1. Multicellular life arose over a billion years ago
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

2. KINGDOM ANIMALIA THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

3. What Is an Animal? Animals
Are eukaryotic, multicellular, heterotrophic organisms that obtain nutrients by ingestion
Digest their food within their bodies
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

4. Most animals reproduce sexually and then proceed through a series of developmental stages
Most animals have muscle cells and nerve cells that control the muscles
Haploid
Sperm
Egg 1 2
Meiosis
Fertilization
Zygote (fertilized egg)
Adult 3
Diploid
Blastula (cross section) 7
Metamorphosis
Digestive tract
Outer cell layer (ectoderm) 4
Primitive gut 6 5
Early gastrula
Larva
Inner cell layer (endoderm)
Later gastrula
Opening
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

5. Early Animals and the Cambrian Explosion
Animals probably evolved from a colonial protist that lived in the Precambrian seas
Digestive cavity
Reproductive
cells
Somatic cells 1
Early colony of protists (aggregate of identical cells) 2
Hollow sphere (shown in cross section) 3
Beginning of cell specialization 4
Infolding 5
Gastrula-like “proto-animal”
Figure 17.4
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

6. At the beginning of the Cambrian period, 545 million years ago, animals underwent a rapid diversification
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

7. Animal Phylogeny
To reconstruct the evolutionary history of animal phyla, researchers must depend on clues from comparative anatomy and embryology
Four key evolutionary branch points have been hypothesized
The first branch point is defined by the presence of true tissues
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

8. 4 3 2 1 Coelom from digestive tube Pseudocoelom True coelom
Sponges
Cnidarians
Flatworms
Roundworms
Mollusks
Annelids
Arthropods
Echinoderms
Chordates
Coelom from cell masses
Coelom from digestive tube 4
Pseudocoelom
True coelom
No body cavity 3
Body cavities
Radial symmetry
Bilateral symmetry 2
True tissues 1
Multicellularity
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

9. (b) Bilateral symmetry
The second major evolutionary split is based partly on body symmetry
(a) Radial symmetry
(b) Bilateral symmetry
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

10. Third, the evolution of body cavities led to more complex animals A body cavity
Is a fluid-filled space separating the digestive tract from the outer body wall
May be a pseudocoelom or a true coelom
Body covering (from ectoderm)
Tissue-filled region (from mesoderm)
Digestive tract (from endoderm)
(a) No body cavity (e.g., flatworm)
Pseudocoelom
Body covering (from ectoderm)
Digestive tract (from endoderm)
Muscle layer (from mesoderm)
(b) Pseudocoelom (e.g., roundworm)
Coelom
Body covering (from ectoderm)
Tissue layer lining coelom and suspending internal organs (from mesoderm)
Digestive tract (from endoderm)
Mesentery
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU
(c) True coelom (e.g., annelid)
THURSDAY 18TH MARCH 2010

11. Fourth, among animals with a true coelom, there are two main evolutionary branches, which differ in embryonic development
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

12. THE KINGDOM ANIMALIA Divided into invertebrates and vertebrates
Invertebrates are animals without backbones and represent 95% of the animal kingdom
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

13. Invertebrates - Sponges
Phylum Porifera
Includes sessile animals once believed to be plants
Lack true tissues
The body of a sponge resembles a sac perforated with holes
Draws water into a central cavity, where food is collected
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

14. Choanocyte in contact with an amoebocyte
Pores
Water flow
Skeleton fiber
Central cavity
Choanocyte
Flagella
Amoebocyte
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

15. Invertebrates - Cnidarians
Phylum Cnidaria
Is characterized by organisms with radial symmetry and tentacles with stinging cells
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

16. The basic body plan of a cnidarian
Is a sac with a gastrovascular cavity
Has two variations: the sessile polyp and the floating medusa
Mouth/anus
Tentacle
Gastrovascular cavity
Tentacle
Mouth/anus
Polyp form
Medusa form
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

17. Examples of polyps are Hydras, sea anemones, and coral animals
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

18. The organisms we call jellies are medusas
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

19. Cnidarians are carnivores that use tentacles armed with cnidocytes, or “stinging cells,” to capture prey
Coiled thread
Tentacle
Capsule
“Trigger”
Cnidocyte
Discharge of thread
Prey
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

