1. Would You Believe Me If I Told
You That the US Spends crores of
Dollars on a Project Called SETI
(SEARCH FOR EXTRA
TERRESTRIAL INTELLIGENCE)
Which Searches the Outer Space
for Signs of Life !!!
Do You Believe in Aliens?

2. YES,THERE MAY BE ALIENS!
 The story that I am about to tell you is the
story of how life began.
 Scientists think it is likely that somewhere out
in the universe amongst the millions of solar
systems there may be another planet where
this story is just unfolding.
 The story of :
HOW LIFE BEGAN ON EARTH

3. BUT WHAT IS LIFE?
WHATEVER
Reproduces
Gets and Uses Energy
Has cellular structure
Responds to stimuli
Excretes waste matter
HAS LIFE

4. SO HOW DID LIFE BEGIN
ON EARTH ?
 4.6 billion years ago the
earth was just
beginning to calm down
after a violent birth. The
atmosphere still had no
oxygen and noxious
fumes of ammonia,
carbon dioxide, sulphur
dioxide enveloped
earth.

5. Oceans were the cradle of life
 The sea was a soup of different
chemicals that came down with the
rain. Lightening fueled some very
interesting reactions and compounds
now only found in living things were
formed inorganically in the sea water.
 These chemicals formed
stable colloidal complexes
called COACERVATES

6. The First Cell Is Born!
 These inorganically formed coacervates
had to work out a method of
reproduction. They needed a genetic
material.
 The also needed a cell membrane.
 Nobody is certain how but they got it.
 The first cell fossils are called
stromatolites and they are 3.5 billion
years old.

7. Things now begin to get more
complex
The new cell has a virgin environment
before it.
How will it tap all the resources available
to it?
How will it become more efficient?
How will it become a better survivor?
How will it leave behind its genes?

8. How do we know about this
story?
 From Fossils found in rocks
 By studying anatomy of closely related
animals
 By studying animals that have
intermediate characteristics between
different groups.The missing links
 By studying the embryological
developmental stages.

9. Lets look at a fossil of an animal that is
not found today.
 This is the
fossil of the
Archeopteryx.
 It is a missing
link between
birds and
reptiles

11. Protista (Unicellular Eukaryotes)
Photosynthetic
Protista
Decomposer
Protista
Protozoan
Protista
1. Euglenoid
2. Dinoflagellate
3. Diatoms
4. Slime moulds
5. Sarcodina
6. Ciliata
7. Mastigophora
8. Sporozoa

12. Common Features of Protista
1. Eukaryotic cells
2. Photosynthetic or heterotrophic
3. Unicellular e.g. Amoeba, Paramoecium etc.
4. Prototists are thought to have been the
ancestors of animals, plants and fungi, i.e. they
were the unicellular eukaryotic cells..

13. Amoeba proteus is busy capturing a ciliate by surrounding it
with its pseudopodia. The nucleus can be seen just below the
pseudopodia. Bottom left is a water expelling vesicle. Amoebas
locomote almost like a fluid. Although amoebas are 'shape-
shifters' their shapes limit to a certain range. Each species has its
own 'repertoir'
Pseudopodia
Food (bacteria)
Nucleus
Contractile vacuole
(excrete water etc.)
Protozoa: Sarcodina (all have pseudopodia)
Amoeba

14. Ceratium hirundinella,a dinoflagellate. one
of the flagella is just visible. The other runs
through the girdle (dark stripes in center
image)
2nd Flagella
1st Flagella
Photosynthetic Protista: Dinoflagellata (2 flagella perpendicular to one another):

15. Noctiluca (Photosynthetic Protista)

16. Single celled ‘animals’ -
Protozoans
Contractile vacuole
Gullet
Ciliia
Nucleus
Paramoecium

17. Paramecium bursaria, a green slipper
animalcule. It gets its colour by symbiotic algae,
Chlorella. They are visible as small round cells.
Paramoecium (Ciliata)
Cilia all ovedr the body

