Bio 100 Chapter 19

Chapter 19Evolution of

AnimalsLecture Outline

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Animals have distinctive characteristics

Animals are multicellular eukaryotes

Heterotrophs – must acquire nutrients from an external source

Usually reproduce sexually

Many animals have Muscles & Nerves Search actively for food Seek mates, shelter, suitable climate

19-2

3 Types of Symmetry in Animals

3 Types of symmetry Asymmetry – no particular body shape

Sometimes sessile – attached to substrate Exs: sponges

Radial – organized circularly

Exs: jellyfish, starfish

Bilateral – right and left halves Cephalization – head region (brain) Exs: mammals, insects

19-3

19-4

Symmetry & Anatomical Terms

radial symmetry bilateral symmetry

posterior

anterior

dorsal

ventral

19.4 Phylum Porifera: Sponges

Sponges Only Animals without true tissues Asymmetrical body plan

Body is perforated by pores Filter feeder

19-5

Figure 19.4 Sponge anatomy (Cont.)

19-6


Sponge organization collar cell (choanocyte)

flagellum

spicule

pore

amoeboid cell

epidermal cell

amoeboidcellnucleus

H2O inthroughpores

osculum H2O out

centralcavity

collarsponge wall

19.5 Phylum Cnidaria Phylum Cnidaria – most in the sea

Radial symmetry. Polyp (mouth pointed up) & Medusa (mouth pointed down) body forms

Capture their prey with a ring of tentacles that have specialized stinging cells, cnidocytes

Incomplete digestive tract (one opening)

Exs: jellyfish, sea anemone

19-7

Figure 19.5A Cnidarian diversity

19-8

Phylum: Platyhelminthes

Phylum Platyhelminthes = Flatworms Bilateral symmetry

Have 3 germ layers Ectoderm from which body wall develops Endoderm from which digestive cavity develops Mesoderm which contributes to organ formation

19-9

Flatworm Ex.: Planarians

Digestive System – incomplete (only 1 opening),

undigested food exits through pharynx (mouth is in middle of body)

Reproductive System – Hermaphrodites (both male and female sex organs) and perform cross-fertilization (when two flatworm mate, each is fertilized and fertilizes the other)

19-10

Figure 19.6 Planarian anatomy (Cont.)

19-11


auricle eye spots

5 mmsense organs© Tom E. Adams/Peter Arnold/Photolibrary

19.7 Some flatworms are parasitic

Tapeworms Endoparasites (internal parasites) of various vertebrates

Scolex (head region) bears hooks and suckers for attachment to the intestinal wall of the host

Flukes Endoparasites of various vertebrates

Anterior end of the animal has an oral sucker and at least one other sucker used for attachment to the host

19-12

Figure 19.7A Tapeworm (Taenia solium) anatomy and life cycle

19-13


Bladder worm attachesto human intestinewhere it matures into atapeworm. As the tapeworm grows, proglottids mature, and eventually fill with eggs.

1.0 mm250 μm

hooks

sucker scolex proglottid

(left): © James Webb/Phototake; (right): © John D. Cunningham/Visuals Unlimited

19.8 Body Cavity = Coelom

One defining characteristic in animals is the presence or absence of a body cavity or coelom Flatworms do not have any body cavity Roundworms have a pseudocoelom

Body cavity incompletely lined by mesoderm Mesoderm lines only the body wall

Molluscs, annelids, arthropods, echinoderms and chordates have a true coelom Body cavity completely lined by mesoderm Mesoderm lines both the body wall and the digestive tract

19-14

Figure 19.8 Body cavities

19-15


Acoelomate (flatworms) Pseudocoelomate (roundworms) Coelomate (molluscs, annelids, arthropods,echinoderms, chordates)

endoderm mesoderm

pseudocoelom endoderm mesoderm

digestive cavity ectoderm

coelom mesentery mesoderm

ectodermdigestive cavityendodermdigestive cavity ectoderm

19.9 Phylum Mollusca

All Molluscs have a body composed of Foot – strong, muscular portion used for locomotion Visceral Mass – soft-bodied portion that contains

internal organs Mantle – covering that envelops the visceral mass

May secrete an exoskeleton called a shell

Rasping, tonguelike radula Bears many rows of teeth and is used to obtain food

3 common groups Gastropods, cephalopods, and bivalves

19-16

Figure 19.9B Three groups of molluscs

Gastropods Meaning

stomach-footed

Includes snails

Animal moves

by muscle contractions that pass along its ventrally flattened foot

19-17

19.9 Molluscs have a

three-part body plan


eyes

growth linefoot

spiral shell

tentaclegills

footmantle

Three-stripedorisnudibranch

Land snail

(nudibranch): © Kenneth W. Fink/Bruce Coleman, Inc

1 Gastropods

Figure 19.9B Three groups of molluscs (Cont.)

