First Animals Soft bodies so Soft bodies so trace fossils only trace fossils only Sponges Sponges Jelly fish Jelly fish Worms Worms Late Proterozoic Late Proterozoic

Time Line of Animal Evolution 1 st Fossil evidence of animals 570 mya = Proterozoic Eon 1 st Fossil evidence of animals 570 mya = Proterozoic Eon Massive adaptive radiation of animals called the Cambrian Explosion signaled the start of the Phanerozoic Eon Massive adaptive radiation of animals called the Cambrian Explosion signaled the start of the Phanerozoic Eon Cambrian Explosion due to Cambrian Explosion due to increased oxygen for aerobic respiration increased oxygen for aerobic respiration more energy = larger more mobile animals more energy = larger more mobile animals move into new areas and adapt move into new areas and adapt

Phanerozoic begins with Cambrian Explosion

Evolution of Animals Some type of Protist mutated to become multicellular Some type of Protist mutated to become multicellular Multicellular organisms start as a single cell (zygote) and grow into organisms with groups of specialized cells performing different functions Multicellular organisms start as a single cell (zygote) and grow into organisms with groups of specialized cells performing different functions All animals are multicellular All animals are multicellular

Proterospongia = Protist & common ancestor to all animals?

Proterospongia: Colonial, Unicellular Protists

Sponge collar cells

Phylum Porifera Sponges Sponges Only 3 types of cells Only 3 types of cells Collar cells Collar cells Amoebocytes Amoebocytes Epidermis cells Epidermis cells (protective outer layer of cells) (protective outer layer of cells) No tissues No tissues Cells held together by jelly like substance Cells held together by jelly like substance Skeleton make of proteins Skeleton make of proteins Asymetrical Asymetrical

Origin of sponges

Sponges are sessile filterfeaders feeding-made-visible feeding-made-visible feeding-made-visible feeding-made-visible animation-wild-ride-through-sponge animation-wild-ride-through-sponge animation-wild-ride-through-sponge animation-wild-ride-through-sponge

Intracellular digestion (like protists) Collar cells take in food by endocytosis Food digested in food vacuoles Some food passed to amoebocytes Amoebocytes carry food around sponge body. (circulaton)

All other Animals have True Tissues & symmetry

Phylum Cnidaria Have stinging cells = cnidocytes Have stinging cells = cnidocytes Have tentacles Have tentacles First predators..First muscle-like cells (movement) First predators..First muscle-like cells (movement) Radial symmetry = sit and wait predator Radial symmetry = sit and wait predator 1 st nervous system = 1 st nervous system = nerve net & eye spots nerve net & eye spots

Digestion & Circulation Have gastrovascular cavity for Have gastrovascular cavity for digestion & circulation digestion & circulation 1 st extra cellular digestion 1 st extra cellular digestion – cells lining GVC secrete digestive enzymes – cells lining GVC secrete digestive enzymes Evolutionary advantage = can eat larger food Evolutionary advantage = can eat larger food Cilia push digested food around the GVC Cilia push digested food around the GVC GVC branches into all tentacles: comes near all cells GVC branches into all tentacles: comes near all cells

Prey capture vM1_Y vM1_Y vM1_Y vM1_Y

Jellyfish Reproduction Moon jellies Moon jellies u0I u0I u0I u0I Hydra eating Hydra eating N74I N74I N74I N74I

All other animals have Bilateral symmetry

Flatworms had it FIRST!! Bilateral symmetry Bilateral symmetry Directional motion = 1 st mobile predator Directional motion = 1 st mobile predator Cephalization – development of a head Cephalization – development of a head Ganglia: bundle of nerve cells make up a pre-brain Ganglia: bundle of nerve cells make up a pre-brain Nerves concentrated at ‘head end’ since sensory cells were concentrated at that end Nerves concentrated at ‘head end’ since sensory cells were concentrated at that end Sensory nerves formed bundles = ganglion Sensory nerves formed bundles = ganglion Eyespots detect light, Eyespots detect light, Auricles detect chemicals ‘smell’ Auricles detect chemicals ‘smell’ 2 nerve cords transmit info to rest of body 2 nerve cords transmit info to rest of body

Evolution of Bilateral Symmetry

Flatworm primitive Traits Central mouth and GVC Central mouth and GVC

Free-living Flatworms = Class Turbellaria Marine Marine Fresh-water

Flukes = Class Trematoda Parasites of blood and liver Parasites of blood and liver

Swimmer’s Itch =Schistosoma

Tape Worms = Class Cestoda

Human Tape Worm Sources =Under cooked Sources =Under cooked Beef (N. America) Beef (N. America) Pork(S. America) Pork(S. America) Fish (Asia) Fish (Asia) Prevention Prevention Cook your meat!!! Cook your meat!!!

Embryo Development All Animals can do Sexual Reproduction All Animals can do Sexual Reproduction All make eggs and sperm All make eggs and sperm All start out as a single celled zygote All start out as a single celled zygote ALL Zygotes grow into a hollow ball of cells called a ALL Zygotes grow into a hollow ball of cells called a blastula blastula Blastula gets indented forming a Blastula gets indented forming a gastrula gastrula

ALL Gastrulas develop at least 2 tissue layers ALL Gastrulas develop at least 2 tissue layers endoderm and ectoderm (diploblastic) endoderm and ectoderm (diploblastic) Some develop 3 layers endo, ecto and mesoderm Some develop 3 layers endo, ecto and mesoderm (triploblastic) (triploblastic)

All Animals more advanced that flatworms have a body cavity Provides room for organs to develop Body Cavities are called coeloms

Types of body cavity (coelom) Acoelomate Pseudocoelomate Coelomate Acoelomate Pseudocoelomate Coelomate

Round Worms = Phylum Nematoda 1 st Animal with a body cavity =pseudocoelom 1 st Animal with a body cavity =pseudocoelom Fake body cavity – just a space between layers. Fake body cavity – just a space between layers.