18. Bell animalcules are common in
fresh water but can also be found in
the sea. These colonial Ciliates live
attached to a stalk. Find out more
about their fresh water relatives on
the smallest page on the web
Colonial ciliates
Cilia
Individual Zooids)
Stock

19. Diatom, Photosynthetic Protista
Diatom

20. Desmids like this Micrasterias rotata are
amongst the most beautiful microscopic
organisms. They are conjugating green algae.
Unicellular Plants: Algae

21. Some are Multicellular
Algae: Volvox Colony

22. Single celled ‘plants’- algae
Desmid

24. (Body with pores)
Flat Worms & Round
(Jointed Legs)
(Spine on skin)
Notochord,
Dorsal tubular nerve cord,
Gill slits

25. Phylum Porifera (Sponges)
1. No distinct tissue layer (although 2 layer of cells)
2. Presence of numerous pores throughout the body
3. Presence of Choanocytes ( collar cells)
4. Spicules mostly made up of calcareous, silicious or spongin fibre
5. Mostly marine

26. Porifera: A body full of holes.
 Body covered with tiny pores
 No tissue organisation
 Sessile, filter feeder
 Spicules present
 Choanocyte cell and extensive canal
system present.

27. Sponge (Porifera)
Porifera
Osculum)
Spicules
Ostia

31. Phylum Cnidaria
1. Body with distinct tissue system: 2 layers:
Ectoderm & Endoderm
2. Presence of nematocyst cells
3. One gastrovascular cavity (Coelenteron)
4. Can be polyp, medusoid or both form
Polyp
Medusa
Coelenteron
Tentacle(with nematocyst)

32. Cnidaria (Coelenterata)
 Presence of nematocyst
 Bag like body with one opening guarded by
finger-like tentacles.
 Radial Symmetry
 Two layer of cells (diploblastic).Network of
nerve cells present.
Polyp form Medusa form
Ectoderm
Endoderm
Tentacles

38. The Hydra is a fresh-water polyp that can extend its
flexible body to an extreme and reach a length of 2 centimeters.
The tentacles bear tiny harpoon-like organs called nematocysts.
These are used for capturing waterfleas and other small
crustaceans. It can turn itself inside out and has amazing
capabilities of regeneration!…
Tentacle with
Nematocyst
Mouth
Foot
Phylum: Cnidaria ( 2 layer of
Tissue: Ectoderm & Endoderm)

39. Obelia Medusa ( Cnidaria )
Obelia medusa
Tentacles with nematocyst
Manubrium (Mouth)
Gonads

40. Jelly fish

41. Ctenophora

42. Ctenophora

43. Platyhelminthes
 Bilateral Symmetry
 Three tissue layers
 Dorsoventrally flattened
 Acoelomate solid body
 Well developed tissues like nerves etc
but no blood vascular system.
 Incomplete digestive system or absent

44. Flatworms are multicellular organisms. They
posses simple eyes and a simple nervous system.
The mouth can be found underneath in the center.
The flatworm body is covered with tiny cilia used
for locomotion.
1. Body dorsoventrally flattened
2. Solid with distict 3 tissue layer
3. Acoelomate

45. The Flatworm (Planaria)
Eye spot
Ciliated body surface

46. Tape worm as parasite inside the Dog
bakerinstitute.vet.cornell.edu

47. Tape worm
Taenia solium
www.medicalook.com

48. Liver Fluke
www.student.loretto.org

49. With courtesy from:-
Website:sph.bu.edu
Platyhelminthes

50. Aschelminthes: Round Worms
 Mouth and Anus present
 Body round in cross-section
 Pseudocoelomate body
 Sexes separate
Round worm (Pseudo coelomate body, round in cross section
& distinct mouth and anus)

