ancestor. Data: Macaque 8, Dog 32, Bird 45, Frog 67, Lamprey 125.
Part (a)
- Type of evolution. (i) Humans and Macaque and (ii) Humans and Frog are both divergent evolution — all possess the homologous protein haemoglobin inherited from a common ancestor, and their sequences have diverged over time (the differences merely reflect how long ago they split).
- What the similarities suggest for human, frog and lamprey. The shared presence of haemoglobin shows all three descend from a common ancestor. The number of differences reveals the timing: frog (67) is closer to humans than lamprey (125), so the lamprey lineage diverged from the human line earliest, then the frog, indicating decreasing relatedness in the order human → frog → lamprey. …
Part (a): both human–macaque and human–frog relationships are divergent evolution; haemoglobin similarity shows human, frog and lamprey share a common ancestor (lamprey diverged earliest); the macaque (8 differences) is far more closely related to humans than the lamprey (125).
Part (c): the dog (32 differences) is more closely related to humans than the frog (67).
Homologous proteins such as haemoglobin serve as molecular evidence of evolution: mutations accumulate over time, so the fewer the amino-acid differences between two species' haemoglobin, the more recently they shared a common ancestor.
Part (a)
(a) Divergent or convergent. The presence of the same homologous protein, haemoglobin, in all these animals is the hallmark of divergent evolution — descent from a common ancestor with subsequent accumulation of differences.
- (i) Humans and Macaque: divergent (only 8 differences → very recent common ancestor).
- (ii) Humans and Frog: divergent (67 differences → a much older common ancestor, but still shared). Convergent evolution would require the protein to have arisen independently, which is not the case for such a conserved molecule.
(b) Human, frog and lamprey. The biochemical similarity of haemoglobin in all three means they possess a common evolutionary ancestor from which the protein was inherited. The differences date their splits: human–frog = 67, human–lamprey = 125. Thus the lamprey lineage separated from the human line earliest (most differences), the frog later, so relatedness to humans decreases in the order human → frog → lamprey. …
Showing the 12 most recent of 21 on this concept.
- CBSE 2026Set V11 markQ.Homo erectus had a brain size around ___________.
›Reveal solutionSolution
Homo erectus had a brain capacity of about 900 cc.
In human evolution, Homo erectus lived about 1.5 million years ago and had a larger brain than its ancestors, with a cranial (brain) capacity of around 900 cc. Homo erectus probably ate meat. (For comparison, Ho …
- CBSE 2026Set A1 markMCQQ.Which of the following was more like ape?(a) Dryopithecus(b) Ramapithecus(c) Homo erectus(d) Australopithecus
›Reveal solutionSolution
Among these ancestors, Dryopithecus was the most ape-like; Ramapithecus was more man-like.
Dryopithecus was a hairy, ape-like primate that walked like a gorilla/chimpanzee and is regarded as more ape-like. Ramapithecus was more man-like (more human). Australopithecus and Homo erectus are l …
- CBSE 2026Set ANNUAL1 markQ.Fill in the blank: The brain capacity of homo habilis man was ______ cc.
›Reveal solutionSolution
Homo habilis, the first tool-using early human, had a cranial (brain) capacity of roughly 650-800 cc.
Fossils of Homo habilis, discovered in Africa, show a brain capacity of about 650 to 800 cubic centimetres (cc) - larger than earlier hominids like Australopithecus but smaller than modern Homo sapiens (~1350 …
- CBSE 2026Set ANNUAL1 markQ.Fill in the blank: Homo sapiens arose in ______ and moved across continents.
›Reveal solutionSolution
Homo sapiens arose in Africa and spread to other continents.
According to the accepted account of human evolution, modern humans (Homo sapiens) first appeared in Africa. From there they moved out and gradually spread across the different continents of the world, adapting …
- CBSE 2025Set 57/4/11 markMCQQ.About 15 mya during human evolution, the primates which used to walk like gorillas and chimpanzees were : (A) Australopithecine and Neanderthal (B) Dryopithecus and Ramapithecus (C) Homo erectus and Homo sapiens (D) Homo habilis and Homo erectus
›Reveal solutionSolution
The primates that walked like gorillas and chimpanzees about 15 million years ago were Dryopithecus and Ramapithecus — the correct option is (B).
The key to this question is understanding the timeline of human evolution. About 15 million years ago (mya), we are looking at the Miocene epoch, long before the genus Homo appeared. The walking style described — like gorillas and chimpanzees — refers to quadrupedal knuckle-walking, not bipedalism. So we need to identify which early apes from that era moved in that manner.
Let’s break down the options:
-
Option (A): Australopithecine and Neanderthal
- Australopithecines lived around 4–2 mya, not 15 mya. They were bipedal (walked upright), not knuckle-walkers.
- Neanderthals (Homo neanderthalensis) appeared much later, around 400,000–40,000 years ago, and were fully bipedal.
- So this is wrong on both timing and locomotion.
-
Option (B): Dryopithecus and Ramapithecus
- Dryopithecus lived about 15–8 mya in Europe and Africa. It was a tree-dwelling ape with a quadrupedal, knuckle-walking style, similar to modern great apes.
