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Kingdom Animalia. Chapter 32 - 34. What you need to know!. The characteristics of animals. The stages of animal development How to sort the animal phyla based on symmetry, development of a body cavity, and the fate of the blastopore The traits used to divide animals into groups
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Kingdom Animalia Chapter 32 - 34
What you need to know! • The characteristics of animals. • The stages of animal development • How to sort the animal phyla based on symmetry, development of a body cavity, and the fate of the blastopore • The traits used to divide animals into groups • Examples and unique traits for each phylum discussed. • The evolution of systems for gas exchange, respiration, excretion, circulation, and nervous control • The 4 chordate characteristics • Traits which distinguish each of the following groups: Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Birds, and Mammalia • Adaptations that allowed animals to move onto land. • How the three classes of mammals differ in their reproduction
Phyla • Porifera • Cnidaria • Platyhelmithes • Nematoda • Mollusca • Annelida • Arthropoda • Echinodermata • Chordata
Classification in Animalia Metazoa: most inclusive clad; all animal phyla; multicellular, heterotroph as opposed to protozoa (first life) Eumetazoa: true tissue animals; all phyla except porifera (sponges) Bilateria: symmetry; all phyla except cnidaria and porifera Deuterostomia: blastopore = anus; only echinodermata, chordata
Porifera • Simplest animal – no true specialized tissues • No gastrula during embryogenesis, no real germlayers • No muscle, nerve cells, digestive tract • Association of different specialized cell • Pores for water flow • choanocytes (collar cells) flagellated cells that create vortex to suck in water/food • amoebocysts (food digestion, food distribution) feeding through phagocytosis • skeleton cells make spicules made from calcium carbonate
Porifera • Sessile (attached to bottom) • Spongocoel (central cavity) • Osculum (large opening) • Sexual reproduction: sequential hermaphroditism (produce both sperm and eggs at times in their lives) • Asexual reproduction: budding
Cnidaria • hydra, jellies, sea anemones, corals • Gastrulation makes cnidarians diploblastic • endo/ectoderm • no mesoderm • Endoderm formsgastrovascular cavity (GVC): sac with a central digestive cavity – one opening • Polyps and medusa • Also called “Radiata”: Radial symmetry
Cnidaria • Hydrostatic skeleton (fluid held under pressure) • Cnidocytes-cells used for defense and prey capture on tentacles • Special cnidocytes are Nematocysts: stinging capsule that when triggered release a harpoon-like stinger
Platyhelminthes • flatworms, flukes, tapeworms • Bilateral, Triploblastic • GVC with only one opening • Acoelomates w/o body cavity: solid interior • Some cephalization: eyespot and nerve cluster anterior • Predators, scavengers, parasites with multiple hosts
Nematoda • round, hook, heartworms • Bilateral, triploblastic • pseudocoelomate • Complete digestive track • Unsegmented • No circulatory system • Cuticle (tough exoskeleton) • Decomposition and nutrient cycling • freeliving or parasitic • Trichinella spiralis (tiny worm parasites)
Mollusca • (mollus-soft) snails, slugs, squid, octopus, clams, oysters, chiton • Bilateral, true coelomates: • Digestive tract • Segmentation • Circulatory system w/ simple heart (open) • Internal or external shell -calcium carbonate • Cephalopoda: developped eyes, cephalization
Special molluscs • All have: foot (movement), visceral mass (internal organs); mantle (secretes shell); radula (mouth scraping organ) • Ciliated trochophore larvae • Classes: • Gastropoda: snails (stomach footed) • Bivalves: mussels (two-shelled) • Cephalopoda: octopusses (head footed)
Annelida • segmented worms earthworms, leeches, marine worms • Bilateral, coelomate • Body segmentation • Closed circulatory system! • Metanephridia: excretory tubes • “Brainlike” cerebral ganglia • Hermaphrodites, but cross- fertilize
Arthropoda • trilobites (extinct); crustaceans (crabs, lobsters, shrimps); spiders, scorpions, ticks (arachnids); insects (entomology) • Bilateral, coelomates • segmentation • most successful of all phyla • Extensive nervous system, muscles • open circulatory system with hemolymph • digestive tract