20. Invertebrates - Flatworms
Phylum Platyhelminthes
Is represented by the simplest bilateral animals
Includes free-living forms such as planarians
Digestive tract (gastrovascular cavity)
Nerve cords
Mouth
Eyespots
Nervous tissue clusters
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

21. Some flatworms are parasitic
Blood flukes are an example
Tapeworms parasitize many vertebrates, including humans
Head
Reproductive structures
Hooks
Sucker
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

22. Invertebrates - Roundworms
Phylum Nematoda
Includes the most diverse and widespread of all animals
Occurs in aquatic and moist terrestrial habitats
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

23. Roundworms exhibit an important evolutionary adaptation, a digestive tube with two openings, a mouth and an anus
A complete digestive tract can process food and absorb nutrients efficiently
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

24. Invertebrates - Mollusks
Phylum Mollusca
Is represented by soft-bodied animals, but most are protected by a hard shell
Includes snails, slugs, clams, octopuses, and squids, to name a few
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

25. The body of a mollusk has three main parts: a muscular foot, a visceral mass, and a mantle
Reproductive organs
Coelom
Mantle
Kidney
Heart
Digestive tract
Mantle cavity
Radula
Shell
Radula
Anus
Gill
Mouth
Nerve cords
Foot
Mouth
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

26. The three major classes of mollusks are
1. Gastropods, which are protected by a single, spiraled shell
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

27. 2. Bivalves, protected by shells divided into two halves
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

28. 3. Cephalopods, which may or may not have a shell
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

29. Invertebrates - Annelids
Phylum Annelida
Includes worms with body segmentation
Anus
Brain
Main heart
Coelom
Digestive tract
Segment walls
Mouth
Accessory hearts
Nerve cord
Blood vessels
Excretory organ
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

30. There are three main classes of annelids
1. Earthworms, which eat their way through soil
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

31. 2. Polychaetes, which burrow in the sea floor
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

32. 3. Leeches, some of which are parasitic
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

33. Invertebrates - Arthropods
Phylum Arthropoda
Contains organisms named for their jointed appendages
Includes crustaceans, arachnids, and insects
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

34. General Characteristics of Arthropods
Arthropods are segmented animals with specialized segments and appendages
Cephalothorax
Abdomen
Thorax
Antennae (sensory reception)
Head
Swimming appendages
Walking legs
Pincer (defense)
Mouthparts (feeding)
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

35. The body of an arthropod is completely covered by an exoskeleton
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

36. Arthropod Diversity There are four main groups of arthropods
1. Arachnids, such as spiders, scorpions, ticks, and mites
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

37. 2. Crustaceans, such as crabs, lobsters, crayfish, shrimps, and barnacles
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

38. 3. Millipedes and centipedes
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

39. 4. Insects, most of which have a three-part body
Head
Thorax
Abdomen
Hawk moth
Antenna
Forewing
Eye
Mosquito
Paper wasp
Mouthparts
Hindwing
Grasshopper
Damselfly
Water strider
Ground beetle
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

40. Many insects undergo metamorphosis in their development
(a) Larva (caterpillar)
(b) Pupa
(c) Pupa
(d) Emerging adult
(e) Adult
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

41. Invertebrates - Echinoderms
Phylum Echinodermata
Is named for the spiny surfaces of the organisms
Includes sea stars, sand dollars, sea urchins, and sea cucumbers
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

42. Echinoderms Are all marine Lack body segments
Usually have an endoskeleton
Have a water vascular system that facilitates gas exchange and waste disposal
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

43. THE VERTEBRATE GENEALOGY
Vertebrates
Are represented by mammals, birds, reptiles, amphibians, and fishes
Have unique features, including the cranium and backbone
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

44. Characteristics of Chordates
Phylum Chordata
Includes the subphylum of vertebrates
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

45. Other subphyla include the lancelets and tunicates, which share four key chordate characteristics
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

46. The four chordate hallmarks are
A dorsal, hollow nerve cord
A notochord
Pharyngeal slits
A post-anal tail
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

47. Dorsal, hollow nerve cord
Notochord
Brain
Muscle segments
Mouth
Anus
Pharyngeal slits
Post-anal tail
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

