17 Lecture Presentation PC 2.ppt - Professor Welday's...

© 2013 Pearson Education, Inc.Lectures by Edward J. Zalisko

PowerPoint® Lectures forCampbell Essential Biology, Fifth Edition, and

Campbell Essential Biology with Physiology,

Fourth Edition– Eric J. Simon, Jean L. Dickey, and Jane B. Reece

Chapter 17Chapter 17The Evolution of Animals

1

THE ORIGINS OF ANIMAL DIVERSITY

• Animal life began in Precambrian seas with the

evolution of multicellular creatures that ate other

organisms.

© 2013 Pearson Education, Inc.

2

What Is an Animal?

• Animals are

– eukaryotic,

– multicellular,

– heterotrophic organisms that obtain nutrients by ingestion, and

– able to digest their food within their bodies.


3

Figure 17.1 4

• Animal cells do not have

– cell walls that provide strong support in the bodies of plants and fungi.

• Most animals have

– muscle cells and

– nerve cells that control the muscles.

What Is an Animal?


5

• Most animals

– are diploid,

– reproduce sexually, and

– proceed through a series of typically similar developmental stages.

What Is an Animal?


6

Figure 17.2

MEIOSIS

Sperm

Egg

Adult

Key

Haploid (n)

Diploid (2n)

FERTILIZATION

MITOSIS

METAMORPHOSIS

Zygote(fertilized egg)

Eight-cell stage

Blastula(cross section)

Digestive tract

Outer cell layer(ectoderm)

Larva

Inner cell layer(endoderm)

Internal sac Later gastrula(cross section)

Future middlelayer of cells(mesoderm)

Early gastrula(cross section)

1

2

3

8

4

7

6

5

7

Figure 17.2a-1

Key

Haploid (n)

Diploid (2n)

MEIOSIS

Sperm

Egg

Adult

1

8

Figure 17.2a-2

Key

Haploid (n)

Diploid (2n)

MEIOSIS

Sperm

Egg

Adult

1

FERTILIZATION


2

9

Figure 17.2a-3

Key

Haploid (n)

Diploid (2n)

MEIOSIS

Sperm

Egg

Adult

1

MITOSIS

FERTILIZATION


Eight-cell stage

2

3

10

Figure 17.2a-4

Key

Haploid (n)

Diploid (2n)

MEIOSIS

Sperm

Egg

Adult

1

MITOSIS

FERTILIZATION


Eight-cell stage

Blastula(cross section)

2

3

4

11

Figure 17.2b-1

Key

Haploid (n)

Diploid (2n)

4

5

Blastula

(cross section)

Early gastrula

(cross section)

12

Figure 17.2b-2

Key

Haploid (n)

Diploid (2n)

4

5

6

Blastula

(cross section)

Outer cell layer

(ectoderm)

Inner cell layer

(endoderm)

Internal sacLater gastrula

(cross section)

Future middle layer

of cells (mesoderm)

Early gastrula

(cross section)

13

Figure 17.2b-3

Key

Haploid (n)

Diploid (2n)

4

5

6

7

Larva

Digestive tract

Blastula

(cross section)

Outer cell layer

(ectoderm)

Inner cell layer

(endoderm)


(cross section)

Future middle layer

of cells (mesoderm)

Early gastrula

(cross section)

14

Figure 17.2b-4

Key

Haploid (n)

Diploid (2n)

METAMORPHOSIS

8

4

5

6

7

Adult

Larva

Digestive tract

Blastula

(cross section)

Outer cell layer

(ectoderm)

Inner cell layer

(endoderm)


(cross section)

Future middle layer

of cells (mesoderm)

Early gastrula

(cross section)

15

Early Animals and the Cambrian Explosion

• Scientists hypothesize that animals evolved from a

colonial flagellated protist.

• The oldest animal fossils found are 550–575

million years old.

• The molecular data suggest a much earlier origin

for animals.


16

Figure 17.3 17

• Animal diversification appears to have accelerated

rapidly from 525-535 million years ago, during the

Cambrian period.

• Because so many animal body plans and new

phyla appear in the fossils from such an

evolutionarily short time span, biologists call this

episode the Cambrian explosion.



18

• The Cambrian explosion may have been ignited by

– increasingly complex predator-prey relationships and/or

– an increase in atmospheric oxygen.

• The genetic framework for complex bodies, a set of

“master control” genes, was already in place.



19

Figure 17.5 20

Animal Phylogeny

• Biologists categorize animals by

– “body plan,” general features of body structure and,

– more recently, genetic data.

• One major branch point distinguishes sponges

from all other animals because, unlike more

complex animals, sponges lack true tissues.


21

Figure 17.6

Ancestralprotist

No true tissues

Radial symmetry

Tissues

Bilateral symmetry

Sponges

Cnidarians

Molluscs

Flatworms

Annelids

Roundworms

Arthropods

Echinoderms

Chordates

22

• A second major evolutionary split is based on

body symmetry.

– Radial symmetry refers to animals that are identical all around a central axis.

– Bilateral symmetry exists where there is only one way to split the animal into equal halves.

Animal Phylogeny


23

Figure 17.7

Radial symmetry

Bilateral symmetry

24

• Animals also vary according to the presence and

type of body cavity, a fluid-filled space separating

the digestive tract from the outer body wall.

Animal Phylogeny


25

Arthropods

• Arthropods (phylum Arthropoda) are named for

their jointed appendages.

• There are over 1 million arthropod species

identified, mostly insects.

• Arthropods are a very diverse and successful

group, occurring in nearly all habitats in the

biosphere.


52

• There are four main groups of arthropods:

1. arachnids,

2. crustaceans,

3. millipedes and centipedes, and

4. insects.

