2Characteristics All multicellular & eukaryotic Cells lack cell walls and come in a variety of shapes.Ingestive heterotrophs (take in food and internally digest it).
3Characteristics cont’d Have some type of skeletal supportExoskeletons found in arthropods cover the outside of the body but limit size.Endoskeletons found in all vertebrates are found inside the body and are made of cartilage and/or bone.
4Characteristics Cont’d Worms have fluid-filled internal cavities giving them skeletal support.Sponges have the simplest skeleton.May be sessile (attached and non-moving) or motile (able to move around).
5Characteristics Cont’d Muscular tissue provides energy for movement.Reproduces sexually.Shows levels of organization including cell, tissue, organ, and system.
6Characteristics Cont’d Most show division of labor among cells.Cells are specialized for particular functions.Cell junctions hold individual cells in a tissue together. They link neighboring cells.Most vertebrates have a backbone or spine made of repeating bones called vertebrae that protect the spinal cord.Some show cephalization (have a head with sensory organs concentrated there).
7Invertebrate Groups Simplest animals Contains the greatest number of animal speciesMost found in waterDo not have a backboneIncludes sponges, cnidarians, flatworms, roundworms, annelids (segmented worms), mollusks, arthropods, and echinoderms.
8Vertebrate Groups More complex animals Most have a backbone Includes fish, amphibians, reptiles, birds, and mammals.
9Body Areas Dorsal is the back or upper surface Ventral is the belly or lower surfaceAnterior head or front endPosterior is the tail or hind end opposite the headOral surface in echinoderms is where the mouth is located (underside)Aboral surface in echinoderms is the surface opposite the mouth
13Body SymmetrySymmetry is the arrangement of body parts around a central plane or axisAsymmetry occurs when the body can’t be divided into similar sections (sponges)copyright cmassengale
14Body SymmetryRadial symmetry occurs when body parts are arranged around a central point like spokes on a wheel (echinoderms)Most animals with radial symmetry are sessile (attached) or sedentary (move very little)copyright cmassengale
16Body SymmetryBilateral symmetry occurs when animals can be divided into equal halves along a single planeOrganisms will have right and left sides that are mirror images of each otherMore complex type of symmetrycopyright cmassengale
17Body Symmetry Animals with bilateral symmetry are usually motile Animals have an anterior and posterior endsShow cephalization (concentration of sensory organs on the head or anterior end)copyright cmassengale
20SegmentationOccurs whenever animal bodies are divided into repeating units or segmentsFound in more complex animalsEarthworms show external segmentation, while humans show internal segmentation (vertebrae of the backbone)Segments may be fused together such as cephalothorax covering chest & head of a crayfish
23Tissue Development Cont’d All animals reproduce sexually, but some also reproduce asexually (sponges bud & flatworms fragment)Zygote is the fertilized egg all animals form fromZygote undergoes rapid cell divisions known as cleavage to become hollow ball of cells called blastulaBlastocoel is the central cavity of the blastula
24Tissue Development Cont’d Blastula folds inward at one point to form an opening & two cell or germ layers; process called gastrulationNew cup-shaped structure with 2 cell layers is called the gastrulaArchenteron is the deep cavity of the gastrula that forms the primitive gutBlastula
25Tissue Development Cont’d Inner germ layer called endoderm & outer germ layer called ectodermOpening may become the mouth or the anusProtostomes (mollusks, arthropods, & annelids) develop mouth from blastopore, while deuterostomes (echinoderms & vertebrates) develop an anus from blastopore
26Tissue Dev. Cont’dSome animals form a third germ layer in the middle called mesodermCells differentiation during development changing their shapes to fit their function ( neurons or nerve cells become long to conduct messages)
