Month Day Lecture

Oct 13 Fungi

16 The coral reef

18 Animals—worms

20 Animals—bugs to primates

23 Human evolution

25 Biodiversity revisited

27 Exam review

30 Exam

Trichoplax adhaerens

Animals...

• Monophyletic

Animals...

• Monophyletic

• Multicellular Eukaryotes

Animals...

• Monophyletic

• Multicellular Eukaryotes

• High cellular differentiation

Animals...

• Monophyletic

• Multicellular Eukaryotes

• High cellular differentiation

• Chemoheterotrophs

Animals...

• Monophyletic

• Multicellular Eukaryotes

• High cellular differentiation

• Chemoheterotrophs

• Feed by ingestion and digestion

Animals...

• Monophyletic

• Multicellular Eukaryotes

• High cellular differentiation

• Chemoheterotrophs

• Feed by ingestion and digestion

• Exhibit complex behavior

Chordates

Echinoderms

Arthropods

Annelids

Mollusks

Rotifers

Roundworms

Flatworms

Cnidarians

SpongesMulticelled Ancestry

Radial Ancestry

Bilateral Ancestry

Coelomate Ancestry

Single-celled, protistanlike ancestors

Phylum Porifera: sponges

Phylum Cnidaria: jellyfish, corals, sea anemones

Phylum Ctenophora: comb jellies

These animals are...

Radial and biradially symmetrical

Most other animals are bilaterally symmetrical

Radial symmetry

posterior

anterior

Bilateral symmetry

dorsal

ventral

Chordates

Echinoderms

Arthropods

Annelids

Mollusks

Rotifers

Roundworms

Flatworms

Cnidarians

SpongesMulticelled Ancestry

Radial Ancestry

Bilateral Ancestry

Coelomate Ancestry

Single-celled, protistanlike ancestors

Bilateral symmetry and cephalization

Phylum Platyhelminthes: flatworms

 Life cycle of Schistosoma japonicum

Phylum Platyhelminthes: flatworms

Phylum Nematoda: roundworms

These animals are...

Acoelomate: no enclosure around the gut

Most other animals are coelomate: enclosure around gut

epidermis gut cavity

no body cavity; region between gut and body wall packed with organs

Acoelomate organism(flatworm)

epidermis gut cavity

peritoneumlined body cavity (coelom); lining also holds internal organs in place

Coelomate organism(human)

Chordates

Echinoderms

Arthropods

Annelids

Mollusks

Rotifers

Roundworms

Flatworms

Cnidarians

SpongesMulticelled Ancestry

Radial Ancestry

Bilateral Ancestry

Coelomate Ancestry

Single-celled, protistanlike ancestors

Phylum Nemertea: the Spiralians

Phylum Annelida: the segmented worms

Phylum Mollusca: the mollusks

Chordates

Echinoderms

Arthropods

Annelids

Mollusks

Rotifers

Roundworms

Flatworms

Cnidarians

SpongesMulticelled Ancestry

Radial Ancestry

Bilateral Ancestry

Coelomate Ancestry

Single-celled, protistanlike ancestors

And relatives

The “Ecdysozoans”

The “Ecdysozoans”—moulting animals

• Exoskeleton– flexible but tough laminate– Protects from damage, water loss

• Segmented joints for movement

Exoskeletons

The “Ecdysozoans”—molting animals

• Exoskeleton– flexible but tough laminate– Protects from damage, water loss

• Segmented joints for movement

• Molting allows growth

adultyoungegg

Growth andmolting

adultnymphsegg

Incompletemetamorphosis

adultlarvaeegg

Completemetamorphosis

Worm-like ecdysozoans

Onychophorans

Tardigrades (waterbears)

Arthropod: “Jointed foot”

• Dominant species on earth– 1.5 million species– 1018 individuals

Arthropod: “Jointed foot”

• Dominant species on earth– 1.5 million species– 1018 individuals

• Spiders and their relatives– Aquatic and terrestrial

Arthropod: “Jointed foot”

• Dominant species on earth– 1.5 million species– 1018 individuals

• Spiders and their relatives– Aquatic and terrestrial

• Crustaceans– Aquatic

Arthropod: “Jointed foot”

• Dominant species on earth– 1.5 million species– 1018 individuals

• Spiders and their relatives– Aquatic and terrestrial

• Crustaceans– Aquatic

• Uniramia: the insects– Terrestrial

Vertebrates

Crustaceans

Insects

Mollusks

Roundworms

Plants

Fungi

Protozoans

0 400 800 1,200 1,600

Number of species (x 1,000)

over 4 million

Red = Known speciesGold = Estimated number of species not yet discovered

 Current species diversity

Characteristics of arthropods

• Rigid exoskeleton with chitin

• Jointed appendages moved by muscles

Spider relatives

Arachnids-the true spiders

Crustaceans

Myriapod: “countless feet”

Insects: group 1

Insects: group 2

Insects: group 3