51. Ascaris lumbricoides

52. Hookworm– Anchylostoma
With courtesy from:-
Website:sph.bu.edu

53. Annelida: The segmented
worm
 Body metamerically segmented
 Blood vascular system present
 Setae present for locomotion
 Nerve ring present
 Nephridia for excretion
 Hermaphrodite has both male and
female reproductive organ

54. Earthworm
Pheretima posthuma

55. Photocredit:- www.flickr.com -
Polychaeta worm: Nereis

56. Leech
Hirudinaria granulosa
Anterior
sucker
Posterior
sucker

57. Arthropoda (Chitinous exoskeleton & jointed legs)
Arthros = Jointed
Podos = Legs

58. Arthropoda: Largest group of
living organism
 Presence of hard exoskeleton
 Presence of jointed legs
 Open circulation
_________________________________

59. Velvet worm (Peripatus)
Photocredit::www.fs.usda.gov

60. Peripetus
www.teara.govt.nz

61. Myriapoda
 Centipede Scutegera
www.swellvoyage.com
superscientastic.blogspot.com

62. Fly with compound Eye

63. Hermit Crab

64. www.montereybayaquarium.org
Barnacle (closed)
Barnacle (Open)

65. Crab (Crustacea)

66. Spider (Arachnida)

67. Wolf Spider (Arachnida)

68. Spider (Arachnida)

69. www.enchantedlearning.com www.medtogo.com
Scorpion

70. Mollusca (Muscular foot and mantle usually
which secrete shell
Periwinkle, Gastropoda very common in sea-shore, eat dead animals.

71. Mollusca: They have soft body
 Soft unsegmented body
 Presence of mantle covering the body
which usual secretes shell

72. Cone Shell

73. Slug

74. Gastropod snail

75. Bivalve

76. Mytilus
(with mysis- the thread for attachment)

77. One valve (shell) of Bivalvia

78. Top - Shell

79. OCTOPUS

80. SQUID

81. NAUTILUS

82. www.fantasticforwards.com
Nautilus Shell (showing gas-chamber)

83. Echinodermata: Spiny skin
 Calcareous spines on the skin
 Water vascular system with tube feet.
 Larva bilateral but adult radial symmetry

84. Echinodermata
Characters:
1. Presence of echinus, calcareous spicules
2. Body divided into oral and aboral side
3. Presence of water vascular system & tube feet
4. Exclusively marine
5. Larval stage motile with bilateral symmetry but
in adult radial symmetry

88. wiki.hicksvilleschools.org
Brittle Star

89. Feather- star

91. Balanoglossus : Hemichordate
• Stomochord instead of Notochord
• Gill slits
• Nerve-cord not dorsal

92. Chordata
 Notochord present
 Dorsal,tubular nerve cord
 Pharyngeal gill slits
 Post anal tail
 Closed Vascular system

93. A generalized chordate showing fundamental
chordate characters
engage.intel.com/.../phylum%20chordata%20and%20protochordates.ppt

94. Ideal Chordate Structure
Notochord
Nerve cord
Gill Slits
Post-anal tail

95. Sub Phylum: Urochordata
 Bag-like,sessile,marine organism
 Adult body covered by tunic
 Notochord present in larva only in tail
 Nerve cord present in larva but
degenerates in adult
 Pharyngeal gill slits
 Ex: Doliolum sp. Salpa sp. (Ascidians)

96. forum-psicologos.blogspot.com -

97. Ascidia (Urochordata) Larva
commons.wikimedia.org

98. Sub Phylum: Cephalochordata
 Notochord present throughout the life
 Dorsal,tubular nerve cord extended up
to head
 Pharyngeal gill slits distinct

99. Amphioxus ( Cephalochordates)

100. Sub Phylum: Vertebrata
 Presence of skull (Craniata)
 Notochord modified into bony vertebra
in adult
Vertebra
Nerve chordsSkull (Cranium) covering brain

101. Super Class: Agnatha
Class: Cyclostomata
 No jaws
 Pharyngeal gill slits with pouches
 Mouth circular
 Body cartilagenous
 All marine
 Unpaired fins (no paired appendages)
Example: Lamprey(Petromyzon sp.) Hagfish
(Myxine sp.)