- Ramapithecus (now often considered a female Sivapithecus) lived around 14–8 mya in Asia. It also moved on all fours, with a body plan like that of chimpanzees or gorillas.
- Both fit the time frame and the walking style. This is the correct pair.
-
Option (C): Homo erectus and Homo sapiens
- Homo erectus appeared around 1.8 mya, and Homo sapiens around 300,000 years ago. Both are fully bipedal.
- Far too recent and the wrong gait. …
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- CBSE 2025Set F1 markMCQQ.Which of the following is a significant trend in human evolution?(a) Upright posture(b) Binocular vision(c) Increasing cranial capacity(d) All of these
›Reveal solutionSolution
Human evolution shows upright posture, binocular vision and a steadily increasing brain (cranial) capacity — all of these.
Key trends from ape-like ancestors to modern Homo sapiens include:
- Erect/upright bipedal posture (freeing the hands),
- Forward-facing eyes giving binocular, stereoscopic vision (depth perception), …
- CBSE 2025Set ANNUAL1 markMCQQ.The following are some of the well-known fossils in the evolution of modern man : • Homo habilis • Homo erectus • Homo sapiens • Australopithecus The correct sequence of their origin is :(a) Homo habilis - Homo erectus - Homo sapiens - Australopithecus(b) Australopithecus - Homo habilis - Homo erectus - Homo sapiens(c) Homo habilis - Australopithecus - Homo erectus - Homo sapiens(d) Australopithecus - Homo erectus - Homo habilis - Homo sapiens
›Reveal solutionSolution
Human evolution proceeded from early small-brained hominids to modern humans in the order: Australopithecus, then Homo habilis, then Homo erectus, then Homo sapiens.
The broadly accepted fossil sequence in the evolution of modern humans is:
- Australopithecus (~2 million years ago, in East African grasslands) — likely hunted with stone weapons but mainly ate fruit.
- Homo habilis (~2 million years ago, brain capacity ~650–800 cc) — did not eat meat, generally regarded as the first 'handy man', tool-using.
- Homo erectus (~1.5 million years ago, brain size ~900 cc) — ate meat, e.g. Java man. …
- CBSE 2024Set E1 markMCQQ.When did pre-historic cave art develop?(a) 18,000 years ago(b) 10,000 years ago(c) 75,000 years ago(d) 40,000 years ago
›Reveal solutionSolution
Pre-historic cave (rock) art developed about 18,000 years ago.
During human evolution, modern Homo sapiens arose in Africa and spread across continents. As part of the account of human cultural development, pre-historic cave art (rock paintings, such as those at Bhimbetka) developed about 18,000 years ago. Agriculture came around 10,000 y …
- CBSE 2024Set ANNUAL1 markQ.What was the approximately brain size of Homo erectus man?
›Reveal solutionSolution
Homo erectus, who lived roughly 1.5 million years ago, had an estimated cranial (brain) capacity of about 900 cc.
According to the fossil evidence discussed in the account of human evolution, Homo erectus lived around 1.5 million years ago and had a brain capacity of approximately 900 cc, larger than earlier …
- CBSE 2024Set ANNUAL1 markMCQQ.Modern human, Homo sapiens arose during ice age between(a) 1,00,000 - 40,000 years ago(b) 75,000 - 10,000 years ago(c) 18,000 years ago(d) 10,000 years ago
›Reveal solutionSolution
Modern Homo sapiens arose probably in Africa and moved across continents, reaching as far as Java and China, roughly 75,000 to 10,000 years ago, near the end of the last ice age.
The fossil record of human evolution places different hominid stages at different times: Australopithecines (~2 million years ago, ate fruit, walked upright), Homo habilis (~2 million years ago, first tool-using hominid), Homo erectus (~1.7 million years ago), Neanderthal man (~1,00,000-40,000 years ago, large brain of ~1400 cc, used hide …
- CBSE 2023Set ANNUAL1 markMCQQ.According to Binomial system, what is the biological name of modern human -(a) Homo-sapiens(b) Panthera tigris(c) Homo-erectus(d) Homo-habilis
›Reveal solutionSolution
Modern humans are scientifically named Homo sapiens under the binomial system.
Under the binomial nomenclature system (Linnaeus), every organism is given a two-part name comprising its genus followed by its species. Modern humans belong to genus Homo and species sapiens, so their correct biological name is Homo sapiens. Panthera tigris is the tiger; H …
- CBSE 2023Set ANNUAL1 markMCQQ.The brain capacity of the Neanderthal man was(a) 650 - 800 cc(b) 900 cc(c) 1400 cc(d) 300 cc
›Reveal solutionSolution
Neanderthal man (Homo neanderthalensis), a robust, cold-adapted hominin that lived roughly 1,00,000 to 40,000 years ago, had a brain capacity of about 1400 cc.
In the fossil record of human evolution, brain capacity increased progressively: early hominins/Australopithecus had small brains (roughly 300–500 cc), Homo habilis (the option '650–800 cc') and Homo erectus (the option '900 cc') show intermediate increases, while Neanderthal man reached about 1400 cc — close to, a …
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