the endosymbiotic theory reduced carbon compounds + o 2 high atp yield electron transport reduced...

THE ENDOSYMBIOTIC THEORY

Reduced carboncompounds + O2

High ATPyield

Electron transport

Reduced carboncompounds

Low ATPyield

Fermentation

Aerobic bacterium

Anaerobic eukaryote

chain

Pyruvateand O2

ATP

1. Eukaryotic cell surroundsand engulfs bacterium.

2. Bacterium lives withineukaryote cell.

3. Eukaryote supplies bacteriumwith reduced carbon compounds.Bacterium supplies eukaryote withATP.

Figure 27.12

The first animals (metazoans)

• They did not appear until about 600 million years ago

• But they rapidly radiated - the Cambrian explosion

Hallucigenia

Opabinia - Burgess Shale

Opabinia - Burgess Shale

Wiwaxia - Burgess Shale

Wiwaxia - Burgess Shale

Yohoia - Burgess Shale

Marrella - Burgess Shale

Marrella - Burgess Shale

Anomalocaris - Burgess Shale

Choanoflagellata

Porifera - sponges

Collar cell of a sponge

Cnidaria - anemones

Cnidaria - jellyfish

Cnidaria - corals

Ctenophora - comb-jellies

Brachiopoda - lamp shells

Echinodermata

Hemichordata - acorn worms

Chordata - sea squirts, lancelets,

vertebrates

Platyhelminthes - flatworms

Nemertea - ribbon worms

Mollusca

Annelida - segmented worms

Annelida - earthworm

Annelida - polychaetes

Arthropoda - arachnids

Arthropoda - crustaceans

Arthropoda - insects

Arthropoda - centipedes and millipedes (myriapods)

Onychophora - velvet worms

Nematoda - roundworms