class 12 ncert cbse slide presentation of Biology chapterEVOLUTION.pptx

EVOLUTION BIO CLASS XII

2. Sy wee rana
EVOLUTION

» Evolution is an orderly change
from one form to another.

» Evolutionary Biology is the
study of history of life forms on
earth.

WW bankofbiclogy.com

3. ORIGIN OF Fun

4. ORIGIN OF LIFE

5. The Big Bang theory sta! ed about 20 billion
years ago by a ngu 3] =a

> nein al A on ony earths

> O, and NH, released fr ten mass covered
peo 2 =

dei: : Hi

6. Big Y RE

SS ORIGIN OE LIFE .

7. > The ozone layer wi formed. EA

>A site ooled, the wi water vapour fell as rain to foun oceans:
pain four billion years ago, meat |

THEORIES OF ORIGIN OF LIFE Fo

8. THEORIES OF ORIGIN OF LIFE

2 Theory of Abiogenesis

4] 7 Theory of Biogenesis

E y Theory of Panspermia
- Theory of Creationism

( O Theory of Chemical evolution

THEORIES OF ORIGIN OF LIFE

9. THEORIES OF ORIGIN OF LIFE
"4, THEORY OF SPONTANEOUS GENERATION (ABIOGENESIS)

It states that, life came out of decaying
and rotting matter like straw, mud etc.

THEORIES OF ORIGIN OF LIFE

A TLUCMDV ME CONHAITAANICNIIC COAICDATINAL (ADICON?

10. a ee Se a o 7

and rotting matter like straw, mud etc.

THEORIES OF ORIGIN OF LIFE

Louis Pasteur disproved
Abiogenesis theory. Break stem
He demonstrated that life comes only from pre-existing life.

He showed that life did not come from in a closed pre-sterilized
flask. But in an opened flask, life (microbes) appeared.

11. THEORIES OF ORIGIN OF LIFE

NESIS

F Francisco Redi

It is proposed by Francisco Redi,
Spallanzani and Louis Pasteur.
It states that,

But it does not explain origin of
first life.

12. 3. COSMIC THEORY (THEORY OF ANSE .

It states that, the units of life (spores) were

transferred to different planets including me

13. It states that living and non-living was created
by some supernatural power (God).

14. THEORIES OF ORIGIN OF LIFE

> Proposed by Oparin & Haldane.

> It states that, the first form of life was
originated from non-living inorganic
and organic molecules such as CH,,
NH, H,O, sugars, proteins, nucleic
acids etc.

J.B.S Haldane AT Opärin

> ie.

THEORIES OF ORIGIN OF LIFE

15. THEORIES OF ORIGIN OF LIFE
5. THEORY OF CHEMICAL EVOLUTION

UREY-MILLER EXPERIMENT

» Harold Urey and Stanley Miller
experimentally proved theory of
chemical evolution.

» They created a condition like
that of primitive earth (i.e. high
temperature, volcanic storms,
reducing atmosphere with CH,,

te
> NH,, H,0, H, etc.).
WWW. bankofbiology.com

THEORIES OF ORIGIN OF LIFE
5. THEORY OF CHEMICAL EVOLUTION

16. THEORIES OF ORIGIN OF LIFE
5. THEORY OF CHEMICAL EVOLUTION

UREY-MILLER EXPERIMENT

» They made electric discharge in a
closed flask containing CH,, NH;,
H, and water vapour at 800° C.

» Asa result, some amino acids are
formed.

» In similar experiments, others
observed formation of sugars,

tigi vu nitrogen bases, pigment and fats.

THEORIES OF ORIGIN OF LIFE

17. THEORIES OF ORIGIN OF LIFE

> The first non
> They were se

of life originated 3 billion years ago
olic capsule containing macromolecules like

19. ne Se un nn.

Paleontological evidences
Morphological and Anatomical evid en
Biogeographical evidences (Adaptive
Biochemical evidences

Embryological evidences
Evidences for evolution by natural se

WWW bankofbiology.com

vvvvvv

20. VOLUTION

are remnants of life forms found in
rocks (earth crust).

pl » is the study of fossils.

