Transcript Unit 11 Animal Evolution Chp 34 Vertebrate Evolution

CHAPTER 34
VERTEBRATE EVOLUTION
AND DIVERSITY
Phylum Chordata
Some Invertebrates
Deuterostomes
1. Notochord (disks)
-longitudinal, flexible rod between
digestive tube and nerve cord
-large, fluid filled cells/ stiff fibrous tissue
-support
-most vertebrates – only remains as “disks”
2. Dorsal, Hollow Nerve Cord
-develops from ectoderm that rolls into a
tube/ dorsally from notochord
-develops into the Central nervous system:
the brain and spinal cord
3. Pharyngeal Slits
-region of digestive tract posterior to mouth
“ “pharynx”/ pouches
-filter food for invertebrate chordates
-modified for gas exchange (in aquatic
vertebrates), jaw support, hearing, and
other functions
4. Muscular, Postanal Tail
Subphylum Urochordata (Tunicates/ Sea Squirt)
Sessile or Planktonic
Tunic (cellulose-like carbohydrate)
Larva
Subphylum Cephalochordata (Lancelet)
“Idealized” chordates
Small (few cm long)
Live in the sand
Suspension feeders
Swim like fish
Gas exchange mainly across regions of the external body surface
Subphylum Vertebrata
Larger size
Active lifestyle
Neural crest (form skeletal elements/braincase)
Pronounced cephalization
Vertebral column
Closed circulatory system
Endoskeleton
Axial skeleton (cranium, vertebrae, ribs)
Appendicular skeleton (support appendages)
Living/ Grows
Ventral, chambered heart (blood, arteries, capillaries)
Gills or lungs
*Adaptations for feeding, digestion, and nutrient absorption
Contribute to formation
of certain skeletal elements
(cranium/ vertebral column)
Dorsal, hollow
Nerve cord
Jaws/ 2 sets of paired appendages
4 footed
shelled, water-retaining egg
Agnathans
Class Myxini: Hagfishes
Jawless vertebrates
eel-like in shape
Most primitive living "vertebrates"
Bottom-dwelling scavengers
Slime producing glands
predate the origin of
paired fins, teeth, and
bones hardened by
mineralization
(ossification)
Cartilage (connective tissue)
Serpentine swimming
Class Cephalaspidomorphi:
Lampreys
larvae for years in freshwater streams
 migrate to the sea/lakes streams (anadromous)
Cartilaginous pipe surrounding the rodlike notochord
Toothlike structures (keratin)
Gnathostomes
Jaws
Paired fins
Tail
Active predators
Jaws evolved by modification of the skeletal rods
that had previously supported the anterior
pharyngeal (gill) slits
remaining gill slits =
respiratory gas exchange
YouTube - Evolution Of Jaws 1of5
YouTube - Evolution Of Jaws 2of5
YouTube - Evolution Of Jaws 3of5
YouTube - Evolution Of Jaws 4of5
YouTube - Evolution Of Jaws 5of5
Class Chondrichthyes: Sharks and rays
Cartilaginous skeletons
Sharp Bony teeth
Streamlined bodies
Powerful swimming muscles
Buoyancy by storing a large amount of oil in its huge liver
Animal is still denser than water, and it sinks if it stops swimming
Use muscles of the jaws and pharynx to pump water over the gills
Suspension feeders and Carnivores
Short digestive tract (spiral valve)
Acute senses (predation)
Sight good (no color)
Smell (nostrils)
Lateral line system (detect water pressure changes
Detect electrical fields generated by muscle contractions of animals
Entire body transmits sound to hearing organs of inner ear (no eardrum)
Internal fertilization (cloaca/ male claspers near pelvic fin)
Oviparous; they lay eggs that hatch outside the mother’s body.
Ovoviviparous; they retain the fertilized eggs in the oviduct.
Viviparous; the young develop within the uterus, nourished by placenta
Class Osteichthyes: The bony fishes
Ray-finned fishes, lobe-finned fishes, and the lungfishes
Ray-finned fishes
Lungfishes
Most numerous vertebrates
Bass, trout, perch, tuna, herring, etc.
Lungs connected to the pharynx
Ossified endoskeleton (calcium phosphate)
Fins supported by long flexible rays
of the digestive tract
Flattened, bony scales
Gills (main organs for gas exchange)
Lobe-finned fishes
Mucous glands
Aestivate (state of torpor).
