Vertebrates

Chapter 34

Phylum Chordata

• Dorsal, hollow nerve cord– Tubed ectoderm

• Notocord b/w GI tract and nerve cord– Fluid filled fibrous cases– Vertebral discs in humans

• Pharyngeal slits– Gills in aquatic animals– Head structures terrestrially

• Post-anal tail

Invertebrate Chordates

Subphylum Cephalochordata• Lancets• All characteristics as adults• Gas exchange w/ body too• Filter feeders w/ mucous

trap

Subphylum Urochordata• Tunicates or sea squirts• Characteristics & motile as

larvae– Degenerate to pharyngeal slits– Sessile– Mucus adaptation for feeding

Class Agnatha

Hagfishes• Cartilaginous skull

– Vertebrae absent– Segmental muscles use

notocord

• Weak vision, but developed touch– Slime glands – Knotting body

Lampreys• Fish parasites

– Larvae filter feeders– Invaded Great Lakes

• Jawless fish– Rasping tongue to ingest blood

• Cartilaginous skeleton– Vertebrae

Class Chondrichthyes• Cartilage endoskeleton w/ tooth-like scales• Jaws for grabbing and biting• Swift, unagile swimmers

– Paired fins w/ specialized functions– Continuous swimming for respiration

• Carnivorous for most part• Sharks

– Teeth replaced regularly– Enhanced vision, smell, and vibration– Internal fertilization w/varied results

• Rays– Venomous, barb-tipped tails

Class Osteichthyes

• Ossified endoskeleton w/ bony scales– Slime glands reduce drag

• Lateral line system detect vibrations• External fertilization• Operculum• Swim bladder• 2 Clades

Osteichthye Lineages

Actinopterygii• Ray-finned fish• Fins enhance

maneuverability and defense

Order Sarcopterygii• Lobe-finned fish• Linneages

– Coelocanths once thought extinct

– Lungfishes– Tetrapods

Class Amphibia

• Dual life stages– Herbivore tadpole w/ gills, lateral line system, no

legs, and long tail– Carnivorous adult w/ lungs, legs, and no tail or

lateral line system• Damp habitat

– Gas exchange– Eggs w/o desiccation protection

• External fertilization

Amphibian Orders

• Order Urodela– 4 equal limbs w/ side-to-side mov’t– E.g. salamanders and newts

• Order Anura– Powerful hind legs– Sticky tongue– Skin secretions and color variations– E.g. frogs

• Order Apoda– Legless and nearly blind– E.g. Caecilian

Class Reptilia

• Scales of keratin• Shelled eggs• Most ectothermic• Lineages

– Tuatara – Lizards– Snakes

• Vestigial pubic bone• Hunting adaptations

– Scales help grip– Sense ground vibration– Heat detecting organs– Venom

Class Reptilia (cont.)

– Turtles• Fused shell• Neck retraction

– No horizontal vertical

– Crocodilians– Birds

• Adapted to flight

http://potpourriwithrosemarie.wordpress.com/2011/06/10/is-it-an-

alligator-or-a-crocodile/

Class Aves

• Weight reduction– No bladder– Single ovary and small gametes– Lightened bones– Toothless

• Wings of keratin– Modified for flight types

• Endothermic – Modified circulatory, respiratory systems

• Developed brain and visual senses• Cloacal kiss

Class Mammalia

• Mammary glands• Hair of keratin• Endothermic • Long paternal care to teach survival skills• Differentiated teeth• 3 lineages

Monotremes

• Australia and New Guinea• 1 duck-billed platypus• 2 spiny anteaters• Lay eggs• Milk from glands w/o nipples

• Live birth early in development– Finishes in pouch w/ milk

supply• Most in Australia and

New Zealand– Opossums in North

America– Convergent evolution w/

eutherians

Marsupials

Eutherians

• Longer gestation = fully developed young• Convergent evolution with marsupials

Mammalian Orders

Order Primate Phylogeny

Order Primates

• Appendages– Limber joints– 5 flexible digits w/ opposable thumbs– Flat nails

• Reduced olfaction, enhanced vision• Increased parental care and smaller litters• 2 lineages

Prosimians

• Lemurs– Madagascar– Evolved in isolation– Primarily nocturnal

• Lorises– Africa and Southern Asia– All nocturnal

• Tarsiers– Southesast Asia– Carnivore

Loris

Ring-tailed lemur

Tarsier

Anthropoids

• Monkeys– Active by day– Social– Appendages all ~ same length– New World

• Arboreal • Long prehensile tail

– Old World• Ground dwelling and arboreal• Lack prehensile tail

• Hominoids (Apes)

Hominoids (Apes)

• Long arms and short legs• Lack tails• Mainly vegetarian

– Humans omnivorous• Larger brain to body mass ratio• High degree of socialization

Hominoid (Ape) Divisions• Gibbons

– Southeast Asia– Entirely arboreal apes– Smallest, lightest and most acrobatic– Monogamous for life

• Orangutan– Solitary species in rain forests of Sumatra and Borneo– Largest arboreal mammal, occasionally move on ground

• Gorillas– Largest ape, found only in African rainforests– Live in groups of up to 20– Stand upright, walk on 4 legs with knuckles on the ground

Hominoid (Ape) Divisions (cont.)• Chimpanzees (and bonoboos)

– Knuckle walkers– Tropical Africa– Behavior closely mirrors humans

• Make simple tools• Respond to mirrors

– Can learn human sign language• Humans

– Bipedal, larger brain, capable of language, thought, and complex tools

Evolution of Vertebrates

• Craniates– Cephalization w/ brain and sensory structures– Neural crest cells– Pharyngeal to gill slits

• Vertebrates– Extensive skull and vertebrae– Aquatic species w/ fins and enhanced gas exchange

• Gnathostomes– Hinged jaws w/ teeth– Aquatic species w/ lateral line system

Evolution of Vertebrates (cont.)• Tetrapods

– Pectoral and pelvic fins to limbs• Support weight on land• Digits to push ground

– Head separated from neck• 1st up and down (C1)

• 2nd side to side (C2)

• Amniotes– Amniotic egg w/ multiple membranes– Shelled eggs

• Leathery w/ reptiles• Calcified w/ birds• Mammals w/o b/c develops internally

– Thoracic breathing

Vertebrate Diversity Review

List characteristicsresponsible for each branch point (a-i)