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Vertebrates. Biology 11. Relate the complexity of the form and function of vertebrates to the evolutionary continuum of animals. Their unifying characteristics Compare members of two or more classes
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Vertebrates Biology 11
Relate the complexity of the form and function of vertebrates to the evolutionary continuum of animals. • Their unifying characteristics • Compare members of two or more classes • Compare the vertebrates and invertebrates in terms of increasing complexity with reference to: • Endoskeleton vs exoskeleton • Presence or absence of vertebral column • Closed vs open circulatory system • Describe the diverse ecological role of vertebrates
Phylum Chordata • 3 subphyla: • Urochordata (Tunicates) • Cephalochordata (Lancelets) • Vertebrata
3 Main characteristics • Notochord- develops into vertebrate backbone • Found in embryo of most vertebrates • Supports and protects the nerve cord • Dorsal Hollow Nerve Cord- develops into vertebrate brain and spinal cord
Pharyngeal slits/pouches • Most chordates only have during embryonic stages • Become gill slits in aquatic vertebrates and becomes jaw, inner ear, and tonsils in terrestrial vertebrates
Postanal Tail • Lost during embryonic development in many vertebrates
Characteristics of Chordates • Bilateral symmetry • Coelomates • Segmentation
Vertebrae- segmented and flexible to protect nerve cord • Endoskeleton- cartilage and/or bone which grows with animal, protects internal organs, allows muscle attachment for movement • Cephalization- brain with specialized sense organs enclosed in skull for protection • Closed circulatory system- heart with 2- chambers, blood contained in arteries, capillaries, and veins
Respiratory System- blood contains hemoglobin to pick up oxygen and carbon dioxide • Reproductive system- separate sexes, mainly sexual reproduction with internal or external fertilization • Excretory System- kidneys remove metabolic wastes and reabsorb H20
Body Temperature • Birds and mammals are endothermic (warm-blooded) • Can regulate body temperature regardless of external environment. • Rest of the vertebrates are ectothermic (cold-blooded). • Their body temperature varies with changes in external environment.
Subphylum Vertebrata: Classification • Class Agnatha – lampreys • Class Chondrichthyes – sharks • Class Osteichthyes – fishes • Class Amphibia – amphibians (frogs and newts) • Class Reptilia – reptiles (snakes and lizards) (embryo surrounded by membrane & shell) • Class Aves – birds • Class Mammalia – mammals
Class Agnatha • Most primitive fish • Do not have a jaw (jawless fishes) • No fins or scales on body • Have no bones, only cartilage • Ex) Lamprey, hagfish
Class Chondichthyes • Means cartilaginous fish
Have no bones, only cartilage • Have fins and scales • Hinged jaw • No swim bladder Ex: sharks, rays
Class Osteichthyes • Bony fishes • Skeleton made of bone • Hinged jaw • Covered gill slits • Swim bladder to adjust buoyancy Ex: goldfish, tuna, halibut, etc.
Characteristics of Fish (Cartilage and Bony) • Breathe using gills • Have three chambered hearts • 2 atria and 1 ventricle • Reproduce sexually • Mostly external fertilization • Have fins- balance, steering, swimming • Have scales- thin bony plates
How fish breathe • Water is drawn in through the mouth of the fish. • The fish then closes the mouth and contracts the muscles in the mouth • Forces water past the gills and out past the gill covers.
Evolutionary Importance of Fish • Development of Jaws • Enables animals to grasp and crush prey • Development of Bone • Hard, mineralized living tissue that makes up the vertebrate endoskeleton • Development of Vertebrae • Major support structure for vertebrate skeleton, but still provided flexibility for movement. • Development of Teeth • Enables animal to rip, tear and grind up prey.
From Water to the LandWhat challenges would this present? Problems: Solutions: Cartilagebone Lungs Skin and scales Adapt ability to perceive sound, smell, and light differently • No support on land • Gills stick together • Desiccation • Sound, light, and smell is perceived differently on land
Class Amphibia • Includes salamanders, newts, caecilians, frogs, and toads
Class Amphibia • Not fully adapted for life on land • Rely on water for: • Reproduction (external fertilization in water) • Prevents desiccation • Ectotherms (cold blooded)- heat comes from external sources
Have 3 chambered heart (2 atria and 1 ventricle) • 1 ventricle means partial mixing of oxygenated and deoxygenated blood
Offspring develop my metamorphosis • Tadpoles (aquatic larva) resemble fish
Respire through poorly developed lungs and moist skin (more important)
Class Reptilia • Examples: Snakes, lizards, turtles, crocodiles
Characteristics • Complete life cycle on land • All have lungs • No longer need water for reproduction • Ectotherms (cold blooded) • Internal fertilization • Reptiles have scales on their skin • Prevent water loss and for protection
Most have 3 chambered heart with partially divided ventricle • Crocodiles have a 4 chambered heart
Develop from an amniotic egg • Yolk provides nourishment for developing embryo • Amnion is a membrane filled with fluid that cushions and prevents it from desiccation • Leathery shell for protection
Temperature determines the sex of hatchling green turtles (Cheloniamydas)
Archeopteryx believed to be evolutionary link between reptiles and birds • Have both reptilian and aves characteristics
Feathers (flight and insulation) • Evolved from scales • Scales on their legs • All have wings and most can fly some used for swimming
Takes in oxygen through lungs and air sacs • efficient for supplying high levels of oxygen to muscles during flight • Endotherm (warm blooded) • Hollow bones – lightweight for flight. • Lay amniotic eggs • Some parental care of eggs and young.
4 chambered heart • Separates oxygenated and deoxygenated blood
Class Mammalia • Internal fertilization • Most do not lay eggs but give birth to live young • Young are nourished with milk (rich in fat, sugar, proteins, minerals, and vitamins) that is secreted from mammary glands • Parental care • Have hair
Endothermic (warm blooded) • Have sweat glands to cool off. • Have lungs operated by a diaphragm. • Thin muscle that can increase the size of the lung cavity to allow breathing. • Highly developed brains • Capable of learning!
Includes humans, cats, dogs, etc… and also dolphins and whales • 3 Types of Mammals: • Monotremes, Marsupials, Placentals.
Monotremes- egg laying • Mammals that lay eggs instead of giving birth to live young • Eg. Platypus and the echidna
Marsupials- pouched mammals • Live birth • Premature young • Feed on milk in the pouch • Only females have pouches • Marsupials give birth to partially-developed young who then migrate to a special pouch in the mother's body • Ex: Kangaroo, Koala, Possum
Placental- nourishing plantea • Live birth • Fetus is nourished during development in the uterus by a placenta • Umbilical cord passes nutrients and oxygen to the developing embryo).
The offspring are carried in the mother's uterus until fully developed. • Humans - 9 months • Cats - 8 to 12 weeks • Dolphins 12 months • Elephant - 18 months
Phylum: ChordataClass: Mammalia Other Orders of Mammals • INSECTIVORA - hedgehogs, shrews and moles • DERMOPTERA - flying lemurs • CHIROPTERA - Bats • EDENTATA & PHOLIDOTA - toothless mammals, are exclusively American and contain the anteaters, tree-sloths and armadillos • LAGOMORPHA - the rabbits and hares • RODENTIA - mice • CETACEA –whales and porpoises • CARNIVORA – bears, dog, raccoons, weasels, cats • UNGULATES - hoofed mammals • PRIMATES – monkeys, humans