V PHYLUM CHORDATA V PHYLUM CHORDATA cont Derived

V. PHYLUM CHORDATA

V. PHYLUM CHORDATA, cont Derived Characters of Chordates ØNotochord – Flexible rod located between digestive tract & nerve cord ØDorsal Hollow Nerve Cord – Eventually develops into brain and spinal cord ØPharyngeal Slits ØPost-anal Tail Recently divided into 4 groups: ØUrochordata ØCephalochordata ØMixini ØVertebrata

V. PHYLUM CHORDATA, cont Invertebrate Chordates Lack a true backbone Suspension feeders Closest vertebrate relatives; appear 50 million years prior to vertebrates Urochordata ØTunicates, sea squirts ØSessile as adults Cephalochordata ØLancelets, amphioxus ØBurrow in sand of ocean floor

V. PHYLUM CHORDATA, cont • Myxini Ø Hagfish Ø Part of group known as craniates meaning they show pronounced cephalization Ø Lack jaws, vertebrae, paired appendages Ø Scavengers Ø Used to considered part of sub-phylum Vertebrata Ø Notochord is present lifelong

VI. PHYLUM CHORDATA – Subphylum Vertebrata Notochord replaced by vertebrae Pronounced cephalization Neural crest Closed circulatory system with chambered heart

VI. PHYLUM CHORDATA - Subphylum Vertebrata Lampreys Used to be grouped in class Agnatha with hagfish Lack jaws, paired appendages Mostly freshwater ectoparasites Cartilaginous skeleton

VI. PHYLUM CHORDATA - Subphylum Vertebrata Class Chondrichthyes Cartilaginous fishes Sharks, skates, rays Well-developed jaws; paired fins Ectotherms Continual water flow over gills Lateral line system (water pressure changes) Internal Fertilization

Class Osteichthyes VI. PHYLUM CHORDATA - Subphylum Vertebrata Ossified endoskeleton Scales Operculum Swim bladder Ectotherms Two groups ØLobe-finned - Fins supported by rod-shaped bones surrounded by a thick layer of muscle; coelocanth; lungfishes ØRay-finned – Most common type; fins supported by long, bony rods arranged in a ray pattern

Class Amphibia CHORDATA - Subphylum Vertebrata VI. PHYLUM First tetrapods, land animals Frogs, toads, salamanders Metamorphosis Ectotherms External fertilization; lack shelled egg Moist skin for gas exchange 2 → 3 chambered heart

Class Reptilia VI. PHYLUM CHORDATA - Subphylum Vertebrata Lizards, snakes, turtles, and crocodilians Internal fertilization Amniotes – Eggs have shells, extraembryonic membranes which aid in gas exchange, transfer of nutrients, protection Ectotherms 3 -chambered heart in most; 4 -chambered heart in crocs Scales with keratin

“Class Aves” VI. studies PHYLUM CHORDATA - Subphylum Vertebrata Fossil show connection between reptiles and birds; birds now included in Class Reptilia Endothermic 4 -chambered Heart Have many other adaptations for flight

Class Mammalia VI. PHYLUM CHORDATA - Subphylum Vertebrata Mammary glands Hair (keratin) Endothermic 4 -chambered heart Large brains (relative to size) Teeth differentiation Diaphragm Divided into three groups ØMonotremes – Egg-layers; platypus, anteaters ØMarsupials – Embryonic development of young completed in pouch; kangaroos, koalas, opossums ØEutherians – Placental mammals; all other mammals

VII. INTRODUCTION TO ANIMAL PHYSIOLOGY • Four Types of Tissue v v

VII. INTRO TO ANIMAL PHYSIOLOGY, cont • Epithelial Tissue § Covers body and lines organs and cavities § Forms glands § May secrete mucus, be ciliated § Held together by tight junctions § Basement membrane o Anchors one side of epithelium to tissues beneath o Extracellular matrix made up of protein, polysaccharides § Classified according to the number of layers of cells and the shape of the cells

VII. INTRO TO ANIMAL PHYSIOLOGY, cont • Connective Tissue § Bind and support other tissues § Consists of cells loosely organized in an extracellular matrix § Matrix is produced and secreted by cells

VII. INTRO TO ANIMAL PHYSIOLOGY, cont • Nerve Tissue § Senses stimuli and transmits signals from 1 part of the animal to another § Two main types of cells v Neuron v Glia

VII. INTRO TO ANIMAL PHYSIOLOGY, cont • Muscle Tissue § Capable of contracting when stimulated by nerve impulses § Fibers § 3 Types of Muscle Tissue Ø Skeletal Ø Cardiac Ø Smooth

