Objective of this presentation is to introduce first year Biological Sciences Students in Nigerian Universities on various forms of life in the Animal Kingdom.

1. DEPARTMENT OF BIOLOGICAL SCIENCES,
ADMIRALTY UNIVERSITY OF NIGERIA, DELTA-NIGERIA.
BIO 102: ANIMAL DIVERSITY
INTRODUCTION TO DIVERSITY OF LIFE
BY
MUSA, SAHEED IBRAHIM
B.Sc. Hons (Saudi), M.Sc. (Unilag), Ph.D. (Uniben).

2. ANIMAL DIVERSITY
29 days to go…..

3. ANIMAL DIVERSITY
 Any of a group of multicellular eukaryotic organisms
 They are thought to have evolved independently from the unicellular
eukaryotes
 They have animal cells
 Have developed muscles and
hence mobility, a characteristic that
has stimulated the further development of
tissues and organ systems
 Multicellularity (Roundworm C. elegans, has 1,031 cells)

4. ANIMAL DIVERSITY
 Eukaryotic cell structure
 Specialized tissues: Stem cells, diversify into four broad categories nervous
tissues, connective tissues, muscle tissues, and epithelial tissues, with
exception of sponges, which are technically animals but have virtually no
differentiated cells.

5. ANIMAL DIVERSITY
 Sexual reproduction: Except certain species of sharks, are capable of
reproducing asexually
 A blastula stage of development
 Motility: except sponges and corals, are virtually immobile once they're fully
grown, but their larvae are capable of movement before they become rooted
to the sea floor

6. ANIMAL DIVERSITY
 Heterotrophy
 Nervous system: Such as mammals that are
sufficiently advanced to possess more-or-less acute
senses of sight, sound, hearing, taste and touch

7. ANIMAL DIVERSITY
 Cells lacks cell wall
 Their bodies are held together by structural proteins called collagen fibers
 1.3 million living species of animals have been identified
 Diploid stage is found dominating the life cycle
 After sperm fertilizes the egg, the zygote undergoes rapid cell division to produce
cleavage
 Cleavage leads to the formation of morula, them blastula
 Blastula undergoes gastrulation to gastrula with different layers of embryonic tissues

8. ANIMAL DIVERSITY
 Some have at least one larva stage: A larva is sexually
immature and morphologically distinct from the adult and
eventually undergoes metamorphosis

9. ANIMAL DIVERSITY
 Evolution of animal starts from:
Neoproterozoic Era : Fossils
Paleozoic Era: Cambrian explosion
Mesozoic Era: Dinosaurs time
Cenozoic Era: Modern mammals, insects and marine
animals
 Zoologist study Animals

10. ANIMAL DIVERSITY
1. Based body size: Different animals have different body
shapes and sizes. This indicate the nature of molecular and
biochemical activities.
 (A) Microscopic animals: These are animals that are only
visible with the help of a microscope. These include
Amoeba, Hydra, Cyclops, Daphnia
 (B) Large animals: These are those that can be seen with
eyes, without the use of a microscope or magnifying lens
such as Mosquito, Leech and Mammals.

11. ANIMAL DIVERSITY
2. Based on body symmetry/body plan: This is the repetition of the parts in an
animal or plant in an orderly fashion. Specifically, symmetry refers to a
correspondence of body parts, in size, shape, and relative position, on opposite
sides of a dividing line or distributed around a central point or axis.
 (A) Asymmetry: This are not capable of being halved in any plane, such as
animals with no pattern or symmetry e.g sponge.
 (B) Bilateral symmetry: This are capable of being halved by only one plain,
it separates the animal into roughly mirror image right and left sides. E.g
Cockroach, Lizard, Frog, Man etc
 (C) Radial symmetry: This has longitudinal (up and down) orientation,
capable of being halved in many planes producing roughly mirror-image
halves. E.g. Sea anemones, Jelly fish, Star fish, etc

12. ANIMAL DIVERSITY
(C) Radially Symmetry
(B) Bilateral Symmetry

13. ANIMAL DIVERSITY
3. Based on habitat: Animals are also classified based on their habitats. Habitats are the
home or dwelling place of an animal. It includes its activities and niche.
(A) Terrestrial animals: These are animals that are found
(B) Aquatic animals: These are found living in water. These can either be:

14. ANIMAL DIVERSITY
3. Based on habitat:
(C) Flying: These are animals that fly most times of their lives. Such as Butterfly, Birds
(D) Tree-living or Arboreal: They are found living on trees such as Tree frog, Phyton,
Monkeys

15. ANIMAL DIVERSITY
3. Based on habitat:
(E) Desert dwellers: These are the animals found living in the desert are such as
Camel, Meerkat, etc
(F) Polar animals: These are the animals found inhabiting the Polar Regions such as
white bear, antelope and penguin.

