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Evolution - Human Evolution

Grade 12CBSEBiology

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Evolution of man occurred approximately 1515 million years ago (mya) starting with primates like DryopithecusDryopithecus (ape-like) and RamapithecusRamapithecus (man-like).

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AustralopithecinesAustralopithecines lived in East African grasslands about 22 mya, walked upright (bipedalism), and used stone weapons but primarily ate fruit.

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The first hominid (human-like being) was HomoHomo habilishabilis, characterized by a cranial capacity of 650−800650 - 800 cccc. They did not eat meat.

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HomoHomo erectuserectus appeared around 1.51.5 mya with a significantly larger brain capacity of 900900 cccc and likely consumed meat.

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NeanderthalNeanderthal man (HomoHomo neanderthalensisneanderthalensis) existed between 1,00,000−40,0001,00,000 - 40,000 years ago in the Near East and Central Asia, possessing a cranial capacity of 14001400 cccc. They buried their dead and used hides to protect their bodies.

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Modern HomoHomo sapienssapiens arose in Africa during the Ice Age (75,000−10,00075,000 - 10,000 years ago). Pre-historic cave art developed about 18,00018,000 years ago, and agriculture started around 10,00010,000 years ago.

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Key evolutionary trends include: Bipedal locomotion, increase in cranial capacity, reduction in brow ridges, development of the chin, and loss of body hair.

📐Formulae

Cranial Capacity (cc): Homo habilis (650−800)<Homo erectus (900)<Homo neanderthalensis (1400)\text{Cranial Capacity (cc): } Homo\ habilis \ (650-800) < Homo\ erectus \ (900) < Homo\ neanderthalensis \ (1400)

Hardy-Weinberg Equilibrium: p2+2pq+q2=1\text{Hardy-Weinberg Equilibrium: } p^2 + 2pq + q^2 = 1

Allelic Frequency: p+q=1\text{Allelic Frequency: } p + q = 1

💡Examples

Problem 1:

Identify the hominid that lived 1.51.5 mya and had a cranial capacity of 900900 cccc. Mention their dietary habit.

Solution:

HomoHomo erectuserectus.

Explanation:

HomoHomo erectuserectus evolved from HomoHomo habilishabilis about 1.51.5 mya. Unlike HomoHomo habilishabilis who were herbivores, fossils suggest HomoHomo erectuserectus probably ate meat.

Problem 2:

Arrange the following in the correct chronological order of their appearance: AustralopithecusAustralopithecus, RamapithecusRamapithecus, HomoHomo sapienssapiens, HomoHomo habilishabilis.

Solution:

Ramapithecus→Australopithecus→Homo habilis→Homo sapiensRamapithecus \rightarrow Australopithecus \rightarrow Homo\ habilis \rightarrow Homo\ sapiens

Explanation:

Human evolution followed the sequence from Miocene primates (RamapithecusRamapithecus, 1515 mya) to Pliocene hominids (AustralopithecusAustralopithecus, 22 mya), then to the first HomoHomo genus (H.habilisH. habilis, 22 mya), and finally modern humans (H.sapiensH. sapiens, 0.0750.075 mya).

Problem 3:

What was the specific characteristic of NeanderthalNeanderthal man regarding their social behavior and brain size?

Solution:

Cranial capacity: 14001400 cccc; Social behavior: Buried their dead and protected their bodies with hides.

Explanation:

NeanderthalsNeanderthals represent a significant leap in both intelligence (14001400 cccc) and cultural development, showing the first signs of ritualistic behavior (burial).

Human Evolution - Revision Notes & Key Diagrams | CBSE Class 12 Biology