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EvolutionNEET Zoology · Class 12 · NCERT Chapter 6

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3 interactive concept widgets for Evolution. Drag any slider, change any number, and watch the formula and the answer update live. Built so you understand how each NEET problem actually works, not just the final number.

On this page

Fossil, anatomical and molecular evidence
Allele and genotype frequency calculator
Dryopithecus to Homo sapiens

Evidence for evolution

Explore the types of evidence for evolution: fossils, homologous and analogous organs, vestigial organs, embryology and molecular evidence.

Evidence for evolution

Evidence for evolution: click any type to explore

Six types of evidence for evolution: fossil, homologous organs, analogous organs, vestigial organs, embryological, and molecular. Select one to see what it is, a key example, and what it proves about evolutionary relationships.

Fossil Evidence
Homologous Organs
Analogous Organs
Vestigial Organs
Embryological Evidence
Molecular Evidence

Homologous Organs

What it is

Homologous organs are structurally similar (same bones, same embryonic origin) but functionally different in different organisms. They show divergent evolution: a common ancestor gave rise to different species adapted to different environments.

Example

The forelimbs of humans (grasping), whales (swimming), bats (flying), and horses (running). All have the same humerus-radius-ulna-carpals-phalanges arrangement, but each is modified for a different function.

What it proves

Divergent evolution from a common ancestor. All four organisms descended from the same tetrapod ancestor, then evolved different functions for the same basic limb structure.

NEET fact

Homologous = same structure, different function = divergent evolution = common ancestry. The forelimb example is the most tested in NEET.

Divergent evolution

Common ancestor → different species. Evidence: homologous organs. Same structure, different function.

Convergent evolution

Different ancestors → similar adaptations. Evidence: analogous organs. Different structure, same function.

Try this

  • Click "Homologous Organs" and "Analogous Organs" one after the other. Can you explain in one sentence why homologous organs prove common ancestry but analogous organs do not?
  • Which type of evidence gives the most precise measure of how closely two species are related? (Hint: think about sequences.)
  • Vestigial organs are non-functional. If natural selection removes harmful traits, why do vestigial organs still exist in humans?

Hardy-Weinberg calculator

Drag the allele frequency and watch the genotype frequencies p squared, 2pq and q squared update live.

Hardy-Weinberg principle

Hardy-Weinberg calculator: slide p to see genotype frequencies

Set the dominant allele frequency (p) using the slider or a preset. The widget instantly computes q, then p², 2pq, and q² and shows the three genotype frequencies as a stacked bar chart. Use it to solve NEET Hardy-Weinberg problems.

p + q = 1    p² + 2pq + q² = 1

p = frequency of dominant allele (A)  |  q = frequency of recessive allele (a)

Quick presets

p = 0.9, q = 0.1
p = 0.7, q = 0.3
p = 0.5, q = 0.5
p = 0.6, q = 0.4
p = 0.2, q = 0.8

Frequency of allele A (p)

p = 0.60

p = 0 (only a)

p = 1 (only A)

Genotype frequency distribution

36.0%

48.0%

16.0%

p² (AA) = 36.00%

2pq (Aa) = 48.00%

q² (aa) = 16.00%

q (allele a)

0.4000

= 1 - p

p² (AA)

0.3600

= 0.60²

2pq (Aa)

0.4800

= 2×0.60×0.40

q² (aa)

0.1600

= 0.40²

Verification:

p² + 2pq + q² = 0.3600 + 0.4800 + 0.1600 = 1.0000 (= 1)

Try this

  • Set p = 0.6 (the classic NEET example). Read off q, then compute 2pq yourself. Does it match 0.48?
  • What happens to the aa genotype frequency (q²) as you move p towards 1? Why does it almost vanish?
  • If 16% of a population shows the recessive phenotype, q² = 0.16, so q = 0.4. Try setting p = 0.6 and confirm that q² = 0.16.

Human evolution timeline

Walk through the hominid stages from Dryopithecus to Homo sapiens with time period, brain capacity and key features.

Human evolution

Human evolution timeline: walk through each hominid stage

Select any hominid stage from Dryopithecus/Ramapithecus to Homo sapiens. See the time period, approximate brain capacity, posture, and the key features NEET tests. Use the arrows to walk through the sequence in order.

Dryopithecus / Ramapithecus

→

Australopithecus

→

Homo habilis

→

Homo erectus

→

Neanderthal Man

→

Homo sapiens

Time period

About 15 million years ago

Brain capacity

Not well measured (ape-sized)

Posture

Mainly quadrupedal (on all fours); Ramapithecus more upright

Dryopithecus / Ramapithecus

  • Dryopithecus: more ape-like, arboreal (tree-dwelling), walked mainly on all fours
  • Ramapithecus: more man-like, lived partly on the ground, some upright posture
  • Known from fossil teeth and jaw bones found in Africa and Asia
  • Represent the early divergence of the hominid line from apes

NEET fact

Dryopithecus = more ape-like. Ramapithecus = more man-like. Both found about 15 million years ago.

Next stage →

Try this

  • Which hominid was the first to make stone tools? What does the name mean?
  • Walk from Homo habilis to Homo erectus. Which new capability appeared? Why is this important for human evolution?
  • Compare Neanderthal brain size with Homo sapiens brain size. What does this tell you about intelligence and brain size?

Next chapter interactive widgets

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Reproductive Health

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Human Health and Disease

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