21. v To study
E.g. Horse evolution.

j one °P woolly mammoth
WWW. bankofbiology.com E

22. v To study phylogeny (evolutionary history
or race history). E.g. Horse evolution.

Y To study the connecting link between two
groups of organisms. E.g. Archaeopteryx.

Archaeopt
Connecting link between reptiles and birds

EVIDEN GESHEORZEVOEUTHON

23. EVIDENCES FOR EVOLUTION

To study phylogeny (evolutionary history

or race history). E.g. Horse evolution.

v To study the connecting link between two
groups of organisms. E.g. Archaeopteryx.

v To study about extinct animals. E.g.

Dinosaurs.

EVIDENCES FOR EVOLUTION Wee

24. EVIDENCES FOR EVOLUTION

¿A

Y” To study phylogeny (evolutionary history
or race history). E.g. Horse evolution.

v To study the connecting link between two
groups of organisms. E.g. Archaeopteryx.

v To study about extinct animals. E.g.
Dinosaurs.

v To study about geological period by
analysing fossils in sedimentary rock
layers. The study showed that life forms
varied over time and certain life forms are
restricted to.certain geological time spans.

25. varied over time and certain life forms are
réstricted-to certain geological time spans.

+ Comparative anatomy and morphology shows that different forms of animals
have some common structural features.

* This can be explained as follows:

Homologous organs &
Homology

Analogous organs &
Analogy

26. o Homologous organs: The organs having fundamental
but
This phenomenon is called

| LI

Homologous organs
and Homology

€

27. apa ass ae These forelimbs have different

En gmology functions but similar anatomical structures such as
bones (e.g. humerus, radius, ulna, carpals,
metacarpals & phalanges).

o Homology is also seen in

Hearts of
vertebrates

Brain af

28. Homologous organs Thorns and tendrils of
and Homology Bougainvillea and Cucurbita.

Bougainville

29. EVOLUTION

» Origin of homologous organs is due to Divergent evolution.

> Divergent evolution is the evolution by which related
species become less similar to survive and adapt in
different environmental condition.

Homologous organs
and Homology

bankofbiology.com

— 5
L à AR ae pa

Er:

SVOLUTION

30. The organs having similar function
but different structure and origin. This phenomenon

Analogous organs

and Analogy is called

31. > A bi A. Pl

Analogous organs
and Analogy * Wings of insects (formed of a thin flap of chitin) and
wings of birds (modified forelimbs).

w

32. Analogous organs
and Analogy * Eyes of Octopus (retina from skin) and mammals
(retina from embryonic brain).

33. FOR EVOLUTION

¡TOMICAL EVIDENCES

Analogous organs Examples
and Analogy * Flipper of Penguins and Dolphins.

EVIDENCES FOR EVOLUTION Pay

34. Analogous organs
and Analogy

35. Analogous organs
and Analogy * Trachea of insects (from ectoderm) and lungs of

vertebrates (from endoderm).

36. EVIDENCES.FOR EVOLUTION.

37. =. RORIEVOLUTION y

EVIDENCES

> Organisms show similarities in proteins, genes, other biomolecules &
metabolism.

» It indicates common ancestry.

Toe
i

Transcription

Replication

38. ptive radiation (evolution by adaptation)
the evolution of different species ina

geographical area starting from a point.

* Eg.
Y Darwin's finches in Galapagos islands.

39. (evolution by adaptation)
the evolution of different species in a

geographical area starting from a point.
* Eg.
Y” Darwin's finches in Galapagos islands.

Y Australian marsupials (Marsupial
radiation).

EVIDENCES FOR EVOLUTION

40. Adapti (evolution by adaptation)
is the evolution of different species in a
geographical area starting from a point.

° Eg.

Y” Darwin's finches in Galapagos islands.

Y Australian marsupials (Marsupial
radiation).

Y” Placental mammals in Australia.

7 Lemur

EVIDENCES FOR EVOLUTION

41. EVOLUTION

BIOGEOGRAPHICAL EVIDE!

> When more than one adaptive radiation is appeared in an
isolated geographical area, it results in convergent evolution.
E.g. Australian Marsupials and Placental mammals.

