• They are all forms of regulating body heat
• Ectothermy - body temperature shifts with the environment (many reptiles, turtles)
• Endothermy - body heat is regulated by internal metabolic processes (seals, penguins, humans)
• Poikilothermy - internal temperature varies considerably, dont undergo homeostasis (fish, amphibians, reptiles)

What is Q10 and how is it related to changes in metabolic rate? Draw a graph to show

this relationship. (1)

• Q10 is the ratio of the rate of reaction at one temp compared to the rate at a temp that is 10degrees higher or lower
• [image]

• Complex of arteries and veins lying close to each other
• utilizes countercurrent blood flow within the net
• exchanges heat, ions, or gases between vessel walls so that two bloodstreams within the rete maintain temp gradient

What are the main synapomorphies for Osteichthyes? Who are the osteichthyes? (2)

• Osteichthyes are the bony fishes
• Synapomorphies
  • patterns of lateral line canals
  • opercular and pectoral girdle elements
  • fin webs with dermal rays
  • endochrondral bone

• Duration - 48 million years
• Age of fishes
  • co-existance of all major lineages of fishes, marine and fresh water
  • abundant fossils
  • major innovations
    • feeding mechanisms

What is the relationship between feeding mechanisms and other evolutionary changes

in bony fishes? (1)

• major innovations
  • feeding mechanisms
    • locomotion
    • habitat
    • behavior
    • life histories

Name the two major lineages of bony fishes and describe how they differ from one

another. (2)

• Actinopterygians - ray finned fishes
  • one dorsal fin
  • fins are supported by bony or horny spines
  • fins attach directly to internal skeleton
• Sarcopterygians - lobe-finned fishes
  • two dorsal fins
  • fleshy, lobe shaped fins

• symmetrical tail fins
• reduction of bony rays in fins
• reduction of external armor 
  • decreased weight, decreased locomotion
• lungs - sophisticated swim bladder
• changes in jaw bones and musculature
• snapping jaws - protrusable jaws

• Began as outpocketing of the gut
• could have evolved separately, or one could have evolved into another

• Catadromous
  • migrate to oceans to reproduce

• Anadromous - live in ocean and reproduce in fresh water
• Catadramous - live in fresh water and reproduce in ocean

How might environmental temperature be responsible for differences in growth, development, and morphology (number of vertebrae) between American and European eels? (4)

• lower temperature slows down growth and development in European eels compared to American eels, so it takes longer to reach the same size

What main physical forces (drag) do aquatic vertebrates such as fish need to overcome, and how do they overcome them (adaptations in body shape and fin shape, etc.)? (3)

• Viscous - from friction
  • Relatively constant
  • Adaptations - smooth surface, mucus
• Inertial - from pressure diff. created by fish's displacement of H2O
  • Increases rapidly with increasing speed
  • Adaptations - body shape

What are the main differences in reproductive strategies between marine and fresh water fishes? What could explain these differences? (4)

What factors explain the differences in diversity in number of fishes in different regions of the ocean, including depth? (1)

• Factors such as depth, amount of light, availability of food energy
• Challenge in the ocean - photosynthetic producers are only found at less than 100 meters deep
  • Any organisms found below this level depend on a "rain of debris" from surface, which decreases depth due to consumption
• As depth increases, fish decrease in abundance, size, and diversity

• Huge diversity in feeding modes and ecological niches
• Strong selective pressures on interaction between feeding and locomotion in the complex structure of the coral reef
• High visual activity
• Lots of shelter and escape routes allows diurnal behavior and the evolution of gaudy coloration = signals
• Essentially, precise partioning of space, time, and available food resources

• Reproductive isolating mechanisms (RIMs)
  • Post-zygotic - inviable or sterile offspring
  • Pre-zygotic - prevention of mating
• Offspring can't reproduce, or don't live to maturity, or they can't even mate at all

• Freshwater fishes
  • Destruction of adult and/or larval habitat directly or indirectly from human activities
  • Pollution
  • 20% to 80% of native fresh water species in the US are imperiled
  • Currently, there are too few researchers
• Marine fishes
  • Major commercial fisheries
  • Drastic fluctuations in population size makes it difficult to make predictions
  • Means sometimes over fished and populations are destroyed

• Sarcopterygians - fleshy-finned fishes
• Actinistia: Coelacanths
  • Deep water marine; W. Indian ocrean and Central Indonesia
• Dipnoi: Lungfish
  • Fresh water; S. hemisphere (S. American, Africa)
• Tetrapods
  • Terrestrial, semi-aquatic, secondarily aquatic; world-wide

How have climates changed over geologic time? What could be the effects on vertebrate

evolution? (1)

• Cold and dry compared to past times
• Changes in interaction of sunlight, temperature, rainfall, evaporation and wind
• Position of continents affects flow of ocean currents which contain a lot of heat which affects climates world-wide
• Continental drift is imporant! - when continents moves towards the poles, they have cooler climate
• Geological factors - mountains, barriers - affect climate
• Changes in climate forced them to move on land because things were dry

What selective pressures could help explain the invasion of land by ancient sarcopterygians? Were these fish or tetrapods? How can we tell? (2)

