Invertebrate Classification & Relationships1

Marine Invertebrate Zoology

Invertebrate Classification and Relationships

The Meek Will Inherit the Earth

Invertebrate Classification & Relationships3

Why Study Invertebrates?

Many diseases that effect humans and the animals we depend on are caused by invertebrates

Invertebrates are the base of most food webs

Invertebrates are the base of many medical studies:

– Control of gene expression

– Aging, cell death, fertilization and chemoreception

– Transmission of nerve impulses, biochemical basis of learning and memory

– Genetic basis for the predisposition for major diseases (i.e. type II diabetes)

– Isolating unique chemicals for biomedical reasons

– Using invertebrates as indicators in monitoring aquatic systems for pollutants

Invertebrate Classification & Relationships5

Invertebrate Classification and Relationships

Classification by cell #, and body symmetry Classification by developmental pattern Classification by evolutionary relationship

– Methods used in deducing evolutionary relationships

Classification by habitat and lifestyle

Invertebrate Classification & Relationships6

Classification by Cell #, and Body Symmetry

Cell Number– Metazoans – Unicellular

Body Symmetry

Bilateral

Radial

Asymmetrical

Invertebrate Classification & Relationships7

Classification by Developmental Pattern

Multicellular animals have been divided into two groups based on the # of germ layers– Germ layer

Diploblastic– Ectoderm– Endoderm

Triploblastic – Mesoderm

Most metazoans are triploblastic

Invertebrate Classification & Relationships8

Classification by Developmental Pattern

Triploblastic animals can be classified even further

AcoelomatePseudocoelomate

Coelomate

Invertebrate Classification & Relationships9

Different Developmental Types

Triploblastic

Acoelomate Pseudocoelomate Coelomates

Protostomes Deutrostomes

Invertebrate Classification & Relationships10

Advantages of the Coelom

The digestive system is independent of the body wall and locomotory activities

Room for the gut, gonads, and embryo’s to bulge

Fluid in coelom can distribute oxygen, nutrients and hormones through the body

Fluid filled coelom leads to more effective locomotory systems

Invertebrate Classification & Relationships11

Classification by Evolutionary Relationship

By far the most familiar is the frame work created 250 years ago by Linnaeus

Organisms grouped in a taxon show a high degree of similarity

Kingdom Family

Phylum Genus

Class Species

Order

Binomial nomenclature

Invertebrate Classification & Relationships12

Deducing Evolutionary Relationships

How do we compile evolutionary relationships?– PCR (polymerase chain reaction)

In what ways are evolutionary relationships depicted?– Cladograms

Invertebrate Classification & Relationships14

Classification by Habitat and Lifestyle

Terrestrial, marine, or aquatic Intertidal or subtidal Mobile, sessile, or sedentary, planktonic Herbivores, carnivores, suspension feeders, deposit

feeders, filter feeders Symbiotic associations

– Ectosymbionts – Endosymbionts– Mutualism, commensalism, parasitism

Invertebrate Classification & Relationships15

Classification

The 5 Kingdoms we use today.– Monera: single celled, prokaryote organisms

Cyanobacteria (blue-green algae)

– Protista: single celled, contains nucleus and internal subdivisions

Diatoms, dinoflagellates, and protozoans

– Fungi: multicellular, no photosynthesis, nutrition by absorption

Mushrooms

– Plantae: multicellular, autotrophs– Animalia: multicellular, heterotrophs

Multiple Kingdom and Domain Classification