Cephalopods (meaning head-footed) including octopuses, squids, and nautiluses Foot has evolved into tentacles about the head

19-18


(nautilus): © Douglas Faulkner/Photo Researchers, Inc

2

arm

eye

suckers

Two-spotted octopusCephalopods

Chambered nautilus

shell

tentacles

eye

Figure 19.9B Three groups of molluscs (Cont.)

Bivalves (shells have two part) including clams, oysters, scallops, and mussels Clam is a filter feeder and food particles and water enter the mantle cavity by way of a siphon

19-19


(scallop): Courtesy Larry S. Roberts (mussel): © Fred Whitehead/Animals Animals;

growth linesof shell

Blue mussel

3

tentacleson mantle

shelleyes

Bivalves

Bay scallop

19.10 Phylum Annelida: Segmented worms

Segmentation can be seen externally by the rings that encircle the body

Complete digestive tract

Exs: Earthworms & Leeches

19-20

19-21

Figure 19.10A Earthworm anatomy


dorsal blood vessel

nephridium

pharynx

mouthesophagus

brain

coelomhearts (5pairs)

seminal vesicle

ventral blood vessel

ventral nerve cord

clitellum

anus

crop

Figure 19.10B Other annelids (Cont.)

19-22


c. Medicinal leech

anterior sucker

Posteriorsucker

© St. Bartholomews Hospital/SPL/Photo Researchers, Inc.

Phylum Nematoda: Roundworms

Roundworms = Nematodes

Nonsegmented

Free-living and parasitic species

Exs: Pinworms & Hookworms

19-23

Figure 19.11A Ascaris

19-24

Figure 19.11B Encysted Trichinella larva.


SEM 400x

cyst

© James Solliday/Biological Photo Service

Phylum: Arthropoda

Extremely diverse – more than 1 million species

Six characteristics1.Jointed appendages

2.Exoskeleton

3.Segmentation

4.Well-developed nervous system

5.Adaptation of respiratory organs

6.Reduced competition through metamorphosis

19-25

Figure 19.12A Exoskeleton and jointed appendages of a crayfish

19-26


AbdomenCephalothorax

antennule

antennacompound

eyetelson

anusgills

mouth

uropods

first walking leg(pinching claw)

second walking leg

third walking leg

fourth walking leg

fifth walking leg

swimmerets

Figure 19.12B Monarch butterfly metamorphosis

19-27


Caterpillar, eating stage Pupa, cocoon stage Metamorphosis occurs Emergence of adult Butterfly, adult stage

(all): © John Shaw/Tom Stack & Associates

19.13 Arthropods are diverse

Crustaceans Largely marine arthropods that include crabs,

barnacles, shrimps, and crayfish Head usually bears a pair of compound eyes and five

pairs of appendages

Centipedes and millipedes Centipedes – pair of appendages on every segment Millipedes – 2 pairs of appendages on most segments

19-28

Figure 19.13A Crustacean diversity

19-29


(crab): © Michael Lustbader/Photo Researchers, Inc

legs (5 pairs)

mouth

Sally light foot crab

eye

Figure 19.13B Centipede and millipede

19-30


legs

antenna

Centipede

Millipede

antenna

legs

(centipede): © David M. Dennis/Animals Animals; (millipede): © Geof de Feu/Imagestate

19.13 Arthropods are diverse

Arachnids include spiders, scorpions, ticks, mites, and harvestmen

Spiders have four pairs of legs

Scorpions are the oldest terrestrial arthropods

Ticks and mites are parasites

19-31

Figure 19.13C A spider and two of its relatives

19-32


Black widow spider

Horseshoe crab

compound eye

Giantscorpion

cephalothorax

walking legs

abdomen

pedipalp

stinger

telson

abdomen cephalothorax

(scorpion): © Tom McHugh/Photo Researchers, Inc.; (horseshoe crab): © Jana R. Jirak/Visuals Unlimited; (spider): © Ken Lucas

Figure 19.14 Insect diversity (Cont.)

19-33


antennae

chewingmouthparts

Grasshopper

Leathery forewingscover membranoushindwings

© Chris Mattison/Frank Lane Picture Agency/Corbis

Figure 19.14 Insect diversity (Cont.)

19-34


Butterfly

scale-coveredwings

suckingmouthparts

© McDonald Wildlife Photography/Animals Animals

19.15 Phylum Echinodermata

Radial symmetry as adults

Move using a water vascular system (take in water through sieve plate and pumping into tube feet, when foot touches surface, center withdraws and causes suction-alternate this to move)

Ex: Sea stars, Sea Urchins & Sand Dollars

19-35

Figure 19.15 Echinoderm structure and diversity

19-36

digestivegland tube feet

skin gill

anusstomach

sieve plate

arm

endoskeletal plates

eyespot

ampulla

coelom

gonad


Figure 19.15 Echinoderm structure and diversity (Cont.)

19-37Seaurchin

spines


© Randy Morse/Animals Animals

Figure 19.15 Echinoderm structure and diversity (Cont.)

19-38

Sand dollar


© Andrew J. Martinez/Photo Researchers, Inc.

