1. Animals

2. What is an Animal? Animal – multicellular eukaryotic heterotrophs whose cells lack walls 95% of all animal species are invertebrates (no backbone or vertebral column

3. Embryology Embryology – early development Zygote undergoes series of divisions to become a blastula Blastula - Hollow ball of cells Gastrula - Blastula folds on itself, forming a single opening (blastopore) and the gastrula. –Blastopore leads into a central tube that runs the length of the developing embryo. Tube becomes the digestive tract.

4. The Fertilized Egg & Cleavage Yolk ~ nutrients stored in the egg Vegetal pole ~ side of egg with high yolk concentration Animal pole ~ side of egg with low yolk concentration Blastula ~hollow ball stage of development

5. Gastrulation Gastrula ~ 2 layered, cup-shaped embryonic stage 3 Embryonic germ layers: Ectoderm~ outer layer; epidermis; nervous system, etc. Endoderm ~ inner layer; digestive tract and associated organs; respiratory, etc. Mesoderm ~skeletal; muscular; excretory, etc. Invagination ~ gastrula buckling process to create the... –Archenteron ~ primitive gut –Blastopore ~ open end of archenteron

6. Protostomes and Deuterostomes Protosomes – an animal whose mouth is formed by the blastopore (most invertebrates) Deuterosomes – an animal whose anus is formed by the blastopore ( echinoderms and all vertebrates)

7. Animal Embryology Protostome-Deuterostome dichotomy among coelomates: protostomes (mollusks, annelids, arthropods); deuterostomes (echinoderms, chordates) a) cleavage: protostomes~ spiral and determinate; deuterotomes~ radial and indeterminate b) coelom (body cavity) formation: protostomes~ schizocoelous; deuterostomes~ enterocoelous c) blastopore fate: protostomes~ mouth from blastopore; deuterostomes~ anus from blastopore

8. Body Cavity Body cavity (coelom) formation – fluid filled space that lies between the digestive tract and the body wall. –Allow internal organs to be suspended – helpful during movement. –Provide room for internal organs to specialize and enlarge.

9. Body Symmetry Asymmetrical – no symmetry (sponge) Radial – like a bicycle wheel, no matter how you divide the animal with imaginary planes you get two equal halves (jellyfish) Bilateral – a single imaginary plane can split the animal in half (crayfish, human) –Cephalization – animals with bilateral symmetry have concentrated sense organs and nerve cells at the front end of the body (head)

11. Binomial Nomenclature The Linnaeus System works by placing each organism into a layered hierarchy of groups. Each group at a given layer is composed of a set of groups from the layer directly below. Simply knowing the two-part scientific name makes it possible to determine the other six layers.

12. Linnaeus System The groupings (taxa) of taxonomy from most general to most specific are: Kingdom Phylum (animals) or Division (plants) Class Order Family Genus Species

14. Fig. 23-1, p. 485 DOMAIN Eukarya KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Carnivora FAMILY Felidae GENUS Felis SPECIES Felis catus

15. Domain Comparison BacteriaArchaeaEukarya Prokaryote Eukaryote Unique bacterial rRNA nucleotide sequence Unique archaean rRNA nucleotide sequence Cell walls with peptidoglycan Cell walls with NO peptidoglycan Cell walls in plants and fungi “extremophiles” Cell walls resistant to osmotic shock

16. Modern Evolutionary Classification If you lived in the time of Linnaeus, how would you have classified dolphins? Barnacles and crabs? Phylogeny – study of evolutionary relationships o Species in a genus have a common ancestor o Genuses in a family have a common ancestor, etc. o Conclusion: the higher the taxon, the further back the common ancestor

17. Phylum: Porifera (“pore bearer”) Sponges Asymmetrical; no coelom; no organs Sessile (attached to bottom) Spongocoel (central cavity) Osculum (large opening) Choanocytes (flagellated collar cells) Hermaphroditic (produce both sperm and eggs)

19. Phylum: Cnidaria hydra, jellies, sea anemones, corals Radial symmetry; no coelom No mesoderm; gastrovascular cavity (GVC) (sac with a central digestive cavity) Hydrostatic skeleton (fluid held under pressure) Polyps and medusa forms Cnidocytes (cells used for defense and prey capture) Nematocysts (stinging capsule)

21. Phylum: Platyhelminthes flatworms, flukes, tapeworms Bilateral; no coelom Predators, scavengers, parasites Triplobastic; mesoderm but, GVC with only one opening Some cephalization Many pathogens (Schistosoma, Cestodidias)

23. Phylum: Nemotoda roundworms Very widespread group of animals (900,000 sp. ?) Cuticle (tough exoskeleton) Decomposition and nutrient cycling Complete digestive track; no circulatory system Trichinella spiralis

25. Phylum: Mollusca snails, slugs, squid, octopus, clams, oysters, chiton True coelom Soft body protected by a hard shell of calcium carbonate Foot (movement), visceral mass (internal organs); mantle (secretes shell); radula (rasp- like scraping organ) Ciliated trochophore larvae (related to Annelida?)