Arthropods


53

Figure 17.18

MAJOR GROUPS OF ARTHROPODS

Arachnids

Crustaceans

Millipedes and Centipedes

Insects

54

General Characteristics of Arthropods

• Arthropods are segmented animals with

– specialized segments and

– appendages for an efficient division of labor among body regions.


55

General Characteristics of Arthropods

• The body of arthropods is completely covered by an exoskeleton, an external skeleton that provides

– protection and

– points of attachment for the muscles that move appendages.


56


Video: Lobster Mouth Parts

57

Figure 17.19

AbdomenCephalothorax

(head and thorax)

Swimmingappendage

Antenna(sensory reception)

Eyes on movable stalks

Mouthparts (feeding)

Walking leg

Walking legs

Pincer (defense)

58

• Arachnids

– usually live on land,

– usually have four pairs of walking legs and a specialized pair of feeding appendages, and

– include spiders, scorpions, ticks, and mites.

Arachnids


59

Figure 17.20

Pair of feedingappendages

Leg (four pairs)

Spider Wood tick

Dust miteScorpionPair of silk-spinningappendages

60

• Crustaceans

– are nearly all aquatic,

– have multiple pairs of specialized appendages, and

– include crabs, lobsters, crayfish, shrimp, and barnacles.

Crustaceans


61

Figure 17.21

Two feedingappendages

Leg (three or more pairs)

Antennae

BarnaclesCrayfish

Pill bug

Shrimp

Crab

62

• Millipedes and centipedes have similar segments

over most of the body.

• Millipedes

– eat decaying plant matter and

– have two pairs of short legs per body segment.

• Centipedes

– are terrestrial carnivores with poison claws and

– have one pair of short legs per body segment.

Millipedes and Centipedes


63

Figure 17.22

One pair of legs per segment

Two pairs of legsper segment

Millipede Centipede

64

• Insects typically have a three-part body

consisting of

1. head,

2. thorax, and

3. abdomen.

Insect Anatomy


65

Figure 17.23

Antenna

Head Thorax Abdomen

Eye

Mouthparts

66

• The insect head usually bears

– a pair of sensory antennae and

– a pair of eyes.

• The mouthparts are adapted for particular kinds of

eating.

• Flight is one key to the great success of insects.

Insect Anatomy


67

• Insects outnumber all other forms of life combined

in terms of species diversity.

• Insects live in

– almost every terrestrial habitat,

– fresh water, and

– the air.

Insect Diversity


68

Figure 17.24

Rhinoceros beetle

Praying mantisRed-and-black-striped stink bug

Jeweled beetle Buckeye butterfly

Trilobite beetle

Greater arid-land katydid

Rainbow bush locust

69

• Many insects undergo metamorphosis in their

development.

• Young insects may

– appear to be smaller forms of the adult or

– change from a larval form to something much different as an adult.

Insect Diversity


70

Figure 17.25

The larva spends itstime eatingand growing.

After severalmolts, the larvabecomes a pupa.

Larval organsbreak downand adultorgans develop. The adult

emerges fromthe cocoon.

The butterflyflies off andreproduces.

71

VERTEBRATE EVOLUTION AND DIVERSITY

• Vertebrates have unique endoskeletons

composed of

– a cranium (skull) and

– a backbone made of a series of bones called vertebrae.


75

Figure 17.27

Vertebra

Cranium(protects brain)

76

• Chordates consists of three groups of

invertebrates:

1. lancelets are bladelike animals without a cranium,

2. tunicates, or sea squirts, also lack a cranium, and

3. hagfishes are eel-like forms that have a cranium.

• All other chordates are vertebrates.

Characteristics of Chordates


80

Figure 17.29

Mouth

Tail

Lancelet Tunicates

81

• An overview of chordate and vertebrate evolution

Characteristics of Chordates


82

Figure 17.30

Ancestralchordate

Tunicates

Lancelets

Hagfishes

Lampreys

Cartilaginousfishes

Bony fishes

Amphibians

Reptiles

Mammals

Ch

ord

ate

s

Verte

bra

tes

Tetra

po

ds

Am

nio

tes

83

Fishes

• The first vertebrates were aquatic and probably

evolved during the early Cambrian period, about

542 million years ago. They

– lacked jaws and

– are represented today by lampreys.


84

Figure 17.31

(a) Hagfish(b) Lamprey (inset: mouth)

(c) Shark, a cartilaginous fish

(d) Bony fish

Lateral line Operculum

85

• The two major groups of living fishes are the

1. cartilaginous fishes (sharks and rays), with a flexible skeleton made of cartilage, and

2. bony fishes, with a skeleton reinforced by hard calcium salts.

• Bony fishes include

– ray-finned fishes and

– lobe-finned fishes.

Fishes


86

• Cartilaginous and bony fishes have a lateral line system that detects minor vibrations in the water.

• To provide lift off the bottom,

– cartilaginous fish must swim but

– bony fish have swim bladders, gas-filled sacs that help them be buoyant.

Fishes


87

Amphibians

• Amphibians

– exhibit a mixture of aquatic and terrestrial adaptations,

– usually need water to reproduce, and

– typically undergo metamorphosis from an aquatic larva to a terrestrial adult.


88

Figure 17.32

Gray tree frog tadpole

Malaysian horned frog

Gray tree frog

Texas barred tiger salamander

89

• Amphibians

– were the first vertebrates to colonize land and

– descended from fishes that had

– lungs,

– fins with muscles, and

– skeletal supports strong enough to enable some

movement on land.

Amphibians


90

Figure 17.33

Lobe-finned fish

Early amphibian

91

• Terrestrial vertebrates are collectively called

tetrapods, which means “four feet.”

• Tetrapods include

– amphibians,

– reptiles, and

– mammals.

Amphibians


92

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