Architectural Pattern of an animal

Chapter 9

What is an animal?

Levels of organization and organismal complexity

• 5 major levels of complexity

• Unicellular• Metazoan?• Tissue• Organ• Organ systems

Levels of organization and organismal complexity

• Protoplasmic– Found in unicellular

organisms– Life functions are

confined to a single cell

– Contains organelles with specific functions

• Cellular– Cell aggregations with

functional differentiations

– Division of labor; nutrition, reproduction

– Not yet tissues!– Ex. volvox

Protoplasmic

• Euglena• Paramecium

Levels of organization and organismal complexity

• Cell-tissue – Similar cells are found

in layers– sponges/ jellyfish– Contains organelles

with specific functions– Ex. Cnidarian nerve

net ( functions in coordination)

• Tissue-organ– More than one tissue

type working together to have a more specialized function

– Flatworms– Ex. Eyespots/

reproductive system

Cell-tissue

Sponges

Jelly fish

Tissue-organ

gutendodermpharynx

parenchymamesoderm

ciliated epidermisectoderm

nerve cordectoderm

muscle layersmesoderm

Three Basic Tissuesectodermmesodermendoderm

epidermisectoderm

Levels of organization and organismal complexity

• Organ-system– Organs work together

to perform some function

– Organ systems– Ex circulation,

respiration– Most animal phyla

Organ Systems of an Earthworm

Organ system

Organ system

pierce-&-suck carnivores - chelicera are poison fangs

Animal tissue types

• What is a tissue?• A cooperative unit of many very similar

cells that perform a specific function.• Examples

– Epithelial– Connective– Muscle– Nervous

Epithelial tissue

• Covers and lines the body and its parts• One surface free, the other bound to

basement membrane• Tissues are named by

– Shape of cells– Number of layers of cells

Epithelial tissue

• Simple= single layer• Stratified = multiple layers• Squamous = flat (tiles)• Cuboudal = like dice• Columnar = like bricks

HickmanFig 9.3

Simple SquamousSimple Cuboidal

Lines the lungsIn the kidney tubules

HickmanFig 9.4

Stratified Squamous Epithelium

Lines the esophagus

HickmanFig 9.4

Ciliated columnar epithelium

Lines the air ways in the respiratory system

HickmanFig 9.5

Connective tissue• Binds other tissues an provides support

matrices• Few cells in a nonliving matrix (ground

substance)• Three fiber types

– Collagen fibers– Elastic fibers– Reticular fibers

• Fibroblasts - cells that produce connective tissue

Loose connective tissue(Areolar)

Holds other tissue in placeA “binding” material

CampbellFig 20.5A

Other Connective tissues

Loose

Adipose

Blood

Fibrous connective

Cartilage

Bone

HickmanFig 9.6

Bone Tissue

• Osteocytes• Haversian canal• Lamelle (matrix)

CampbellFig 20.5D

Bone Development

Muscle tissue• Functions in movement• Bundles of long cells ( muscle fiber= muscle cell)

• Skeletal muscle– Attached to bones by tendons, produces voluntary

movement– Striated unbranched

• Smooth muscle– Found in walls of digestive tract, produces involuntary

movements– Unstriated, spindle shaped

• Cardiac Muscle– Striated , branched, produces heartbeat

Muscle tissueCampbell 20.6

Smoothmuscle

Skeletalmuscle

Cardiacmuscle

Nervous Tissue• Responsible for coordinating body activties• Neurons are nerve cells• Motor neurons are nerves that activate

muscles• Compsed of cell body and dendrites• Supported by glial cells

HickmanFig 9.8

Nervous TissueHickmanFig 9.8

Types of animal symmetry

• Radial• Bilateral• Apparent bilateral

Apparent Radial Symmetrycompare Hickman Fig. 9-10

like spokes of a wheel

sea star

Bilateral symmetry

• cephalized– sensory organs concentrated in head

• body directions:

Radial symmetry

• Radial symmetry-– Mirror images around

a central axis– Figure 9.10

Body Cavities

• Groupings according to presence or type of body cavity

• Coelom - major innovation in bilaterally symmetric animals

• Tube within a tube arrangement

Body Cavities

• Advantages• Flexibility for crawling and burrowing• Independent growth of organs from the

body wall• Cushioning• Skeletal function• Circulation of nutrients and wastes

EucoelomateBody Designcompare HickmanFig. 9.12 and 9.13

Coelom: fluid-filled cavity between gut and body wall that is lined with mesodermal cells (peritoneum).

acoelomate

pseudocoelomate

eucoelomateendodermmesodermectoderm

(muscles, not peritoneum)

peritoneum

Most animals have a body cavity• Solid, no body cavity

except for gastro vascular cavity flatworms, cnidaria

• Pseudocoelomate- internal space in contact with digestive tract, roundworms

• True coelom - internal space lined by tissue - all other animals

Metamerism/Segmentation

Hickman Fig 9.14

Metamerism/Segmentation• Serial repetition of similar

body segments• Each segment is called a

metamere or somite• True metamerism is found in

Annelida, Arthropoda, Chordata

Metameres in Polychaeta

metamere = segment, or repeating body unit

Arthropod Tagmata

tagmata = metameres fused into functional units; singular is “tagma”

3 basic tagmata in all arthropods:• head, thorax, abdomen

– head + thorax = cephalothorax– thorax + abdomen = trunk

Segmentation and Anatomy

Metameres of an insect9 - 12 3

6

Summary

Pop quiz

• What are the 3 types of body cavity organization mentioned in chapter 9?

• List the 4 basic animal tissue types.