103. PETROMYZON
CYCLOSTOMATA

104. Sub Phylum : Gnathostomata
 Presence of jaws
 Presence of paired appendages
Upper jaw
Lower jaw
Paired Appendages

105. Class: Chondrichthyes
(Cartilagenous fish)
 Endoskeleton made up of cartilage
 Gills without operculum
 Paired and unpaired fins without fin-rays
 Mouth ventral
 Tail or caudal fin heterocercal
 Heart 2 chambered
Example: Sting-ray(Trygon sp.) Shark, Electric
–ray (Torpedo sp.)

108. Class: Osteichthyes
 Bony endoskeleton
 Gill-slits covered by operculum
 Fins with fin-rays
 Tail fin homocircal
 Presence of swim-bladder
 Heart 2 chambered
Ex: Gold fish, Eel, Sea-horse, Flying fish

109. Osteichthyes (Bony fish)

110. Eel

111. Glass fish

115. Class: Amphibia
 Tadpole larva grows in water and adult is
terrestrial (i.e. two stages in the life cycle-
aquatic and terrestrial)
 Moist skin
 Two pairs of pentadactyl limbs
 3 chambered heart
 Respire through gills(in larva), lungs and
moist skin (in adult)
Ex: Caecilian(Icthyophis sp.), Salamander
(Salamandra sp.), Toad (Bufo melanostictus),
Frog (Rana tigrina)

118. Class: Reptilia
 Terrestrial organisms with pentadactyle
clawed digits and four limbs (Tetrapods)
 Respiration only by lungs
 Body covered with dry scales
 Heart 3 ½ chambered ( except
crocodiles were it is 4 chambered)
Ex: Tortoise, Crocodile, Lizard, Snake,
Chameleon

121. Reptilia

126. Class: Aves (Birds)
 Presence of feather
 Beak without teeth
 Forelimbs modified into wings
 Hollow bones
 Homeotherm (Warm blooded)
 4-chambered heart
Ex: Peacock (Pavo cristatus), Ostrich (Struthio
sp.) Albatross, Purple sun-bird

131. Class: Mammalia
 Presence of mammary gland
 Hairs all over the body
 Give birth to young ones (except Platypus
and Echidna)
 External ear (Pinna) present
 Placenta present in most
 Diaphragm present
 4 chamberd heart
Ex: Whale, Seal, Elephant, Bat, Man,Kangaroo, Platypus

132. The African Elephant

133. Class Mammalia

134. Sub-Class: Prototheria
(Egg-laying mammal)
 Lays reptile-like egg
 No external ear
 No placenta
 Body not properly homeotherm
 Mammary gland without niples
Example: Platypus(Ornithorhynchus sp.)
Echidna ( Tachyglossus sp.)

136. Sub Class: Marsupiala
 Placenta yolk-sac type
 Presence of marsupium (Pouch)
 Immature babies born inside marsupium
 Ex Kangaroo(Macropus),Wombat,
Koala, Opossum

138. Sub Class Eutheria
(Placantal mammal)
 Presence of true placenta(allanto-
chorionic)
 Urino-genital apparatus and anus
separate

139. Placental mammal
 Order Insectovora-shrew
 Order Rodentia-rat,squirrel
 Order Primate.Ex Monkey,Gorrila,Man
 Order Chiroptera-bat(Pteropus sp.)
 Order Cetacea-dolphin,whale.
 Order Carnivora-tiger,dog,cat
 Order Artiodactyla-deer,giraffe,cow

142. The Polar Bear

156. Compiled by:-
Jyoti Parruck
jparruck@gmail.com
9312690129
(taken help from CD and NET)