Diversity Animalia

7/31/2019 Diversity Animalia

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Animals

What is an Animal? Eukaryotic Multicellular Heterotrophic organisms that

obtain nutrients by ingestion Digest their food within their

bodies..


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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 havebeen hypothesized

1. Presence or absence of true tissues

2. Radial or bilateral symmetry3. Presence or absence of a body cavity

(coelom)

4. Mechanism of coelom formation..


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(a) Radial symmetry

(b) Bilateral symmetry

(a) No body cavity (e.g., flatworm)

Body covering(from ectoderm)

Digestivetract (fromendoderm)

Tissue-filledregion (frommesoderm)

(b) Pseudocoelom (e.g., roundworm)

Pseudocoelom


Bodycovering(fromectoderm)

Muscle layer(frommesoderm)

(c) True coelom (e.g., annelid)

Coelom


Body covering (from

ectoderm)

Tissue layerlining coelomandsuspendinginternal organs(frommesoderm)

Mesentery


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Multicellularity

True tissues

Radial

symmetry Bilateralsymmetry

No bodycavity

Body cavities

PseudocoelomTrue coelom

Coelom fromcell masses

Coelom fromdigestive tube

1

2

3

4

Sponges Cnidarians Flatworms Roundworms Mollusks Annelids Arthropods Echinoderms Chordates


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Phylum Porifera Includes sessile

animals once

believed to beplants

Lack true tissues

Resembles a sac

perforated withholes (pores)

Draws water into

a central cavity,

where food is

collected..

Pores

Water flow

Skeleton fiber

Central cavity

Choanocyte

Amoebocyte

Choanocytein contactwith anamoebocyte

Flagella


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Phylum Cnidaria Characterized by organisms with radial

symmetry and tentacles with stinging cells(cnidocytes)

Sac body plan with a gastrovascular cavity

Do not have true organs

Life cycle includes two body forms: Sessile polyp

Floating medusa..

Mouth/anus

Tentacle

Gastrovascularcavity

Tentacle

Mouth/anus

MedusaPolyp


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Cnidarians are carnivores that use

tentacles armed with cnidocytes, or

stinging cells, to capture prey..

TentacleCoiledthread Capsule

Trigger

Discharge ofthread

Cnidocyte

Prey


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Phylum Platyhelminthes

Is represented by the simplest bilateralanimals

Have true organs but no body cavity acoelomate

Digestive tract is two directional only oneopening = incomplete digestive tract

Includes free-living forms such asplanarian

Includes many parasitic forms such astapeworms


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Digestive tract(gastrovascularcavity) Nerve cords

Mouth

Eyespots

Nervous tissueclusters


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Reproductivestructures

Head

Hooks

Sucker


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Phylum Nematoda

exhibit an important evolutionary adaptation;

a digestive tube with two openings, a mouthand an anus

A complete digestive tract can process food and

absorb nutrients efficiently

Only phylum with a pseudocoelom..


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Phylum Mollusca

Is represented by soft-bodied animals, butmost are protected by a hard shell

All have a similar body plan:

Muscular foot; maybe modified into tentacles for

locomotion and defense and food gathering

Mantle secretes shell and aids in respiration

Visceral mass containing internal organs

First group with a true coelom eucoelomates..


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Mantle

Mantlecavity

Shell

Anus

Gill

FootNerve cords

Visceral mass

Kidney

Coelom

Heart

Reproductiveorgans

Digestivetract

RadulaRadula

Mouth

Mouth


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Phylum Annelida

Includes worms with body segmentation

division of the body along into length into aseries of repeated segments; look like rings

Skin surface used for gas exchange


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Phylum Arthropoda

All have exoskeleton of chitin

Appendages are jointed

Appendages are highly specialized for the

environment

Undergo metamorphosis change in bodyform during development

This is the largest group of animals

Includes insects most abundant animals..


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Metamorphosis = egg larva pupa adult..


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Phylum Echinodermata

Is named for the spiny surfaces of the

organisms

Have endoskeleton

Have water-vascular system hydraulic

pumps that circulate water for gas-exchange,

waste disposal, circulation of nutrients, andlocomotion with tube feet

All aquatic..


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Muscle segments

Post-analtail

Notochord

Anus

Dorsal,hollow nervecord

Pharyngealslits

Brain

Mouth

Phylum Chordata all possess these

characters at some point during

development Have notochord = supporting rod of tissue; becomes

vertebrae in one subphylum

Have dorsal, hollow nerve cord

Have post-anal tail Have pharyngeal pouches..

Ch d t


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Eras

Cenoz

oic

Mesozoic

Paleozoic

Precam

brian

Tertiary

Cretaceous

Jurassic

Tria

ssic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Tunicate

s

Lancelets

Agnatha

(jawlessvertebrate

s,

suchaslamprey

s)

Chondrichth

yes(sharksandray

s)

Osteic

hthyes(bonyfishes)

Amphibia(frogsan

d

salamanders)

Reptilia(reptiles)

Aves

(birds)

Mammalia

(mammals)

Ancestral chordate

Vertebrae

Jaws

Lungs or lung derivatives

Legs

Amniotic egg

Hair

Feathers

Chordates

Vertebrates

Tetrapods

Amniotes

Periods

Chordate Evolution


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The subphyla include the invertebrate

chordates lancelets (cephalochordata)

and tunicates (urochordata), which alsoshare four key chordate characteristics..


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This phylum includes the subphylum

Vertebrata

The notochord develops into the vertebralcolumn..


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The first three major classes of the

phylum are fishesAgnatha jawless fishes, eg.

lampreys

Chondrichthyes cartilage fishes

Osteichthyes bony fishes..


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Cartilaginous fishes have a flexible

skeleton made of cartilage; the only bone

is found in the jaw

Includes sharks, rays


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Bony Fish

Have a skeleton reinforced by hard

calcium salts Have a lateral line system, a keen sense of

smell, and excellent eyesight

Most bony fishes are ray-finned fishes

A second evolutionary branch includes

lungfishes and lobe-finned fishes..


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Terrestrial vertebrates are

collectively calledtetrapods, which means

four legs

Class Amphibia Exhibit a mixture of aquatic

and terrestrial adaptations

Usually need water toreproduce..


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Class Reptilia - can live totally on land

Have scales to prevent dehydration

Have claws for digging and protection Have lungs for breathing

First group to develop the amniotic egg..


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Class Aves

Evolved the ability to fly and only animals

with feathers

Bird anatomy and physiology are modified for

flight Bones are honeycombed, which makes them

lighter

Some specific organs are absent, whichreduces weight

A warm, constant body temperature is

maintained through endothermy..


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Airfoil


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Class Mammalia

Includes mostly terrestrial organisms Have hair

Have mammary glands that produce milk

and nourish the young

There are three major groups of mammals

Monotremes lay eggs

Marsupials do not have a placenta

Eutherians (placental mammals) have

placenta to nourish young inside mothers

body..


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