Mole Marsupial mole

Ant eater Numbat (Ant eater)
Mouse Marsupial mouse
Lemur Spotted cuscus
Flying squirrel Flying phalanger
Bobcat Tasmanian tiger cat

Wolf Tasmanian wolf

42. > Proposed by Ernst Haeckel. bar

» He observed that all
are absent in adult.

> E.g. all vertebrate embryos (including human) develop
just behind the head. But it is functional only in fish and not found in
other adult vertebrates.

Reptile Bird

43. '

Vestigial gill slit

» However, Karl Ernst von Baer rejected this proposal.

» He noted that embryos never pass through the adult stages of
other animals.

Reptile

44. Fish Reptile Bird Human Vestigial gil suit Ñ

is the process by which the organisms that are best suited for
their environment survive and reproduce.
* Some examples are given below:

Industrial melanism These are the
examples for

Development of

in organisms against (evolution due to
herbicides, pesticides, human activities).
antibiotics or drugs etc.

EVIDENCES FOR EVOLUTION Nindows

45. There were more white
winged moths (Biston betularia) on trees than dark winged or
melanised moths (Biston carbonaria).

More dark winged moths and less
white winged moths.
Industrial : > à
melanism Te |

EN

B. betularia

B. carbonaria

ENCES FOR EVOLUTION

46. SVOLUTION

REASON
Before industrialization: bankofbiology.com
There was thick growth of white coloured covered the trees.
In that background, the white winged moths survived but the dark
coloured moths were picked out by predators.
Industrial 4
melanism

EVIDENCES FOR EVOLUTION

47. EVIDENCES FOR EVOLUTION

; ON BY NATURAL SELEC
REASON
After industrialization:

Tree trunks became dark due to industrial smoke & soots. No lichens.
Under this condition, white winged moth did not survive because the

predators identified them easily.

Dark winged moth survived because of suitable dark background, i.e.

Industrial predators could not identify them.

melanism

48. OF BIOLOGICAL
EVOLUTION

49. CVULUTIUN

Theory of Lamarck (Lamarckism
or Theory of Inheritance of
Acquired characters)

Darwinian Theory (Darwinism or

Theory of Natural selection)

Mutation Theory of de Vries

50. bankofbiology.com

It is proposed by

It states that evolution of life forms
occurred by the

51. o Acquired characters are developed by use and disuse of organs.

E.g. Long neck of giraffe is due to continuous
elongation to forage leaves on trees. This acquired character was inherited to
succeeding generations.

E.g. Disappearance of limbs in snakes.

52. This theory was eliminated out because it is
proved that the characters are inherited only
through genes.

53. DARWINISM (THEORY OF NATURAL SELECTION)

Proposed by Charles Darwin.

It was based on observations during a sea voyage in a sail ship called H.M.S. Beagle.
Alfred Wallace (a naturalist worked in Malay Archepelago) had also come to similar
conclusions.

Work of Thomas Malthus on populations influenced Darwin.

54. i + 4, |
Alfred Wallace Thor Malthus

Darwinism is based on 2 key concepts:

bankofbiology.com
1. Branching descent:

Branching descent
It explains that all organisms are modified
descendants of previous life forms.

Common ancestor

55. Darwinism is based on 2 key concepts:

Resistant bacteria
1. Branching descent:

It explains that all organisms are modified
descendants of previous life forms.
2. Natural selection:
Consider a bacteria! Resistant bacteria
given medium. If the medium composition outgrows
is changed, only a part of the population
can survive under new condition. This
iant popu n (B) outgrows the others - -
and apps as new species, i.e. B is bette:
. Thus, nature

= Colony B
cl for fitness; mi

56. L EVOLUTION

__ DARWINISM Es OF URL SELECTION)

Natural selection is based on the
following facts:

Heritable minor variations
Overproduction

Limited natural resources

Struggle for existence

Survival of the fittest

57. eel
Survival of the fittest

It is either beneficial or harmful to the organisms.

Population size grows exponentially due to maximum reproduction (E.g. bacterial
population).

Resources are not increased in accordance with the population size.

LE
ye
‘à

58. THEORIES OF BIOLOGICAL

DARWINISM (THEORY OF NATURAL

It is the competition among organisms for resources so that population size is limited.