16. ANIMAL DIVERSITY
3. Based on habitat:
(G) Forest dwellers: These are the animals found in the forest such as bear, deer and
monkies.
(H) Mountain dwellers: They are found living on mountains and valleys. They include
Giraffe, mountain Goat etc

17. ANIMAL DIVERSITY
4. Based on Circadian rhythm: Animals are classified based on the time of day they are more
active. This is related to the circadian clock of animals. They can either be:
1. Diurnal animals: These are animals that are more active during the day. They include
Deer, Cow, Horse and Duck.
2. Nocturnal animals: These are animals that are more active during the night. They include
Tiger, Fox, Owl, Moths etc.

18. ANIMAL DIVERSITY
5. Based on Feeding habit: Style of feeding. These are:
(A) Herbivorous animals: These are animals that feed on grass or other plant
materials. They include Goat, Sheep, Cattle, and Elephant etc
(B) Carnivorous animals: These are generally predacious and feed on animals and
flesh. They include Tiger, Lion, Vulture and Hyena etc
(C) Omnivorous animals: Animals of this category eat all kind of foods. They
include Cockroaches, Domestic dog, Cat and Man.

19. ANIMAL DIVERSITY
5. Based on Feeding habit: Style of feeding. These are:
(A) Herbivorous animals: These are animals that feed on grass or other plant
materials. They include Goat, Sheep, Cattle, and Elephant etc
(B) Carnivorous animals: These are generally predacious and feed on animals and
flesh. They include Tiger, Lion, Vulture and Hyena etc
(C) Omnivorous animals: Animals of this category eat all kind of foods. They
include Cockroaches, Domestic dog, Cat and Man.

20. ANIMAL DIVERSITY
6. Based on mode of Nutrition: Mode of nutrition simply means the feeding mode in
animals. All animals are heterotrophs, holozoic or zootrophic. However, different
animals have distinct feeding styles which are:
(A) Scavengers: They get their food from dead or rotten plants and animals. They can
also feed on discarded organic materials. They include Cockroach, Crow, Vulture and
Hyena etc.
(B) Parasitic: This is a situation where by a smaller animal known as parasite, live in
or outside the host to obtain food and thereby harming it. They include Round worm:
an internal parasite of Human body and Pediculus humanus :an external parasite.
(C) Predators: They are generally bigger, stronger than their prey. They feed on the
prey by attacking or accidental interaction. They kill their hunts and eat their flesh.
They include Tiger, Lion and Wolf, etc.

21. ANIMAL DIVERSITY
6. Based on mode of Nutrition:
Human Louse Predator-prey

22. ANIMAL DIVERSITY
7. Based on the presence or absence of vertebral column: This is also known as
backbone or spine
 It is part of axial skeleton
 Consist series of 33 bones called vertebrae which are separated by intervertebral
discs
 Helps in protection, support, forming central
axis and movement.

23. ANIMAL DIVERSITY
7. Based on the presence or absence of vertebral column:
(A) Invertebrate: These are the animals without backbone. They include earthworms,
Cockroach, Roundworms, etc
(B) Vertebrates: These are animals with backbone. The embryonic notochord of these
animals transform into vertebral column when fully formed. they include, Fishes,
Amphibians, Reptiles, Birds and Mammals.