• Drier, colder climate, continental drift
• Features useful for land evolved in aquatic environment because they were advantageous for animals that were still living in water, not because they would someday be useful for animals that lived on land
• Limbs would have been useful to large aquatic predators for creeping along the bottom

• Acanthostega: extremely fish-like
• Ichthyostega: less fish-like
• Characteristics:
  • Both clearly aquatic
  • Internal fish-like gills
  • Lungs
  • Limbs show polydactyly, probably used as paddles

What sorts of changes in the skeleton (esp. limbs and vertebrae) accompanied the

invasion of land by sarcopterygians? (2)

• Tetrapod limb evolved from fish fin
• Pelvic girdle is fused to modified sacral vertebrae
• Opercular and gular bones that attach pectoral girdle to back of head in bony fishes are lost
• Main endochondral bones are scapula and coracoid
• Pectoral and pelvic fins of fishes become limbs of tetrapods

• Mode of reproduction
  • Became direct-developers
• Formation of lungs and trachea
• Presence of urinary bladder
• Length of neck and length of snout

• Paradox: fossil vertebrates with limbs were capable of locomotion on land but had gills that could only work on water
• No way of knowing how a land animal could evolve in water

• fertilized egg is surrounded by vitelline membrane, inner jelly capsule, and outer gelatinous envelope
• Jelly-like egg - just like fish!
  • Jelly nourishes egg

• Caudata (Urodela): Salamanders (and newts)
• Anura (Salientia): Frogs and toads
• Gymnophiona (Apoda): Caecilians

• Structure of skin and cutaneous gas exchange
• Papilla amphibiorum - special sensory area, detects sound frequencies
• Operculum-columella complex (ear bones)
• Green rods in retina 
• Pedicellate teeth - composed of dentine
• Structure of eye muscle (levator bulbi) - causes eye to bulge outward to increase mouth cavity size

What is the importance of skin adaptations in the Lissamphibia? And what are these adaptations? (3)

• Amphibian exchange of oxygen and carbon dioxide with environment takes place through the skin
  • Helps them breathe!
• Mucous glands
• Poison (granular) glands
• Permeable, unadorned skin

• Heart is separated into two chambers for oxygenated and deoxygenated blood
  • Blood from lungs (oxygenated) flows into left side
  • Blood from veins (deoxygenated) flows into right side
• Atria pump blood out of heart and where it is needed
• Ventricle has a mechanism for separating oxygenated and deoxygenated blood to the left and right chambers of the heart
• There is not need for a second ventricle, and works best for their mode of respiration

• Hind legs are elongate, and tibia and fibula are fused to help catapult them into the air
• Powerful pelvis that is strongly fastened to the vertebral column
• Ilium is elongate
• Posterior vertebrae are fused into a solid rod, the urostyle
• Vertebral column is short
• Strong forelimbs to absorb impact of landing

• Nearly 5400 species and occur on all continents
• Can live in a broader range of environments
• So many different kinds
  • direct developers vs. aquatic larvae
  • lungless vs. lungs

• Pupidae - "clawed frogs"
  • Pipa pipa
• Bufonidae - "toads"
  • American toad
• Ranidae - "true frogs"
  • Bullfrog
• Hylidae - "tree frogs"
  • Peeper
  • Mexican treefrog
• Dendrobatidae - "dart poison frogs"
  • Poison dart frog

• Mostly external via amplexus, but also cloacal kisses
• One intromittent organ
• Larger eggs - means need for mode of protection
  • Lay eggs on leaves of trees overhanging water
• Marsupial Frogs
  • Carry eggs around on their back (sometimes in pouches)
• Some are even direct-developers and skip metamorphasis
• Gastric brooding frog - frog who swallows eggs and pukes them up

• Sirenidae
  • Lesser sirin, dwarf siren
• Cryptobranchidae
  • Hellbender
• Amphiumidae
  • Three-toed amphiuma
• Plethodontidae (lungless salamanders)
  • Red-backed salamander
• Dicamptodontidae
  • Pacific giant salamander

Why is genome size an important issue when considering morphological evolution in salamanders? (4)

• As genome size increases
  • Development rate decreases
  • species move from having aquatic larvae to become direct developers
• Large genomes slow depelopment (which decouples growth and development)

Who are the plethodontids and why are they important? What are the main evolutionary trends in plethodontid salamanders? (3)

• Lungless salamanders
• Largest salamander taxon
• Mostly direct--developers, some have aquatic larvae
• Lunglessness (skin specialized as respiratory organ)
  • Most successful family
• Nasolabial groove
• Tongue projection mechanism
  • Hypobrancial apparatus becomes specialized to allow this

What are some distinguishing characteristics of caecilians that make them unique

among amphibians, and even among vertebrates? (1)

• Legless, tailess, have tenticles, vestigial eyes

• Anything that disrupts gene exchange within or between populations can lead to speciation
• Genetic isolation leads to speciation

• Base group: Sarcopterygian fishes
  • Tetrapody, eyelids, muscular tongue
• Anura,Caudata, Gymnophiona
  • Shortened ribs, hand with 4 digits, poison glands in skin
• Gymnophiona
  • Sensory tentacle, girdles and limbs absent, reduced eyes
• Anura and Caudata
  • Loss of external dermal bone
• Anura
  • Loss of tail in adult, hindlimbs longer than forelimbs, fusion of tibia and fibula