In struggle for existence, organisms with beneficial variations can utilize resources better.
Hence, they survive and reproduce. This is called Survival of the fittest. It leads to a
change in population characteristics and new forms appear.

| Darwin ignored about origin of variation and mechanism of evolution or speciation.

e =

VWHEORIES OF BIOLOGICAL EVOLUTION
MECHANISM OF EVOLUTION

59. » Hugo de Vries proposed Mutation Theory of evolution.

» He conducted some experiments on evening primrose
(Oenothera lamarckiana) and believed that evolution
takes place through mutation and not by minor

variation.

60. > Darwinian variation is or, slow & C It results in
> Mutational variation is s and s. Here, speciation is by
(single step, large mutation).
Mutation is the origin of variation for evolution.

TY) E AR

5 www

ALL,
:$8 ww
$ w

61. HARDY- WEINBERG PRINCIPE

62. o It says that

o The (total genes and their alleles in a population) remains a constant.
This is called

A population of 20 beetles.
Each beetle is a gene pool.

Their totality is the gene
pool of that population.

o E.g. Consider, in a diploid, p & q EPP

63. o E.g. Consider, in a diploid, p & q
are the frequencies of alleles A
and a respectively.

= P e Here, total number of alleles A & a = 40 (A = 26 & a = 14)
[binomial expansion of (p+a)?] EPP 6/40 = 0.65 | Total allelic frequency
Frequency ofa=q=14/40=0.35 | (P*9)=1
Change of frequency of alleles in No. of beetles = 20 (Genotypes: AA = 10, Aa

a population disturbs Hardy-

Weinberg equilibrium.

This change is due to evolution.

Frequency of genotype AA = 10/20 = 0.5
Frequency of genotype Aa = 6/20 = 0.3
Frequency of genotype aa =4/20 = 0.2

64. MIS CI EVOIUUO
JB 21 COLE?) Frequency of genotype aa = 4/20; 0.2

SIPLE

Genetic drift

65. low from one population to another.
% Here gene frequencies change in both populations.
% Gene flow occurs if migration happens multiple times.

66. PRINCIPLE

FACTORS AFFECTING HARDY-WEINBERG EQUILIBRIUM

* Gene flow by chance causing change in frequency.

< Sometimes, change in frequency is so different in the new
sample of population that they become a different species.

% The original drifted lation becomes founders and the
effect is called foun: ) fbio

FACTORS AFFECTING HARDY-WEINBERG EQUILIBRIUM

67. island

IG HARDY-WEINBERG

It results in formation of new phenotypes.
Over few generations, this leads to speciation.

Incoming
UV photon

68. HARDY: WEINBERG PRINCIPLE
CTING HARDY-WEINBERG EQUILIBRIUM

It is the reshuffling of gene combin ns during
crossing over resulting in genetic variation.
Homologous Chromosome Recombinant

chromosomes crossover chromosomes
aligned

69. 3 types of natural selection |

||
Stabilizing Directional Disruptive
selection selection selection

70. FACTORS AFFECTING HARDY-WEINBERG EQUILIBRIUM

1. Stabilizing selection

» Here, more individuals acquire mean character value
and variation is reduced. bankofbiology.com

Peak gets higl ner
and narrower

CACP?TADC ACCORTIAIC LIADNV \ADIMDEDrT Ei IODDILINA

71. * Here, Individuals of one extreme (value other than
mean character value) are more favoured.

ts in

one direction 4

FACTORS AFFECTING HARDY-WEINBERG EQUILIBRIUM

72. FACTORS AFFECTING HARDY-WEINBERG EQUILIBRIUM

uptive selec:

* Here, Individuals of both extremes (peripheral
character value at both ends of the distribution curve)
are more favoured.

73. E.g. Fur colour
of rat

One direction Poriginal Evolved —_ Phenotypes (tur color)
A population population I

Ng

A. Stabilizing selection

À Dusoueial soltado NP... UN
Ci Directicnal aslectica ablzgaeteguon | Dretioaiseifehenf Digtupve selection

74. > 2 e ©
ES PS RUE NE
AA

ABRIEF ACCOUNT OF EVOLUTION

75. A BRIEF ACCOUNT OF EVULUTIUN

The geological time scale
includes 4 eras:

+ Proterozoic

+ Palaeozoic

+ Mesozoic
+ Cenozoic

PROTEROZOTE.