24. ANIMAL DIVERSITY
8. Based on reproduction and development: Animals are also classified based on their
mode of reproduction. These are:
(A) Sexual reproduction and embryonic development: During sexual
reproduction, the male and female gamete of a specie combined in a
process called fertilization. Fertilization and fusion of the nuclei
produce a zygote

25. ANIMAL DIVERSITY
8. Based on reproduction and development:
(B) Asexual reproduction and embryonic development:
 Binary fission: such as Planarians, Sea anemones, Sea cucumbers
 Budding: such as Hydra and Corals
 Fragmentation: such as Tubbelarians, Cnidarians
 Parthenogenesis/virgin beginning: mostly in invertebrate such as ants,
bees, reptiles. Tubbelarians
Sea cucumbers

26. ANIMAL DIVERSITY
8. Based on reproduction and development:
(C) Hermaphroditism: Individual with both male and female
reproductive characteristics. Such as snails, earthworms, tapeworms.

27. ANIMAL DIVERSITY
9. Based on fertilization:
(A) Internal fertilization
(B) External fertilization

28. ANIMAL DIVERSITY
10. Based on development of embryo/Viviparity:
(A) Oviparous: e.g birds, reptiles
(B) Viviparous: e.g cat, dog, human
(C) Ovoviviparous: e.g snakes

29. ANIMAL DIVERSITY
11. Based on layers of tissues: Animals layering at early stage during
blastula, of their lives. Layers are called germ layers. Based on this, they are classified
into:
(A) Diploblastic: Animal with two germ layers. E.g Jelly fish
(B) Triploblastic: Animal with three germ layers, e.g worms

30. ANIMAL DIVERSITY
11. Based on layers of tissues:

31. ANIMAL DIVERSITY
12. Based on presence or absence of a Coelom:
 This is the body cavity
 A true body cavity is called Coelom
 Cavity is any space that
accommodate organs in animals

32. ANIMAL DIVERSITY
12. Based on presence or absence of a Coelom: Divided into:
 Coelomates animals: Animals with body cavity such as mammals
 Pseudocoelomates animals: Lacks
Muscle layers. Derived from mesoderm
and endoderm. E.g roundworms.
 Acoelomate animals: Lacks body
Cavity e.g flatworms

33. ANIMAL DIVERSITY
13. Based on food they eat:

34. ANIMAL DIVERSITY
14. Based on body temperature:
(A) Homeotherms: Animals that maintain a constant internal body
temperature across a wide range of environmental conditions. Such
as mammals and birds.
(B) Poikilotherms: Animals whose temperature changes depending on the
environmental temperature. Such as Fish, amphibians and most
invertebrate.
(C) Heterotherms: Animals which keeps a constant body temperature, but
have specific periods where their temperature is different such as
during hibernation such as Squirrels and bears

35. ANIMAL DIVERSITY
14. Based on body temperature:
(D) Ectotherms: Animals that receive heat primarily from external
sources such as reptiles.
(E) Endotherms: Animals that create their own heat such as mammals
and birds. (Conduction, Convection and Radiation)

36. ANIMAL DIVERSITY
14. Based on body temperature:

37. ANIMAL DIVERSITY
Phylum:
1. Protozoa
2. Phylum Porifera (Sponges)
3. Cnidarians (Sea anemons)
4. Platyhelminthes (Flatworms)
5. Nematodes (Hook-worms)
6. Annelida (Earthworms)
7. Arthropoda (Spider)
8. Mollusca (Snails)
9. Echinodermata (Sea lilies)
10. Chordata (Man)

38. ANIMAL DIVERSITY
Phylum Porifera (Sponges):
 Have no definite shape – asymmetrical;
 No tissues or organs
 Colony of specialized cells
 Mostly stationary or reliant on water
 No brain
 Open circulatory system
 Filter feeders
 Gaseous exchange is through cell membrane

39. ANIMAL DIVERSITY
Phylum Porifera (Sponges): Classes:
 Class Calcarea – has calcium carbonate spicules
 Class Hexactinellida – glass sponges with spicules of silica
 Class Demospongiae – no spicules, only spongin

40. ANIMAL DIVERSITY
Phylum Porifera (Sponges): Examples:
Barrel sponge Vase sponge
Tube sponge Venus Flower Basket

41. ANIMAL DIVERSITY
Phylum Cnidarians (Sea anemons):
 They include Jellyfishes, corals, anemones
 Formally called Coelentrata
 They are Radial symmetry
 Two body types (medusa and polyp)
 Two simple tissue layer
 Primitive nerve net but no brain
 2-way digestive tract
 Stinging cells for capturing food
 Have open circulatory system
 Use tentacles and waves for movement