Coelacanth
Lateral line system
Muscular pectoral and pelvic fins
Four or five pairs of gills
supported by extensions of the bony skeleton
Operculum (muscle movement)
Swim bladder
Flexible fins
Most oviparous
Tetrapods
Tetrapod Evolution
Coelacanth
Tetrapods
Adaptations to shallow water
Buccal pumping/ mouth breathing (lungfishes and frogs)
Leglike appendages
Acanthostega
Class Amphibia
Salamanders, frogs, and caecilians
Moist skin to carry out gas exchange
Eggs lack a shell (dehydrate)
External fertilization (most)
Complex and diverse social behavior
Rapid and alarming population decline (worldwide)
Order Urodela "tailed ones"
Salamanders
Aquatic and Terrestrial (as adults)
Walk with a side-to-side bending
swagger (resembling early tetrapods)
Order Anura "tail-less ones"
Powerful hind legs
Long sticky tongue
Camouflage
Skin glands (distasteful/poison mucus)
Brightly colored (poisonous)
Metamorphosis
Amniotes
reptiles, birds, and mammals
Adaptations to land (terrestrial)
Amniotic egg (shell)
Extra embryonic membranes
Waterproof skin
Increasing use of the rib cage to ventilate the lungs
Class: Reptilia (lizards, snakes, turtles, crocodiles)
Scales (protein keratin)
Lungs
Shelled amniotic eggs (land/ leather)
Internal fertilization
Viviparous (some lizards and snakes)
“Cold blooded”
Ectothermic (basking)
Dominant terrestrial vertebrates for
+200 million years
Dinosaurs and Pterosaurs
Social behavior and parental care
Endothermic?
key differences between the three
groups in their skull anatomy
Order Testudines (turtles)
Hard shell
Lay eggs on land
Order Squamata (lizards and snakes)
Lizards
Most numerous and diverse reptiles
Relatively small
Snakes
Descendants of lizards that adapted
to a burrowing lifestyle (vestigial limbs)
Order Crocodilia (alligators and crocodiles)
Limbless
Carnivorous
Among the largest living reptiles
Acute chemical sensors
Upturned nostrils
Lack eardrums but sensitive to ground vibrations
Heat-detecting organs between the eyes and nostrils of pit vipers
Toxin through a pair of sharp hollow or grooved teeth
Tongue (olfactory organs on the roof of the mouth)
Loosely articulated jaws
Class: Reptilia (lizards, snakes, turtles, crocodiles)
Order Testudines (turtles)
Order Squamata (lizards and snakes)
Order Crocodilia (alligators and crocodiles)
Class: Aves (birds)
Amniotic eggs and scales on the legs (reptilian features)
Flight
Bones are honeycombed (light)
Absence of some organs (one ovary)
Toothless
Gizzard grinds food (crocodiles/dinosaurs)
Beak of keratin (adaptations)
Active metabolism
Endothermic
Feathers (retain heat)
Advanced circulatory (4 chambered heart)
Advanced respiratory
Acute senses
Sight (possibly the best)
Motor skills/ coordination
Social behavior
Internal fertilization
Archaeopteryx
Carinates (keels)
Ratites (no keel)
Passeriformes
“perching”
Large pectoral (breast) muscles anchored to a keel
on the sternum (breastbone)
Feathers (endothermy and flight)
Class: Mammalia
Mammary glands
Hair (keratin)
Endothermic
Circulatory-4 chambered heart
Respiratory-diaphragm
Fat (retain heat)
Differentiation of dentition (teeth)
Internal fertilization
Inner ear (from jaw bones)
Birth (some placenta)
Large brains
Cognitive abilities
Extended parental care
Monotremes (platypuses spiny anteaters)
Egg laying (reptilian like)
Milk and hair
Eutherians (Placental)
No nipples (just glands)
Longer gestation (pregnancy)
Marsupials (Opossums, kangaroos, koalas)
Early birth
Pouch (marsupium)
Austraila
Platypus
Spiny Anteater
Therapsids
Order: Primates
Grasping hands
Opposable thumb (big toe)
Larger brain
Flattened face
Stereoscopic vision
Nails
Finger skin ridges (prints)
Extended parental care
Complex social behavior
Coordination
Flexible joints
Prosimians
Lemurs
Bushbaby
Tarsier
New World
Monkeys
Old World
Monkeys
Orangutan
Gorilla
Hominoids
Great Apes/ Humans
Chimpanzee
Bonobo chimpanzee
Hominids
Australopithecines
~5 – 2 mya
Homo habilis
~2 – 1.5 mya
Homo erectus
~1.6 mya
Homo sapiens
~400,000 – 100,000 ya
Bipedalism
Larger brain (~400 cm3  1300 cm3)
Shorter jaws
Dentition
Sexual dimorphism (male size to female)
Extended parental care
Family structure
Learning
“Lucy”
~5 million years of Evolution
Pan troglodytes
Homo sapiens
Human
Diversity
Homo sapiens