2Chapter 25.1 and 25.2 Objectives List the characteristics that all animals share.Differentiate between invertebrates and chordates.Describe some features of animal body plans.
3Characteristics of Animals HeterotrophicMulti-cellularEukaryoticNo cell wallsHeterotrophic – obtain nutrients and energy by eating other organismsEukaryotic – cells have a nucleus and membrane-bound organelles
4Types of Animals Invertebrates – 95% of animals Lack a backbone Examples:JellyfishSeastarWormInsect
5Types of Animals Chordates – 5% of animals Characteristics: Dorsal, hollow nerve chordNotochordLong supporting rod running length of bodyTail extending past anusPharyngeal pouchesPaired structures in throat regionMost are vertebrates (animals with backbones)Examples: fish, amphibians, reptiles, birds, mammalsAll chordates exhibit four characteristics at some point in their lives:1. hollow nerve cord that runs along the dorsal (back) part of the body; nerves branch from this nerve cord2. notochord – long supporting rod that runs length of body just under nerve cord; most chordates have a notochord only when they are embryos3. postanal tail – tail that extends past anus (at some point in life)4. pharyngeal pouches – paired structures in throat region (aka pharynx) – in fish, slits develop that connect the pouches to the outside of the body (may develop into gills for gas exchange)Most chordates are vertebrates (except for few odd aquatic animals known an invertebrate chordates)
6Check-in List the characteristics all animals have Multicellular, heterotrophs, eukaryotes, no cell wallsWhat characteristic do all invertebrates share?No backboneWhat characteristics do all chordates have sometime in their life cycle?Hollow nerve cord, notochord, postanal tail, pharyngeal pouches
7Levels of Organization CellsTissuesOrgansOrgan systemsOrganismNext 5 slides describe some features of animal body plans: levels of organization, body symmetry, differentiation of germ layers, formation of body cavities, and patterns of embryological development.
8Types of Body Symmetry Asymmetry – no symmetry Radial symmetry – body parts extend from central pointBilateral symmetry – two sides (mirror image)Anterior – frontPosterior – backDorsal – upperVentral - lowerThree types of symmetry that animals can have
9Differentiation of Germ Layers Cells of most animal embryos differentiate into:Endoderm – innermost layerMesoderm – middle layerEctoderm – outermost layerEndoderm – linings of digestive tract and much of respiratory systemMesoderm – muscles; much of circulatory, respiratory, and excretory systemsEctoderm – sense organs, nerves, outer layer of skin
10Formation of a Body Cavity Body cavity – fluid filled space between digestive tract and body wallAcoelomate – no body cavityPseudocoelomate – body cavity partially lined with mesodermCoelomate – body cavity lined with mesodermBody cavity provides space in which internal organs can be suspended, and room for these organs to growex. Your stomach and digestive organs are suspended in your body cavity
11Embryological Development Zygote – fertilized eggDevelops into blastula (hollow ball of cells)Blastopore – single opening to outside formed as blastula folds inwardAs zygote develops, becomes a blastula (hollow ball of cells like inflated balloon)As blastula develops, it folds in on itself (like holding balloon and pushing thumbs in toward center)Blatula becomes elongated structure with tube running in center (becomes digestive tract)Digestive tract has only one opening at first (blastopore)Efficient digestive sys needs two openings (mouth and anus)Protostome –organism in which blastopore becomes mouthDeuterostome –blastopore becomes anus
12Check-in List the levels of organization Cells Tissues Organs Organ systems OrganismsWhat type of symmetry do each of the following have?RadialBilateralAsymmetryRadial
13Check-in Identify the sides of the animal that are labeled: dorsal ventralposterioranterior
14Check-in What germ layer is the outermost layer? EctodermWhat germ layer makes up the linings of the digestive tract and respiratory system?EndodermIf an organism has a body cavity partially lined with mesoderm, what is it called?Pseudocoelomate
15Check-in What is a fertilized egg called? ZygoteOrganism in which blastopore becomes anus:DeuterostomeWhat is an organism with a body cavity partially lined with mesoderm called?Pseudocoelomate
16Chapter 26.1ObjectivesDescribe characteristics of invertebrate phyla.
17Cladogram of Nonchordate Invertebrates Cladogram – shows evolutionary relationships between organismsNodes (red circles) – show where important traits evolved in the course of evolution
18Phylum Porifera “Pore-bearer” Ex. Sponges No tissues or organ systems AsymmetricalFilter feedersSimplest animals
19Phylum Cnidaria “Nettle” or “Stinger” Ex. Hydras, Jellyfish, Sea anemones, CoralsCells organized into tissuesRadial symmetryFeed by stinging prey with nematocysts, mouth gastrovascular cavityAquatic, soft bodied, carnivorous, radial symmetrical animals with stinging tentacles arranged in circles around their mouthsSimplest animals to have body symmetry and cells organized into tissues
20Phylum Arthropoda Arthropods- “Jointed foot” Ex. Insects, crustaceans, spidersSegmented body, exoskeleton of chitin, jointed appendagesSegmented body – head and thorax or head/thorax/abdomenExoskeleton that is shed as they grow (molting)A million species have been identified – more than 3x the number of all other animal species combined!