42. ANIMAL DIVERSITY
Phylum Cnidarians (Sea anemons): Classes
 Class Hydrozoa – Hydra, Portuguese-Man-of-War, Obelia; mostly
polyp or hydroid stage
 Class Scyphozoa – true jellyfishes; mostly medusa stage
 Class Anthozoa – corals, anemones
 Class Cubozoa – box jellies

43. ANIMAL DIVERSITY
Phylum Cnidarians (Sea anemons): Examples
Moon jelly Sea anemone
Aggregating anemones
Coral reef

44. ANIMAL DIVERSITY
Phylum Platyhelminthes (Flatworms):
 First animals to exhibit bilateral symmetry
 Have primitive brain, but nerve cord
 3 tissue layers
 Includes free-living flatworms and parasitic flatworms
(tapeworms, flukes)
 Mostly flattened, with no body cavity and are usually
parasitic

45. ANIMAL DIVERSITY
Phylum Platyhelminthes (Flatworms):
 Mouth is used for eating and excreting
 Movement achieved by wiggling their body in aquatic
environments
 No respiratory system, No circulatory system

46. ANIMAL DIVERSITY
Phylum Platyhelminthes (Flatworms): Classes:
 Class Turbellaria – free-living flatworms
 Class Cestoda – tapeworms
 Class Trematoda - flukes

47. ANIMAL DIVERSITY
Phylum Platyhelminthes (Flatworms): Examples:
Flatworm Tapeworm head (scolex)
Liver fluke

48. ANIMAL DIVERSITY
Phylum Nematoda (Hook worms):
 They are worm like, with a full body cavity and full digestive system
 Are Bilateral
 Have organ systems
 Brain is circular ring of nerves for brain
 Circulation is by diffusion
 Movement achieved by wiggling their body in aquatic environments
 Full digestive systems

49. ANIMAL DIVERSITY
Phylum Nematoda (Hook worms): Classes:
 Class Adenophprae (Aphasmida): They lack phasmid
(Caudal sensory organ) Such Trichuris
 Class Secerenantea (Phasmida): They have phasmid (Caudal
sensory organ) Such as Wuchereria, Onchocerea etc

50. ANIMAL DIVERSITY
Phylum Nematoda (Hook worms): Example:

51. ANIMAL DIVERSITY
Phylum Annelida (Earthworms)
 They earthworms, sandworms, leeches
 They are known as segmented worms
 Have well-developed digestive system and its One-way
digestive system, also well-developed circulatory systems
 Fully segmented body system
 Bilaterally symmetry
 Small “control centers” with nerves

52. ANIMAL DIVERSITY
Phylum Annelida (Earthworms)
 They have blood vessels with (occasionally) multiple hearts
 They are omnivores or detritivores
 Gills or breathe through skin
 Some have feet, others extend and contract their
body/muscles

53. ANIMAL DIVERSITY
Phylum Annelida (Earthworms) Classes:
 Class Oligochaeta – earthworms, bloodworms; oligo- means
“few” and chaeta means a “bristle” or stout hair
 Class Polychaeta – many bristles and parapodia (fleshly
lobes to “walk” with
 Class Hirudinea – leeches (most are NOT bloodsuckers)

54. ANIMAL DIVERSITY
Phylum Annelida (Earthworms) Examples:
Christmas tree worm Feather-duster worm
Leech

55. ANIMAL DIVERSITY
Phylum Arthropoda (Insects):
 Known as joint-legged animals
 Includes insects, crustaceans, centipedes, millipedes, and
arachnids
 exoskeleton made of chitin
 must shed shell to grow
 Have segmented body system: Head, Thorax and Abdomen

56. ANIMAL DIVERSITY
Phylum Arthropoda (Insects):
 They are bilaterally symmetrical
 Have full brain with nerve cords
 Have open circulatory system
 Respiration is by book lungs and gills
 Have jointed appendages for movement
 Have full digestive system

57. ANIMAL DIVERSITY
Phylum Arthropoda (Insects): Classes
 Class Crustacea – shrimps, lobsters, crabs, crawfishes
 Class Amphipoda – small; called scuds
 Class Isopoda – sea lice; some are parasitic
 Class Stomatopoda – mantis shrimps
 Class Pycnogonida – sea spiders
 Class Merostomata – horseshoe crabs
 Class Cirripedia - barnacles