VII. INTRO TO ANIMAL PHYSIOLOGY, cont

VIII. PHYSIOLOGICAL REGULATION • Fluid that surrounds cells is known as interstitial fluid • Temperature, water concentration, salt concentration, p. H must be kept relatively constant to maintain homeostasis • Maintained through Ø Negative Feedback Ø Positive Feedback

VIII. PHYSIOLOGICAL REGULATION, cont

VIII. PHYSIOLOGICAL REGULATION Thermoregulation • Ectothermic Ø Determined by environment • Endothermic Ø High metabolic rate generates high body heat • Physical processes Ø Metabolism § Sum of all energy-requiring biochemical reactions § Energy measured in Joules, calories, or kilocalories (Calories) § Metabolic rate may be determined by v Monitoring rate of heat loss v Measuring amount of O 2 consumed or CO 2

VIII. PHYSIOLOGICAL REGULATION Thermoregulation, cont

VIII. PHYSIOLOGICAL REGULATION Thermoregulation, cont • Physical Processes, cont Ø Conduction § Transfer of heat between objects in direct contact Ø Convection § Transfer of heat by movement of air/liquid past a surface Ø Radiation § Transfer of heat between objects not in direct contact Ø Evaporation § Loss of heat in conversion of liquid to gas

VIII. PHYSIOLOGICAL REGULATION Thermoregulation, cont. • Adaptations Ø Torpor - Low activity; decrease in metabolic rate § Hibernation § Estivation Ø Brown Fat Ø Insulation Ø Behavioral Responses

VIII. PHYSIOLOGICAL REGULATION Thermoregulation, cont. • Adaptations, cont Ø Countercurrent Heat Exchangers

VIII. PHYSIOLOGICAL REGULATION Thermoregulation, cont. • Human Thermoregulation

VIII. PHYSIOLOGICAL REGULATION Osmoregulation • Management of the body’s water content and solute composition • Animals may be classified as: v. Osmoconformer: Marine invertebrates. Solute concentration in sea equal to that of organism; therefore, no active adjustment of internal osmolarity (marine animals); isoosmotic to environment v. Osmoregulator: Include marine vertebrates, freshwater animals, land animals. Body fluids have solute concentration different from environment. Must expend energy to regulate water loss or gain.

VIII. PHYSIOLOGICAL REGULATION Osmoregulation, cont • Freshwater fishes Ø Higher solute concentration in fish → fish gains water, loses salt → doesn’t drink water, excretes large amounts of dilute urine • Marine fishes Ø Lower solute concentration in fish → fish loses water, gains salt → drinks large amount of saltwater, pumps

IX. ANIMAL REPRODUCTION

IX. ANIMAL REPRODUCTION Asexual vs Sexual Reproduction

IX. ANIMAL REPRODUCTION • Asexual § Budding § Regeneration Ø Fragmentation Ø Fission

IX. ANIMAL REPRODUCTION Mechanisms of Reproduction • Parthenogenesi s Ø Unfertilized egg development Ø Typically haploid, sterile adults Ø Daphnia, Rotifers, honeybees

IX. ANIMAL REPRODUCTION Mechanisms of Reproduction, cont Hermaphroditism ØBoth male & female reproductive systems ØOccurs in earthworms, other sessile & burrowing organisms

IX. ANIMAL REPRODUCTION Mechanisms of Reproduction, cont Sequential hermaphroditism ØReversal of gender during lifetime ØProtogynous female first ØProtandrous – male first

IX. ANIMAL REPRODUCTION Sexual Reproduction • Pheromes Ø Chemical signals released by organism Ø Influences behavior, physiology of organisms of same species Ø Active in minute amounts • Fertilization Ø External Ø Internal

X. HUMAN REPRODUCTION

X. HUMAN REPRODUCTION Gamete Production

X. HUMAN REPRODUCTION Fertilization Ø Head of sperm contains a vesicle known as the acrosome; contains enzymes that help sperm penetrate egg Ø Acrosomal reaction – hydrolytic enzymes act on egg jelly coat Ø Surface proteins on sperm bind with receptor molecules on egg Ø Sperm cell membrane fuses with egg cell membrane Ø Cell membrane of egg depolarizes, becomes impenetrable to sperm to prevent multiple fertilization (polyspermy) Ø Triggers increase in metabolic activity in fertilized egg (including completion of meiosis II)

X. HUMAN REPRODUCTION Embryonic Development

X. HUMAN REPRODUCTION Fetal Development