Special features - arthropoda • hard exoskeleton (cuticle) made from chitin (fungi!, polysaccharide with some N) • Growth through molting • Metamorphosis: juvenile looks very different than adult • jointed appendages • Ventral ladder shaped nerve chord
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) • Complete metamorphosis: larva, pupa, adult
Echinodermata • sea stars, sea urchins, sand dollars, sea lilies, sea cucumbers, sea daisies • Secondary radial symmetry (fake) due to bilateral larvae • Only deuterostomes other than chordates • Spiny skin; sessile or slow moving
Echinoderm facts • Water vascular system by hydraulic canals (tube feet) • Simple Endoskeleton • Some segmentation (disk, feet…) • Short digestive tract • Some nervous system
Vertebrate Evolution and Diversity Phylum chordata
Subphyla in Chordata Subphylum: invertebrate chordate • Urochordata and chephalochrodata: invertebrate chordates Subphylum: vertebrata Class: • Agnatha –jawless fishes • Chondrichtys-cartilage fishes • Osteichtys • Amphibia • Reptilia • Aves • Mammalia
Invertebrate Chordates • Urochordata (tunicates; sea squirt); mostly sessile & marine and Cephalochordata (lancelets); marine, sand dwellers • Importance: vertebrates closest relatives; in the fossil record, appear 50 million years before first vertebrate • Intestinal tract, no circulatory system, not vertebral column, no gills
Subphylum: Vertebrata; Class Agnatha • jawless fish lampreys, hagfish • Most primitive, living vertebrates • Cephalization in cranium • closed circulatory system • Lack paired appendages; cartilaginous skeleton; notochord throughout life; rasping mouth, no jaw • Predators preying on fishes
Class: Cartilaginous Fishes • sharks, skates, rays • Cartilaginous fishes; well developed jaws and paired fins; continual water flow over gills (gas exchange); lateral line system (water pressure changes) • Closed circulatory system, gills • Life cycles: • Oviparous- eggs hatch outside mother’s body, frogs, fishes • Ovoviviparous- retain fertilized eggs; nourished by egg yolk; young born live reptiles, birds • Viviparous- young develop within uterus; nourished by placenta, mammals
Class: Bony fishes • all other fishes • vertebral column • calcified bonemost numerous • vertebrate
Class: Amphibia • salamanders, frogs, newts, toads • 1st tetrapods on land • Frogs, toads, salamanders, caecilians • Metamorphosis; lack shelled egg; moist skin for gas exchange • No amniotic egg
Class: Reptilia • Lizards, snakes, turtles, and crocodilians • Amniote (shelled) egg • Scales with protein keratin (waterproof); • Lungs • 3 chambered heart; exothermic (dinosaurs endothermic?)
Superclass Gnathostomata, V • Class: Aves: Birds • Endothermic • Amniotic eggs • 4 chambered heart • Flight adaptations: wings (hollow-boned); feathers (keratin); toothless; one ovary • Evolved from reptiles (amniote egg and leg scales) • Archaeopteryx (stemmed from an ancestor that gave rise to birds)
Class: Mammalia • Mammary glands; hair (keratin); endothermic; 4-chambered heart; large brains; teeth differentiation to accommodate herbivore, carnivore • Evolved from reptilian before birds • Monotremes (egg-laying): platypus; echidna • Marsupials (pouch): opossums, kangaroos, koalas • Eutherian (placenta): all other mammals-placental mammals
Order: Primates • Characteristics: hands & feet for grasping; large brains, short jaws, flat face; parental care and complex social behaviors • Suborder: Anthropoidea •monkeys, apes, humans opposable thumb • 45-50 million years ago • Family: Hominid australopithecines • genus: Homo • Species: habilis, erectus, sapiens • Subspecies: neanderthaliensis, sapiens
Human evolution • Misconceptions: • 1- Chimp ancestor (2 divergent branches) • 2- Step-wise series (coexistence of human species) • 3- Trait unison vs. mosaic evolution (bipedalism, upright, enlarged brain)
The first humans • Ape-human split (5-7 mya) • Australopithecus; “Lucy” (4.0 mya) • Homo habilis; “Handy Man” (2.5 mya) • Homo erectus; first to migrate (1.8 mya) • Homo sapiens neanderthaliensis (200,000 ya) • Homo sapiens sapiens (1.0 mya?) • Several species side by side • Origin Africa