58. ANIMAL DIVERSITY
Phylum Arthropoda (Insects): Examples
Spider crab /Crustacea Mantis shrimp - Stomatopoda
(thumbsplitter)
Sea spider- Pycnogonida

59. ANIMAL DIVERSITY
Phylum Mollusca (Snails):
 This includes snails, slugs, nudibranchs, chitons, limpets, clams, oysters, squid, octopus,
nautilus, etc
 Either have no shell, one shell, or two shells (Shells made up of protein and calcareous
spicules)
 Have a nervous system with a circum-oesophagal ring, ganglia and paired nerve cords
 Have open circulatory system with a heart and an aorta
 Body have no cavity, but has a though gut with mouth and anus
 Have gaseous exchange organs called etenidial gills
 They are Bilaterally symmetrical, body has more than two cell layers
 Reproduction is usually sexual and found in moist environment

60. ANIMAL DIVERSITY
Phylum Mollusca (Snails): Classes:

61. ANIMAL DIVERSITY
Phylum Mollusca (Snails): Classes:
 Class Gastropoda – snails, slugs, conchs, nudibranchs; have either no shell
or one shell; name means “stomach foot” and are the most diverse group
 Class Bivalvia – clams, oysters, mussels; have two shells that hinge together
and are aquatic. They are filter feeders. They lack distinct head
 Class Polyplacophora – chitons; snail-like with 8 embedded plates on its
back
 Class Cephalopoda – squid, octopus, nautilus, cuttlefish; name means “head
foot”; well-developed nervous system. They are free-swimmers and some
are predators. They have separate sexes

62. ANIMAL DIVERSITY
Phylum Mollusca (Snails): Examples:
Chambered nautilus
Oyster on half-shell
(needs Tabasco)
Sepioteuthis sepioidea
(Squid)
Octopus vulgaris
(Octopus)

63. ANIMAL DIVERSITY
Phylum Echinodermata (Spiney-skinned):
 This includes sea stars, brittle stars, sea urchins, sand dollars, sea cucumbers,
and crinoids
 They reverted back to radial symmetry (radial in adults / bilateral in larvae)
 They have tube feet and water vascular system
 Most exhibit pentamerism
 They are marine organisms
 They posses an endoskeleton of calcareous plates known as Ossicles
 They have no head and no sign of head, also have a ventral mouth
 They are related to chordates from blastospore

64. ANIMAL DIVERSITY
Phylum Echinodermata (Spiney-skinned): Classes:
 Class Asteroidea – sea stars
 Class Ophiuroidea – brittle stars, serpent stars
 Class Echinoidea – sea urchins, sand dollars
 Class Holothuroidea – sea cucumbers
 Class Crinoidea – sea lilies, feather stars

65. ANIMAL DIVERSITY
Phylum Echinodermata (Spiney-skinned): Examples:
Sea star - Asteroidea Bat star - Asteroidea
Pycnopodia - Asteroidea
Sea urchin - Echinoidea
Sand dollar - Echinoidea

66. ANIMAL DIVERSITY
Phylum Chordata (Man):
 Includes fish, amphibians, reptiles, birds, and mammals
 Ha a dorsal hollow nerve tube/cord
 Has Notochord: back string present in all embryo, may be absence/reduced in adults
 Pharyngeal gill slits: Functioning in filter feeders, as gills in fish, as ear lobes in human
 Post anal tail: In human present at embryonic stage and subsequently reabsorbed.