27Germ Layers Form tissues, organs, & systems NOT present in sponges Ectoderm (outer) – forms skin, nerves, sense organsEndoderm (inner) – forms liver and lungsMesoderm (middle) – forms muscles & other systemscopyright cmassengale
28Body Layers Sponges have NO tissues or organs, only specialized cells Cnidarians like jellyfish & coral have only two body layers & one body opening (mouth/anus) into gastrovascular cavityCnidarians have outer epidermis & inner gastrodermis with jelly-like mesoglea between the layerscopyright cmassengale
29Body LayersAll worms, mollusks, arthropods, echinoderms, and vertebrates have three cell layersEctodermEndodermMesodermcopyright cmassengale
44Support Systems Spongin & spicules (sponges) Limestone cases (corals) Exoskeletons of Chitin (arthropods)Limits sizeMust be shed or molted to growAnimal vulnerable to predators during moltingcopyright cmassengale
45Support SystemsHydrostatic skeleton – fluid filled body cavity (worms)Inner Calcium plates or Test (echinoderms)Bone and/or cartilage endoskeleton (vertebrates)copyright cmassengale
48Digestive Systems All animals are ingestive heterotrophs Choanocytes (specialized cells) capture & digest food for spongesGastrovascular cavity with one opening in cnidarians and flatworms for food to enter & leave; called two-way digestive systemcopyright cmassengale
49Gastrovascular Cavity with Mouth Only (Cnidarians)
51Digestive SystemsAnimals with a one-way digestive system have a mouth and an anusFood enters the mouth, continues in one direction through the digestive tract, and wastes leave through the anusIncludes annelids, arthropods, & vertebratescopyright cmassengale
53Circulatory Systems Transports oxygen & nutrients to cells Carries away wastes & carbon dioxide from cellsSponges, cnidarians, & flatworms do NOT have circulatory systemscopyright cmassengale
54Circulatory SystemsIn closed circulation, blood remains inside blood vessels until it reaches cells (annelids & vertebrates)In open circulation, blood is pumped out of blood vessels to bathe tissues in the body cavity or hemocoel (arthropods & mollusks)copyright cmassengale
56Respiratory System Taking in O2 & releasing CO2 Gases can diffuse across moist surfaces (earthworms)Gills filter O2 from water (aquatic animals)Lungs take O2 from air (terrestrial animals)copyright cmassengale
58Nervous System Coordinates the activities of the animal’s body Neurons – nerve cells that transmit electrochemical signalsNerve net - network of neurons, very little coordinationGanglion – clusters of neurons; may serve as a simple brainBrain – control center at anterior endcopyright cmassengale
60Excretory SystemExcretion is the removal of nitrogen wastes from the bodyDiffusion is used by simple aquatic animalsFlame cells remove wastes in flatwormscopyright cmassengale
61Excretory SystemCoiled tubules called nephridia remove nitrogen wastes in arthropodsTerrestrial animals remove wastes with KidneysMay be paired (most vertebrates)May be single as in birdscopyright cmassengale
63Reproductive SystemReproduction is the process by which organisms make more of their own kindAll animals reproduce by sexual reproduction (produce eggs and sperm)Some animals also use asexual reproduction creating identical offspringcopyright cmassengale
64Types of Animal Asexual Reproduction Regeneration or Fragmentation is the breaking off of pieces and the re- growth of a new organismFound in simple animals like Sponges and Flatwormscopyright cmassengale
65Budding occurs in hydra whenever a growth on the parent is released Creates a clonecopyright cmassengale
66Komodo dragon is an example Parthenogenesis – females produce eggs that develop unfertilized into female organismsKomodo dragon is an examplecopyright cmassengale
67Most hermaphrodites do NOT fertilize their own eggs Hermaphrodite are animals like earthworms that produce BOTH eggs and spermMost hermaphrodites do NOT fertilize their own eggsMate to exchange spermcopyright cmassengale
68FertilizationExternal – sperm and eggs are released into water where they are fertilizedInternal – sperm and egg are fertilized inside the female animal’s bodycopyright cmassengale