76. » First cellular forms of life appeared (2000
mya).

» Some of the cells had the ability to
release O, as the light reaction in
photosynthesis.

» Single celled organisms became
Multicellular organisms.

77. It has 6 periods:

»
>
>

Cambrian (540 - 490 mya)
Ordovician (490 - 443 mya)
Silurian (425 mya)
Devonian (405 mya)
Carboniferous (360 mya)
Permian (285 mya)

78. WWW bankofbiclogy.c

> 500 mya: Invertebrates were formed.

> 450 mya: First land organisms (plants)
appeared.

EVOLUTION

79. 2016 ERA (540 =

» 500 mya: Invertebrates were formed.

» 450 mya: First land organisms (plants)
appeared.

» 400 mya: Arthropods invaded the land.

» 350 mya: Jawless fishes were evolved.

WWW bankofbiology.com

80. » 500 mya: Invertebrates were formed.

> 450 mya: First land organisms (plants)
appeared.

» 400 mya: Arthropods invaded the land. Lobe-nned tien

» 350 mya: Jawless fishes were evolved.
(stout & strong finned fishes) could
move on land and go back to water. They
evolved to first amphibians (ancestors of
modern day frogs & salamanders).

WWW. bankofbiology.com

81. » 500 mya: Invertebrates were formed.

» 450 mya: First land organisms (plants)
appeared.

» 400 mya: Arthropods invaded the land.

» 350 mya: Jawless fishes were evolved.
(stout & strong finned fishes) could
move on land and go back to water. They
evolved to first amphibians (ancestors of
modern day frogs & salamanders).

WWW. bankofbiology.com

82. » 500 mya: Invertebrates were formed.

» 450 mya: First land organisms (plants)
appeared.

» 400 mya: Arthropods invaded the land.
» 350 mya: Jawless fishes were evolved.

Lobefins (stout & strong finned fishes) could
move on land and go back to water. They
evolved to first amphibians (ancestors of
modern day frogs & salamanders). coelacanth is still very much alive.

In 1938, a lobe-fin called coelacanth fish was caught in South Africa which was
Ñ thought to be extinct.

EVOLU)

83. in} I A ad

» 500 mya: Invertebrates were formed.

» 450 mya: First land organisms (plants)
appeared.

» 400 mya: Arthropods invaded the land.

» 350 mya: Jawless fishes were evolved.
Lobefins (stout & strong finned fishes) could
move on land and go back to water. They
evolved to first amphibians (ancestors of
modern day frogs & salamanders).

In 1938, a lobe-fin called coelacanth fish was caught in South Africa which was

| thought to be extinct.
a

84. » 500 mya: Invertebrates were formed.

» 450 mya: First land organisms (plants)
appeared.

» 400 mya: Arthropods invaded the land.

» 350 mya: Jawless fishes were evolved.

Lobefins (stout & strong finned fishes) could
move on land and go back to water. They
evolved to first amphibians (ancestors of
modern day frogs & salamanders).

In 1938, a lobe-fin called coelacanth fish was caught in South Africa which was
thought to be extinct.

85. was caught in South Africa which was
thought to be extinct.

» 320 mya: Sea weeds and few plants
were existed.

> Amphibians evolved to reptiles.
They lay thick-shelled eggs (do not
dry up in sun).

» Giant ferns (Pteridophytes) were
present but they all fell to form coal

deposits slow!
WWW. bankofbiclogy.com

86. > Age of reptiles & gymnosperms.
> It has 3 periods:

+ Triassic (230 mya)

+ Jurassic (208 mya)

+ Cretaceous (144 mya)

87. > 200 mya: Some of the land reptiles went
back into water to evolve into fish-like
reptiles (E.g. Ichthyosaurs).

88. » 200 mya: Some of the land reptiles went
back into water to evolve into fish-like
reptiles (E.g. Ichthyosaurs).

» The land reptiles were dinosaurs.
(Tyrannosaurus rex, Triceratops,
Stegosaurus, Brachiosaurus etc.).

5 {
WWW bankofbiology.com ae

Windows

89. WWW. bankofbictogy.com

» 200 mya: Some of the land reptiles went
back into water to evolve into fish-like
reptiles (E.g. Ichthyosaurs).

