BIOL 201: Invertebrate Zoology

Chapter 1: Introduction to Invertebrates

Rob SwatskiAssistant Professor of Biology

HACC-York

Invertebrates

99% of all extant animal

species

1 million+

describedspecies

10-30 million undescribed

species

Approx. 34 phyla

2

3

4

Prokaryotes

No organelles

No nucleus

Bacteria & Archaea

Eukaryotes

Organelles present

Nucleus present

Protists, fungi, plants,

animals

3 Domains of Life

Bacteria Archaea Eukarya

5

Domain Bacteria

6

7

Domain Archaea

Domain Eukarya

Kingdom Protista

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia

8

Kingdom Protista

9

Kingdom Fungi

10

11

Kingdom Plantae

12

Kingdom Animalia

13

DNA

Chromosomes

Genes

14

DNA double helix Single strand of DNA15

16

1859: Charles Darwin published

The Origin of Species

Main Ideas of Evolution

Current species are descendants of

ancestral species

“Descent with modification”

Natural selection

Adaptation

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18

19

20

Evolution accounts for the unity & diversity of life

Phylum Overview

21

22

Protozoa

Animal-like protists

Not part of kingdom Animalia

Notinvertebrate

animals

Important evolutionary

link23

Phylum Porifera

sponges 24

Phylum Cnidaria

jellyfishes,corals, anemones25

Phylum Ctenophora

comb jellies 26

Phylum Platyhelminthes

flatworms

27

Phylum Nemertea

ribbon worms 28

Phylum Nematoda

roundworms 29

Phylum Mollusca

chitons, clams, snails, slugs, squid, octopi 30

Phylum Annelida

segmented worms31

Phylum Arthropoda

horseshoe crabs, arachnids, crustaceans, myriapods, insects 32

Phylum Phoronida

lopohophorates33

Phylum Brachiopoda

lamp shells34

Phylum Bryozoa

bryozoans 35

36Ernst Haeckel

Phylum Echinodermata

starfishes, brittle stars, sea urchins, sea cucumbers, sand dollars 37

38

Phylum Hemichordata

acorn worms 39

40

Phylum Hemichordata

pterobranchs

Phylum Chordata

tunicates 41

Carl Linne“You can call me

CarolusLinnaeus”

42

Taxonomy…Today

Traditional rank-based Linnaean classification still used, but limited

value

Binomial nomenclature (Genus, species) still

popular

Much more emphasis on evolutionary relationships (phylogeneticsystematics)

Change is the only constant in taxonomy

43

Cladistics

Modern method of understanding

phylogeny

Create phylogenetic

trees (cladograms)

Based on morphology or molecular data

Homology vs. Analogy

44

45

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Autoapomorphies: evolutionary novelties

47

48

Synapomorphies

49

Ground Plan

Basic set of characteristics of

each phylum

Helps our understanding of

differences & similarities between

phyla50

Example of a ground plan: 51

52

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