19.16 Phylum Chordata

Simple Chordates Exs: Lancelet & Tunicate

4 characteristics1. Dorsal supporting rod (notochord)

2. Dorsal tubular nerve cord

3. Pharyngeal pouches (become gills, in humans become part of the ear)

4. Postanal tail

19-39

Figure 19.17A The invertebrate chordates

19-40a: © Heather Angel/Natural Visions; b: © Rick Harbo

a.Tunicate b.Lancelet


Figure 19.17B Phylogenetic tree of the chordates

19-41


* includes birds

Lancelets

Tunicates

Jawless Fishes

Cartilaginous Fishes

Ray-finned Fishes

Lobe-finned Fishes

Amphibians

Reptiles*

Mammals

ancestralchordate

vertebrae

jaws

bonyskeleton

lungs

limbs

amniotic egg

mammary glandcommon ancestor

Ch

ord

ates

Am

nio

tes

Tet

rap

od

s

Gn

ath

ost

om

es

Ver

teb

rate

s

19.18 Jaws, a bony skeleton, and lungs evolved among the fishes

Jawless Fishes (Class Agnatha) Smooth, scaleless skin, no jaws or paired fins

Cartilaginous Fishes (Class Chondrichthyes) sharks & rays Skeletons of cartilage instead of bone

Bony Fishes (Class Osteichthyes)

Ray-finned fishes

19-42

Figure 19.18B Diversity of fishes

19-43


toothed oral disk

gill slits (seven pairs)

Lamprey, a jawless fish

(lamprey): © Heather Angel/Natural Visions


19-44


dorsal fingill slits

jaw with teeth

pectoral fin

sand tiger shark, a cartilaginous fish

(shark): © James Watt/Animals Animals


19-45


operculumpectoral finSoldier fish, a bony fish

anal finpelvicfin

caudal fin second dorsal fin first dorsal fin

(bony fish): © Ron & Valerie Taylor/Bruce Coleman, Inc.

19.19 Amphibians

Class Amphibia Means living on both land and in the water Represented by frogs, toads, newts, and salamanders Characteristics

Adults have small lungs – air enters the mouth by way of nostrils

Respiration is supplemented by gas exchange through the smooth, moist, skin

Most members lead an amphibious life Larval stage lives in water, and adult stage is on land

19-46

Figure 19.19 Frogs and salamanders are well-known amphibians

19-47


Tree frog hindlimb Barred tiger salamander fleshy toes

hindlimb (to side)tympanum eye moist, smooth skin

(frog): © Joe McDonald/Visuals Unlimited; (salamander): © Suzanne L. Collins & Joseph T. Collins/Photo Researchers, Inc.

19.20 Reptiles

Class Reptilia Exs: Alligators, crocodiles, turtles, snakes, & lizards

Body is covered with hard scales for protection

Fertilization is internal, and the female lays leathery, flexible, shelled eggs

Ectotherms: “cold-blooded”

19-48

Figure 19.20A Reptilian diversity (Cont.)

19-49


venom gland

fang

rattle

Diamondback rattlesnake(rattlesnake): © Joel Sartorie/National Geographic/Getty Images

Figure 19.20A Reptilian diversity (Cont.)

19-50

tail

American alligator

nostriltongue

thick, scaly skin

(alligator): © OS21/PhotoDisc/Getty RF


19.20 Class Aves = Birds

Birds Characterized by the presence of feathers

Birds are adapted to fly Forelimbs are modified as wings Hollow, light bones Horny beak has replaced jaws with teeth 4 chambered heart Endotherms – generate internal heat

19-51

19.21 Mammals

Characteristics of mammals:

Hair: for insulation

Mammary glands to nurse their young

19-54

19.21 Mammals have hair and mammary glands

Monotremes Egg – laying mammals Exs: platypus

Marsupials Begin their development inside the female’s body, but

they are born in a very immature condition Newborns crawl up into a pouch on their mother’s

abdomen Exs: koala

19-55

Figure 19.21A Monotremes and marsupials

19-56© Fritz Prenzel/Animals Animals

a. Duckbill platypus,a monotreme of Australian streams


Figure 19.21A Monotremes and marsupials (Cont.)

19-57


© Stephen J. Krasemann/Getty Images

b. Virginia oppossum, the only American marsupial

Placental mammals

Placenta Organ of exchange between maternal blood and fetal blood

Some groups Ungulates – hoofed mammals – horses, rhinos Carnivores – dogs, cats Primates – monkeys, gorillas, humans Cetaceans – whales and dolphins Chiroptera – bats Rodents – mice, rats, porcupines

19-58

Figure 19.21B Placental mammals

19-59


White-tailed deer,a forest dwelling ungulate

© Stephen J. Krasemann/Photo Researchers, Inc

Connecting the Concepts:Chapter 19

Animals differ in complexity.

Animals acquire food in diverse ways

Progression from the multicellular level of organization to the tissue level, to the organ level, and finally to the organ system level

19-60

Bio 100 Chapter 19

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