28. Phylum: Annelida earthworms, leeches, marine worms True body segmentation (specialization of body regions) Closed circulatory system Metanephridia: excretory tubes “Brainlike” cerebral ganglia Hermaphrodites, but cross- fertilize

29. Phylum: Arthropoda trilobites (extinct); crustaceans (crabs, lobsters, shrimps); spiders, scorpions, ticks (arachnids); insects (entomology) 2 out of every 3 organisms (most successful of all phyla) Segmentation, hard exoskeleton (cuticle)~ molting, jointed appendages; open circulatory system (hemolymph); extensive cephalization

33. Arthropoda: Insect characteristics Outnumber all other forms of life combined Malpighian tubules: outpocketings of the digestive tract (excretion) Tracheal system: branched tubes that infiltrate the body (gas exchange) Metamorphosis…... incomplete: young resemble adults, then molt into adulthood (grasshoppers) complete: larval stages (looks different than adult); larva to adult through pupal stage

34. Phylum: Echinodermata sea stars, sea urchins, sand dollars, sea lilies, sea cucumbers, sea daisies Deuterostomes Spiny skin; sessile or slow moving Often pentaradial Water vascular system by hydraulic canals (tube feet)

35. Chordates Notochord: longitudinal, flexible rod located between the digestive and the nerve cord Dorsal, hollow nerve cord; eventually develops into the brain and spinal cord Pharyngeal slits; become modified for gas exchange, jaw support, and/or hearing Muscular, postanal tail

36. Invertebrate chordates Both suspension feeders….. Subphy: Urochordata (tunicates; sea squirt); mostly sessile & marine Subphy: Cephalochordata (lancelets); marine, sand dwellers Importance: vertebrates closest relatives; in the fossil record, appear 50 million years before first vertebrate

38. Subphylum: Vertebrata Retain chordate characteristics with specializations…. Neural crest: group of embryonic cells near dorsal margins of closing neural tube Pronounced cephalization: concentration of sensory and neural equipment in the head Cranium and vertebral column Closed circulatory system with a ventral chambered heart

39. Vertebrate diversity Phy: Chordata Subphy: Vertebrata Superclass: Agnatha~ jawless vertebrates (hagfish, lampreys) Superclass: Gnathostomata~ jawed vertebrates with 2 sets of paired appendages; including tetrapods (‘4-footed’) and amniotes (shelled egg)

40. Superclass Agnatha Jawless vertebrates Most primitive, living vertebrates lamprey and hagfish Lack paired appendages; cartilaginous skeleton; notochord throughout life; rasping mouth

41. Superclass Gnathostomata, I Class: Chondrichthyes~ Sharks, skates, rays Cartilaginous fishes; well developed jaws and paired fins; continual water flow over gills (gas exchange); lateral line system (water pressure changes) Life cycles: Oviparous- eggs hatch outside mother’s body Ovoviviparous- retain fertilized eggs; nourished by egg yolk; young born live Viviparous- young develop within uterus; nourished by placenta

42. Superclass Gnathostomata, II Class: Osteichthyes Ossified (bony) endoskeleton; scales operculum(gill covering); swim bladder (buoyancy) Most numerous vertebrate Ray-fined (fins supported by long, flexible rays): bass, trout, perch, tuna, herring Lobe-finned (fins supported by body skeleton extensions): coelocanth Lungfishes (gills and lungs): Australian lungfish (aestivation)

43. Superclass Gnathostomata, III Class: Amphibia 1st tetrapods on land Frogs, toads, salamanders, caecilians Metamorphosis; lack shelled egg; moist skin for gas exchange

44. Superclass Gnathostomata, IV Class: Reptilia Lizards, snakes, turtles, and crocodilians Amniote (shelled) egg with extraembryonic membranes (gas exchange, waste storage, nutrient transfer); absence of feathers, hair, and mammary glands; ectothermic; scales with protein keratin (waterproof); lungs; ectothermic (dinosaurs endothermic?)

45. Superclass Gnathostomata, V Class: Aves Birds Flight adaptations: wings (honeycombed bone); feathers (keratin); toothless; one ovary Evolved from reptiles (amniote egg and leg scales); endothermic (4- chambered heart) Archaeopteryx (stemmed from an ancestor that gave rise to birds)

46. Superclass Gnathostomata, VI Class: Mammalia Mammary glands; hair (keratin); endothermic; 4-chambered heart; large brains; teeth differentiation Evolved from reptilian stock before birds Monotremes (egg-laying): platypus Marsupials (pouch): opossums, kangaroos, koalas Eutherian (placenta): all other mammals