48. An overview of chordate and vertebrate evolution
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

49. Lungs or lung derivatives
Chordates
Vertebrates
Tetrapods
Periods
Amniotes
Eras
Cenozoic
Tunicates
Tertiary
Aves (birds)
Lancelets
Mammalia (mammals)
Reptilia (reptiles)
Cretaceous
Amphibia (frogs and salamanders)
Mesozoic
Agnatha (jawless vertebrates, such as lampreys)
Osteichthyes (bony fishes)
Feathers
Jurassic
Chondrichthyes (sharks and rays)
Triassic
Permian
Hair
Carboniferous
Amniotic egg
Devonian
Paleozoic
Legs
Silurian
Lungs or lung derivatives
Ordovician
Jaws
Cambrian
Vertebrae
Precambrian
Ancestral chordate
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

50. Fishes
The first vertebrates probably evolved during the early Cambrian period, about 540 million years ago
These early vertebrates, the agnathans, lacked jaws
Agnathans are represented today by lampreys
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

51. The two major groups of living fishes are the classes
Chondrichthyes or cartilaginous fishes
Osteichthyes or bony fishes
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

52. Cartilaginous fishes have a flexible skeleton made of cartilage
Sharks have a lateral line system sensitive to vibrations in the water
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

53. Bony fishes Have a skeleton reinforced by hard calcium salts
Have a lateral line system, a keen sense of smell, and excellent eyesight
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

54. Amphibians Members of the class Amphibia
Exhibit a mixture of aquatic and terrestrial adaptations
Usually need water to reproduce
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

55. Amphibians Were the first vertebrates to colonize land
Descended from fishes that had lungs and fins with muscles
Lobe-finned fish
Early amphibian
Figure 17.34
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

56. Reptiles Class Reptilia
Includes snakes, lizards, turtles, crocodiles, and alligators
Can live totally on land
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

57. Adaptations for living on land include
Scales to prevent dehydration
Lungs for breathing
The amniotic egg
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

58. Reptiles diversified extensively during the Mesozoic Era
Reptiles are ectotherms that obtain their body heat from the environment
Cold blooded
Reptiles diversified extensively during the Mesozoic Era
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

59. Dinosaurs included the largest animals ever to live on land
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

60. Birds
Class Aves
Evolved during the great reptilian radiation of the Mesozoic era
Evolved the ability to fly
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

61. Bird anatomy and physiology are modified for flight
Bones are honeycombed, which makes them lighter
Some specific organs are absent, which reduces weight
A warm, constant body temperature is maintained through endothermy
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

62. A bird’s wings
Illustrate the same principles of aerodynamics as the wings of an airplane
Airfoil
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

63. Mammals Class Mammalia Two features are mammalian hallmarks
Evolved from reptiles about 225 million years ago
Includes mostly terrestrial organisms
Two features are mammalian hallmarks
Hair
Mammary glands that produce milk and nourish the young
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

64. There are three major groups of mammals
Monotremes, the egg-laying mammals, constitute the first group
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

65. The second group of mammals, marsupials, are the so-called pouched mammals
Most mammals are born rather than hatched and are nurtured inside the mother by an organ called a placenta
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

66. Eutherians are also called placental mammals
Their placentas provide more intimate and long-lasting association between the mother and her developing young than do marsupial placentas
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

67. The Evolution of Primates
Primate evolution
Provides a context for understanding human origins
Primates
Evolved from insect-eating mammals during the late Cretaceous period
Early primates
Were small, arboreal mammals
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

68. The distinguishing characteristics of primates were shaped by the demands of living in trees
Limber shoulder joints
Eyes in front of the face
Excellent eye-hand coordination
Extensive parental care
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

69. Apes, the closest relatives to humans
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

70. The Emergence of Humankind
Humans and apes have shared a common ancestry for all but the last 5–7 million years
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

71. Prosimians Anthropoids Monkeys Apes Chim-panzees Humans Gibbons
Gorillas
Humans
Orangutans
New World monkeys
Old World monkeys
Prosimians (lemurs, lorises, pottos, and tarsiers)
Ancestral primate
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU

72. Some Common Misconceptions
Our ancestors were not chimpanzees or any other modern apes
Chimpanzees and humans represent two divergent branches of the anthropoid tree
THURSDAY 18TH MARCH 2010
Evolution from the start to the pinnacle DR. KOFI OWUSU-DAAKU