67. ANIMAL DIVERSITY
Phylum Chordata (Man): Classification
 Have four subphyla:
1. The Protochordates: invertebrate chordates
2. Subphylum Urochordata: (Uro=tail, also called tunicates. Their
larvae shows chordate characteristics, but adults have lost many of such
organs) such as sea squirts, salps, and ascidians
3. Subphylum Cephalochordata : (Cepa=Head) which means they
don’t have head, though have all chordate characters, buck lack bones.
They include lancelets
4. Subphylum Vertebrata

68. ANIMAL DIVERSITY
Phylum Chordata (Man): Classification
2. Subphylum Urochordata: (Uro=tail, also called tunicates.
Their larvae shows chordate characteristics, but adults have lost
many of such organs) such as sea squirts, salps, and ascidians

69. ANIMAL DIVERSITY
Phylum Chordata (Man): Classification
3. Subphylum Cephalochordata : (Cepa=Head) which means
they don’t have head, though have all chordate characters, buck
lack bones. They include lancelets
Amphioxus

70. ANIMAL DIVERSITY
Phylum Chordata (Man): Classification
4. Subphylum Vertebrata:
 The skeletal units surrounding the nerve cord
 Have a brain enclosed within a skull
 Have an endoskeleton which will grow along with the animal
 A closed circulatory system with a ventral heart
 Excretion via kidney
 Separate male and female with sexual reproduction in most, with few
cases of pathenogenesis

71. ANIMAL DIVERSITY
Phylum Chordata (Man): Classification
4. Subphylum Vertebrata: Classes:
 Class Agnatha – jawless fishes; lampreys and hagfishes
 Class Chondrichthys – cartilaginous fishes; sharks, rays, skates, chimeras
 Class Osteichthys – boney fishes
 Class Amphibia – frogs, salamanders
 Class Reptila – turtles, snakes, lizards, and crocodilians
 Class Aves – birds
 Class Mammalia - mammals

72. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Agnatha: No jaws, Paired fins and scales. They are ell-shaped
prey for fishes.
(Gnathostomes (Jawed fishes)
Sea lamprey - Agnatha

73. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Chondrichthys: Have internal skeleton of cartilage. Has
single loop gills. They are not complete buoyant. No external ear. Cold
blooded. Fishes. include sharks, rays, skates, chimeras
Tiger shark - Chondrichthys

74. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Osteichthys: 95% to todays fish species. Respiration via
gills. Control full buoyancy. Well developed skeleton with bones. Skin
covered in overlapping scales. They include the Actinoperygli and
Sarcopterygli Clown anemone fish - Osteichthys

75. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Amphibians: They include frogs, newts and salamanders. They
were the first land vertebrate. They undergo metamorphosis. Eggs have no
shell. External fertilization. Respiration is by gills, lungs or skin.
They can be:
Urodela (Tailed) such as Salamander
Anura (Tailless) such as frogs
Apoda (Legless)Caecilians
Bullfrog - Amphibia

76. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Reptila: They are creeping animals. They have scale
and are dry to touch. Have separate sexes. Internal
fertilization. Uses lungs for respiration. They have
amniotyic eggs. They include Turtles, snakes, lizards, and
crocodilians

77. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Reptila: They are classified into:
1. Crocodilla: Includes Alligators, Crocodiles. They are found
in fresh water and can move on land due to their semi-erect
posture.

78. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Reptila: They are classified into:
2. Sphenodontia: They have wedge tooth. They include
Tautara
3. Squamata: They include lizards and snakes. Lizards differs
from snakes by having four limbs, eyelids, external ears.

79. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Reptila: They are classified into:
4. Testudines: They have shell. They include turtles. They
have cartilaginous shell on back. They lay eggs on land

80. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Aves: Are feathered animals
Bones are light weight for flight
They are endothermic. They have advanced
Vision. Undergoes internal fertilization
Have shelled eggs. Mating comes after
An elaborate courtship display. Young birds are often exothermic and needs to
be incubated. They include Osprey

81. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Mammalia: They are mammals.
They have mammary glands.
They have hairs or fur.
They are Homeothermic.
They have integuments:
that serves as temperature regulators.
They include Zebra, rat, cat etc

82. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
 Class Mammalia: Class
1. Monotremes: They lay eggs like reptiles. They don’t have fur and milk.
They include Platypus and Echidna.
2. Marsupials: They have a bag or pouch. The young is immature and crawl
to mothers pouch to continue development. They include Opossums,
Kangaroos, Koalas.
3. Placentals: Young complete embryonic development with in the mother’s
uterus and are nourished across a placenta. They include Man

83. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
Monotremes: Echidna Monotremes: Platypus

84. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
2. Marsupials:

85. ANIMAL DIVERSITY
4. Subphylum Vertebrata: Classes:
3. Placentals:

86. ANIMAL DIVERSITY