Presentation on theme: "Introduction to Animals"— Presentation transcript:
1 Introduction to Animals Bio II Chapter 32Introduction to Animals
2 Animals that have a backbone Animals that do not have a backbone Animals: multicellular, heterotrophic (eat for energy) organisms that lack a cell wall.VertebrateinvertebrateAnimals that have a backboneAnimals that do not have a backboneAccount for more than 95% of all animal species
3 Characteristics of animals Multicellular OrganizationHeterotrophySexual Reproduction and DevelopmentMovement
4 1. Multicellular Organization all bodies are multicellularSome have larger # than others, 50 – 100 trillion cellsCells do not lead independent livesEach cell depends upon the presence and functioning of other cellsCauses a “division of labor” among cells: each has a job
5 SPECIALIZATION: adaptation of a cell for a particular function Each cell has a “job” to do, from digesting food, to removing waste, to reproduction.Cell: smallest unit that can perform life processes
6 Specialization Heirarchy cellsTissue: group of cells that perform a particular functionOrgan: group of tissues that perform a particular functionSystem: group of organs that perform a particular function
7 2. HeterotrophyHeterotrophy: to obtain complex organic molecules from other sourcesAnimals accomplish this through INGESTIONINGESTION: take in organic material or food
8 3. Sexual Reproduction & Development AsexualSexual
9 SEXUAL REPRODUCTION: 2 haploid gametes merge zygote Zygote: diploid cell that results from the fusion of the gametesThe zygote undergoes mitotic cell division (Development)The big mass of cells undergoes DIFFERENTIATION: cells become specialized and therefore differentiate from each other.
10 MOVEMENT comes from their interrelationship Nervous tissueMuscletissueMOVEMENT comes from their interrelationship
11 ORIGIN & CLASSIFICATION Taxonomy: the science of describing, naming, and classifying organismsScientists use a “phylogenic diagram” page 653 to relate similar organisms
14 The 1st Animals Probably arose from the sea Evolved from protists First to be multicellularHad flagellaSee chart on page This phylogenic diagram is a HYPOTHESIS for the relationship in the animal kingdom .Far right: Chordata
15 ChordatesChordate: animals with a notochord (a firm, flexible rod of tissue located in the dorsal part of the body.At some stage of development, all chordates have:Notochord:Dorsal Nerve Cord: a hollow tube above the notochordPharyngeal pouches: small “outpockets” of the anterior digestive tract.
16 Body Structure of Invertebrates Those that lack true tissues and an organized body shapeThose that have very organized tissues and a consistent body shape
17 4 elements of body structure Patterns of SymmetryGerm LayersBody CavitiesBody Structure & Relatedness
18 1. Patterns of Symmetry p655Symmetry: body arrangement in which parts that lie on opposite sides of an axis are identicalAsymmetricalRadialBilateral
19 Asymmetrical Asymmetry: do not display any symmetry Animals have the simplest body plan of allExample: sponges
20 Radial SymmetryRadial Symmetry: a body plan in which the parts are organized in a circle around an axisAnimals that have a top and bottom sideThey do not have a front, back, right or left end.Example: cnidarians (sea anemone) page 655
21 Bilateral SymmetryBilateral Symmetry: having similar halves on either side of a central planeCephalization: concentration of brain structures in anterior of animal Example: squirrelDorsal( back side)Ventral( abdomen side)Anterior(toward the head)Posterior(toward the tail)
22 2. Germ LayersTissue layers in the embryos of all animals except sponges. (Sponges have no true tissue.)Can be 2 or 3 layers, depending upon the organisms.Every organ and tissue arises from a germ layer.