» The land reptiles were dinosaurs.
(Tyrannosaurus rex, Triceratops,
Stegosaurus, Brachiosaurus etc.).

WWW. bankofbiology.com

90. > 200 mya: Some of the land reptiles went
back into water to evolve into fish-like
reptiles (E.g. Ichthyosaurs).

» The land reptiles were dinosaurs.
(Tyrannosaurus rex, Triceratops,
Stegosaurus, Brachiosaurus etc.).

WWW. bankofbi

91. : BRACHIOSAURUS
> 200 mya: Some of the land reptiles went

back into water to evolve into fish-like
reptiles (E.g. Ichthyosaurs).

> The land reptiles were dinosaurs.
(Tyrannosaurus rex, Triceratops,
Stegosaurus, Brachiosaurus etc.).

y
WW bankofbiology.com

92. WWW. bankofbiology.com ss

» 200 mya: Some of the land reptiles went
back into water to evolve into fish-like
reptiles (E.g. Ichthyosaurs).

Là en. PA

The land reptiles were dinosaurs. ae \ + ‘a NA
A A = U

(Tyrannosaurus rex, Triceratops, Dati En) Vu yan À

Stegosaurus, Brachiosaurus etc.).

> T. rex was the largest dinosaur (20 feet in
height, huge fearsome dagger-like teeth).

i ed birds were emerged.
WWW. bankofbiology.com
EVOLUTION

93. > Age of Mammals & Angiosperms.
» It has 2 periods:

WWW. bankofbiology.com

94. COEN

» 65 mya: Dinosaurs suddenly
disappeared. Some say climatic
changes killed them. Some say most
of them evolved into birds.

EVOLUTION

95. 65 mya: Dinosaurs suddenly
disappeared. Some say climatic
changes killed them. Some say most
of them evolved into birds.

First mammals were shrew-like. Their -

fossils are small sized.

96. »

In South America, there were mammals
resembling horse, hippopotamus, bear,
rabbit etc.

Due to continental drift, when South
America joined North America, these
animals were overridden by North
American fauna.

97. » In South America, there were mammals
resembling horse, hippopotamus, bear,
rabbit etc.

Due to continental drift, when South
America joined North America, these
animals were overridden by North
American fauna.

Due to continental drift, Australian
Marsupials survived because of lack of
competition from any other mammals.

98. =
2 ret

ER Y oes 15

LH
bi es

ON RENNM AN) VON RE PION) oye MVAN

99. | EVOLUTION

IN AND EU IN

100. » 15 mya.

> Hairy.

> Walked like gorillas and chimpanzee.
> More ape-like.

> More man-like.

m Dryopithecus Ramapithecus

101. WWW. bankofbiology.com

> 3-4 mya, there were man-like
primates in eastern Africa.

> They had height up to 4 feet and
walked up right.

» This belief is based on fossils of
man-like bones found in Ethiopia
& Tanzania.

WWW. bankofbiology.com

102. > Lived in East African grass lands.
> Hunted with stone weapons.
> Ate fruits.

103. HOMO nASIUIS

» 2mya.
> First human-like being (hominid).
> Brain capacity: 650-800 cc.

» Did not eat meat.

104. » 1.5 mya.
» Brain capacity: 900 cc.
> Ate meat.

105. =

> 1 lakh - 40,000 years ago.
» Brain capacity: 1400 cc.
> Lived in East and Central Asia.

» Used hides to protect their body.

ied their dead.
WWW. bankofbiology.com

EVOLUTION

106. > Pre-historic cave art developed about

» Agriculture and human settlements:

EVOLUTION

107. SEQUENCE OF HUMAN
EVOLUTION

Ramapithecus
Australopithecus
Homo habilis

Homo erectus

WH

Homo sapiens

LUTION

108. [ EVOLUTION

HOMINID FAMILY
oz 7 a A Y Ed
& &

m a:
©
Ap
ER,

WWW. bankofbiology.

109. Acomparison of the skulls of
a. Adult modern human being
b. Baby chimpanzee
c. Adult chimpanzee

The skull of baby chimpanzee is more like adult
human skull than adult chimpanzee skull.