21Nematoda - Roundworms Ex. pinworms Bilateral symmetry Tissue layers PseudocoelomateDigestive system with mouth and anusMolt (shed skin) as they growSimplest organisms to have one-way gut (mouth and anus)Because they molt – they are considered to be more closely related to arthropods than other worms
22Platyhelminthes - Flatworms Ex. planarians, flukes, tapewormsBilateral symmetryThree tissue layersAcoelomateSoft, unsegmented, flattened worms that have tissues and internal organ systemsSimplest animals to have three germ layers, bilateral symmetry, and heads
24Annelida Systems Digestion- mouth and anus, pharynx Circulation- closed system (blood contained in vessels)Respiration- some gills, skinExcretion- Nephridia, anusNervous- brain and nerve cordsReproduction-Sexual: (most), separate sexes, hermaphrodites
25Phylum Mollusca Mollusks Ex. Gastropods (snails), Bivalves (clams), Cephalopods (squid)Internal or external shellBilateral symmetryTissue layersCoelomateSoft-bodied animals with internal or external shellsComplex organ systems
26Phylum Echinodermata Echinoderms- “Spiny skin” Ex. Sea Stars, Sea Urchins, Sand DollarsInternal skeletonWater vascular system (tube feet)Radial symmetrySkin is stretched over an internal skeleton of calcium carbonate platesWater-vascular system – network of water-filled tubes that include suction-cuplike structures called tube feet (used for walking and gripping prey)Most adult echinoderms exhibit five part radial symmetryDeuterostomes – makes them more closely related to chordates than to other invertebrates (even though they have radial symmetry)
27Chapter 26.2ObjectivesDescribe characteristics of chordate phyla.
28Cladogram of Chordates Evolutionary relationships of chordatesCircles represent evolution of some important chordate adaptations
29Nonvertebrate Chordates Two invertebrateUrochordata: tunicatessubphyla:Cephalochordata: lanceletsAdult tunicates look like sponges and are filter feedersno body symmetrymost display chordate features and bilateral symmetry only during larval stagesLancelets are fishlike animals with bilateral symmetry that live in salt water.
30Jawless Fishes No true jaws or teeth Lack vertebrae Skeleton made of cartilageEx. Lampreys, hagfishDo have part of skull (why they are considered vertebrates)Have notochord as an adultLampreys – top picturefilter feeders as larvae; parasites as adultsadults typically attach themselves to fish, scrap away skin with rasping tongue, and then such host’s tissues and body fluidscalled the “vampires of the sea”Hagfishpinkish grey wormlike bodysecrete lots of slimecan tie their bodies into knotsno image forming eyes – just light detecting sensors on their bodiesfeed on dead or dying animals using rasping tongue
31Cartilaginous Fish Skeleton made of cartilage Paired fins Most have tooth-like scalesEx. Sharks, rays, skatesPaired fins allowed for greater control of body movementTail fins and powerful muscles gave greater thrustToothlike scales cover their bodies
32Bony Fish Skeleton of true bone Paired fins, scales, gills Swim bladderEx. Perch, bass, flounder
33Amphibians Means “double life” Undergo metamorphosis Young: live in water and breathe with gillsAdult: live on land and breathe with lungs and skinUndergo metamorphosisDramatic change in body formMoist skin with mucous glandsLack scales and clawsEx. Frogs, toads, newts, salamanders
34Amphibian Systems Digestive/Excretory: Nervous: Circulatory: Developed: stomach, intestines, etc.Nervous:Developed: large eyesgreat sightCirculatory:Closed circulatory systemThree chamber heartReproductive:Most lay eggs without shells in waterExternal FertilizationRespiratory:Gills when immature, lungs and skin when mature (skin must stay moist to function)
35Reptiles Vertebrates with lungs Scaly skin Leathery shelled amniotic eggsEx. Lizards, snakes, turtles, crocodiles, dinosaursDeveloped adaptations that allow them to live out of the water (do not rely on water for part of life cycle)well-developed lungsscaly skin to protect it from water lossamniotic eggs with leathery shell that allow them lay them on land (rather than in water)
36Birds Warm-blooded Feathers Strong light-weight bones Hard-shelled amniotic eggsTwo scaly legs and wings as fore-limbsEx. Hawk, eagle, penguin, ostrich, hummingbird, robinWarm-blooded reptiles (endothermic) – able to regulate own body temperature (only birds and mammals can do this – all other animals are cold-blooded (ectothermic)Descended from Archaeopteryx (dinosaur with feathers)Have strong but light-weight hollow bones to allow them to flyAlso have air sacs in addition to lungs to allow for constant air-flow (great need for oxygen when flying)
37Mammals Warm-blooded Feed young with milk from mammary glands Hair or furBreathe airFour-chamber heartMany groups of mammals-Insect-eating, Water-dwelling, Hoofed, Gnawing, etc.
38Groups of Mammals Monotremes Marsupials Placental mammals: Egg-laying mammalsEx. PlatypusMarsupialsGive birth to under-developed youngYoung develop in the pouch of the motherEx. Kangaroo, koalas, possumPlacental mammals:Give birth to young that have developed in the mother’s bodyEx. Humans, Dogs, Mice