practical 3

Lungfishes (in lobed finned fish category)

• SYNAPOMORPHY= LOBED FINS ?? 

• humans and tetrapods share a common ancestor

  • humans share a similar limb pattern as lungfishes

    • one long bone, two bones, wrist, digits

  • lungfishes are more closely related to humans than other animals

amphibians

• SYNAPOMORPHY= FOUR LIMBS WITH DIGITS 

• salamanders, frogs, caecilians

• tetrapods = four limbs with digits

  • Many live in water and land, but not all 

  • undifferentiated, single-pointed teeth

• not reptiles!

juveniles: 

• have gills 

• swim tail 

• webbed feet

• swim like fish 

adults 

• may have lungs for air 

• moist skin 

• needs water for reproduction 

amniotes

• includes: reptiles, mammals, birds

• amphibians and amniotes split from a common ancestor 

  • Amniote eggs develop on land, no need for water, but require moisture.

• Extra membrane layers outside the embryo allow for development inside the enclosed egg. 

  • gas exchange 

  • waste excretion 

reptiles

• SYNAPOMORPHY= AMNIOTIC EGG

includes: snakes, lizards, alligators, turtles, robins, etc. 

•Amniote eggs

•Breathing efficiency

•improved in amniotes due to the use of a rib cage to ventilate the lungs

•less dependent on gas exchange through the skin

•Leathery/ Dry skin (Keratinized cells)- less water loss through skin

•Kidneys – More concentrated Urine, less water loss

aves (birds with vertebrates)

• SYNAPOMORPHY= FLIGHT AND FEATHERS

includes: peacocks, penguins, seagulls 

• origins of flight arose 4 times

  • pterosaurs (flying reptiles)

  • bats

  • insects

  • birds

• 2 theories

  • tree-down hypothesis = tree-down hypothesis proposes that flight evolved from tree-dwelling ancestors who first glided down from heights before developing powered flight

  • ground-up hypothesis = flight evolved from fast-running ground animals using wings for balance and lift

• lungs + air sacs, 4-chambered heart

• one ovary

• no teeth

• warm-blooded

mammals

• SYNAPOMORPHY= warm blooded + high metabolisms + fat layer under skin for insulation + sweat glands to cool

• efficient respiratory and circulatory systems

• legs move under body

• specialized teeth (shearing, crushing, or grinding) —> food

• hair

• mammary glands (milk to feed the young)

• auricles (pinna) = external earlobes

• extended care of young

• more learned behaviors

Cyclostomes (jawless fish)

• SYNAPOMORPHY= SKULL AND BACKBONE COMPOSED OF VERTEBRAE

• craniates with simple vertebrae but jawless 

  • mixini - hagfish (not a fish) 

  • have cartilaginous, skull, and simple vertebrae

• some of these fish attach to fish and eat their blood

Chondrichthyes (cartilage fish)

• SYNAPOMORPHY= TRUE JAWS, FIRST BONES

• most are carnivores that have several rows of sharp teeth for tearing flesh

• acute sense of sight and smell ability to detect electrical fields aid in prey capture

• Sharks are swift swimmers but don’t maneuver well

• paired pectoral and pelvic fins are for maneuvering

• oil stored in liver for buoyancy but continual swimming is necessary to avoid sinking + gas exchange

actinopterygii (ray-finned fishes)

• SYNAPOMORPHY= LUNGS or LUNG DERIVATIVES

• include nearly all familiar aquatic Osteichthyes (bony-skeleton fish)

  • breathe water over gills

  • control buoyancy with air sac —> swim bladder

  • skin secretes mucus and is covered by flattened, bony scales in most fishes

• Fins are supported mainly by long, flexible rays and are modified for maneuvering, defense, and other functions
  
  

actinistia (lobed-fins)

• SYNAPOMORPHY= HINGED INTRACRANIAL JOINT IN SKULL THAT ALLOWS THE FRONT PART OF HEAD TO MOVE INDEPENDENTLY FROM REAR

• rod shaped bones surrounded by thick layer of muscle in pelvic and pectoral fins 

• lobed fins may have been used by ancient species to amneuver across the substrate of aquatic habitats

Echinodermata

• SYNAPOMORPHY= Pentaradial symmetry, water vascular system, endoskeleton

• marine animals

• includes starfish, sea urchins, sea cucumbers