23 3. Body CavitiesBody-cavity: a fluid-filled space that forms between the digestive tract and the outer wall of the body during developmentNot all invertebrates have a body cavityAid in movement by providing a firm, fluid structure against whichmuscles can contractAllows for movement of the external body, compared to the internal bodyActs as a reservoir and medium of transport for nutrients and wastes
24 4. Body Structure & Relatedness Similarity in body plans allows forclassificationPredicting the pastrelationships
25 Invertebrate 7 main characteristics Symmetry Support of the body SegmentationSupport of the bodyRespiratory & Circulatory systemsDigestive & Excretory systemsNervous systemReproduction & Development
26 1. Invertebrate Symmetry Radial SymmetryBilateral SymmetryExample: jellyfishAllows animal to receive stimuli from all directionsAllows for cephalizationMost invertebrates have this type of symmetryExamples range from slugs to squids
27 2. Invertebrate Segmentation Segmentation: body composed of a series of repeating similar unitsSimplest form seen in earthwormMore complex form seen in crayfish; fusion of segments to create a head and chest region
28 3. Invertebrate Support of the Body Very diverse means of support“natural sponge” in stores: that is the dried skeletonRoundworms: pressure of fluid-filled body cavityEXOSKELETON:rigid outer covering that protects the soft tissues of many animalsLimits the size of the animalMay impede the movementDoes not grow; must be shed as animal growsExamples: crayfish
29 4. Invertebrate Respiratory & Circulatory Systems Produce CO2: therefore must have gas exchangeGas exchange: occurs best in moist environmentSome invertebrates: it occurs across the body covering. Others: have GILLS: organs that consist of blood vessels that exchange gas in water2 types of circulatory systems:OPEN: fluid pumped thru vessels and into body cavity and back to heartEx.: some mollusks & arthrodpodsCLOSED: Heart pumps blood thru vessels and into a simple loop back to the heartEx.: annelids
30 5. Invertebrate Digestive & Excretory Systems Simpler animals: occurs within individual cellsMore complex animals: has a digestive tract (gut) in which nutrients are absorbedSimpler animals: waste is excreted as NH3 (ammonia)More complex animals: NH3 is filtered and converted to less toxic substances; water is reabsorbed by body
31 6. Invertebrate Nervous System Sponges (simpler animals)Mollusks (more complex)Have no neurons to loosely connected neuronsVery diverse systemCan contract body in response to stimuliVery complex animals can exhibit decision-making behavior (like the octopus)
32 7. Invertebrate Reproduction & Development Both sexual & asexualSome are “hermaphrodites”: both sexesex. EarthwormProduces both male & female gametesIndirect development: has an intermediate stage called a larva stage.Larva: immature, free-living form of adultDirect development: young animal born with same appearance and way of life it will have as an adultNo larva stage
33 Larva has an intermediate larval stage. ZygoteYoung LarvaOlder LarvaPupaAdultIndirect DevelopmentExample:Beetle DevelopmentLarva has an intermediate larval stage.Larva is an immature for that exhibits physical traits that are different from those of the adult.
34 VERTEBRATE CHARACTERISTICS pg 659 Have a backboneIncludes fishes, amphibians, reptiles, birds & mammalsAll except fishes spend part or all of their life on landIn order to adapt to life on land:Support of the bodyConservation of water
35 1. Vertebrate Segmentation & Support of the Body Yes, they are segmented! Ex. Ribs & vertebraeAs terrestrial vertebrate evolved from aquatic vertebrates, their limbs and muscles evolved to give greater support & mobility.Humans: BIPEDALHead is positioned directly over the body
36 2. Vertebrate Body Coverings INTEGUMENT: outer coveringFish and amphibians adapted to moist environmentsTerrestrial adapted to dry conditionsAll bodies are made of water-filled cells. Outer covering is watertight!In some vertebrates such as amphibians, skin serves as a respiratory organ.In some vertebrates such as reptile, skin serves as protection.In some vertebrates such as birds, feathers serve as insulation.
37 3. Vertebrate Respiratory & Circulatory Systems Aquatic Vertebrates: gases exchange in gillsTerrestrial Vertebrates: LUNGS: organs for gas exchangeCLOSED circ. System with a MULTICHAMBERED HEARTSeparates oxygenated and deoxygenated bloodImproves efficiency
38 4. Vertebrate Digestive & Excretory Systems Digestion occurs in the GUT: runs from mouth to anusIn vertberates, the gut is long and folded to increase surface area for nutrient absorptionHuman tract: 23 feet longProduce toxic ammonia (NH3)Must expel waste w/o losing water!Kidneys filter the waste in the blood while regulating water levels in the body
39 5. Vertebrate Nervous System Highly organized brainsFish: mainly used to process sensory information.Limited amount is used to decision makingDogs and such display complex and flexible behavior. Much of brain is given to decision making.Brain is large in respect to body size.
40 6. Reproduction & Development Fish & amphibians: eggs & sperm are released directly into the water where fertilization takes placeReptiles, birds & mammals: egg & sperm unite in female bodyZygote nourished by egg yolk until hatch.Most of development occurs OUTSIDE of female’s body.Amphibians & fish: indirect developmentAll others: direct dev.