Lecture Exam 1 Flashcards
Analogy
Similar function
e.i. Bird and bat wings
Homology
Common ancestry
e.i. Forelimbs of bird and crocodile
Homoplasy
Similar appearance
e.i. Sail fin on fish and sail back reptile
Homocercal tail
Dorsal and ventral same size, provides thrust, found with swim bladder
Heterocercal tail
Dorsal bigger then ventral, provides lift, found without swim bladder
Archaeopteryx
Have both reptile and bird traits
Lobe fin
Preadapted to evolve to tetrapods
True chordate fila
Cephalochordata, urochordata, vertebrata
Fila with some chordate feature
Hemichordata
Chordate features
Notochord,dorsal hollow nerve cord, pharyngeal slits, post-anal tail, endostyle/thyroid gland
Endostyle
Mucus producing
Thyroid gland
Hormone producing
Notochord
Fluid filled cells, rigid/flexible = structure/movement, early in embryos but degrade in adults, under dorsal hollow nerve cord
Pharyngeal slits
Behind buckle cavity in pharynx, exit for filter feeding, embryo in mammals
Protocordates
Hemichordates, chephalochordates, urochordates
Deuterostomes
Develop anus then head
Hemichordates
Pharyngeal slits develop differently, anus at tip of tail, collar nerve cord (develop differently, ciliary mucus feeder, body plan (proboscis, collar, trunk). e.i. Acorn worm
Hemichordates larvae
Free swimming similar to echinoderm
Cephalochordates
Marine, closer to Hemichordates
e.i. Amphioxus, lamprey
Urochordate
Adults lack tail and notochord, branchial basket (pharynx), closer to vertebrates. e.i. Tunicates, larvacea, “sea skirt”
Larvacea
Urochordate, release mucus that creates “house”
Origin of chordate body plan theories
Anthropod/annelid ancestor or echinoderm ancestor
Anthropoid ancestor to chordates
Segment, ventral not hollow nerve cord (flipped), false
Echinoderm ancestor to chordates
Hemichordates larva similar to echinoderm larva, bilateral symmetry, deuterostomes (Gastang)
Echinoderm larva. How is notochord formed?
Similar to chordates but elongated (ciliary bands form nerve cords
Larva sizes
Locomotion (cilia then segmented muscles and notochord), feeding changes (adoral band/cilia use endostyle then water intake use pharyngeal slits)
Paedomorphosis
Juvenile able to breed. e.i. Salamander
Ancestor of chordates
Echinoderm
First complex life
542 mya
First vertebrate/chordate
.5 bya, Cambrian period in Paleozoic era
Fossil types
Impression and mineralized
Impression
Fine silt
Mineralized fossils
Hard structures convert to rock
Dating fossils
Stratigraphy (comparison) and radioisotopes (uranium to lead and potassium to argon)
What can you find out from fossils?
Behavior/social interactions, fair, skin texture
Ostracoderms
Early fish, jawless
Placoderm
Jaw fish
Early Paleozoic
Ostracoderms, placoderm
Chondrichthyes
Shark, cartage skeleton
Osteichthyes (types)
Bony fish, types: sarcopterygian and actinopterygian
Sarcopterygian example
e.i. Lung fish and coelacanth
Actinopterygian example
e.i. 1. Sturgeon, paddle fish, bichirs 2. Gars, amia 3. Salmon, perch, bass, etc…
Late Paleozoic
Chondrichthyes, Osteichthyes, tetrapod
Describe first tetrapod. (Years ago)
Amphibian-like 400 mya (e.i. Acanthostega with polydactyl digits), reptile 270 mya
Endothermic bones
Have osteons
Osteons
Long cylinders in bones
Ectotherm bones
Have growth rings
Early tetrapod bones
Rings but not osteons
Dinosaur bones
Osteons but no definite growth rings
Turbinates
Nasal conchae, warms and moistens air and recover moisture during exhalation (dinosaurs don’t have)
Primitive vertebrae
Protect neural tube: arches around neural tube, ventral arches around arteries, prominent notochord
Arcualia theory of vertebrae development
Evolutionary fusion of blocks, false: tetrapods develop differently
Resegmentation
Somite grow in repeated units down neural tube, separate into pieces (dermis, body, vertebrae), vertebrae grow around notochord-perichordal tube, resegment (.5 and .5), notochord degenerates
Vertebrae formation theories
Shark arculia and resegmentation (true)
Aspidospondyly
Vertebrae spines and centra are separate, primitive/flexible. e.i. Rhachitomous
Holospondyle
Vertebra and centrum connected, firm/weight baring, e.i. Lepospondyle
Bowfish
Have both aspidospondyl and holospondyl
Early placoderm vertebrae
Larger notocord but increased vertebrae
Chondrichthyes vertebrae
Reduced notocord but still present
Fins and girdles purpose
Muscle attachment, bone or cartilage
Limbs and girdles purpose
Stabilize limbs, carry propulsive force, muscle attachment
Part fins to limbs
Basal-stylopodium, radials-zeugopodium, dermal-autopodium
Theories for fins to limbs
Gill arch theory and fin fold theory
Gill arch theory
(Karl Gegenbaur) extend gill ray to become fins, what about pelvic fins?
Fin fold theory
(Francis Balfour) ventral ridges/fin folds in Agnathans stiffened by internal structures
Why evolve fins?
Streamline but balanced: pitch, yaw, roll
Pitch
Up down force
Yaw
Left/right force
Roll
Force that turns over
Ostracoderms other features
Early Agnathans, no pelvic girdle, reverse heterocercal tail (not active)
Primitive bony fish
Have pectoral and pelvic girdle, active
Modern shark pectoral girdle
Basals fuse to form
Bony fish pectoral girdle
Most dermal bone, small amount endochondral none, port temporal attach skull
Dermal bone
Beneath skin
Endochondral bone
Cartilage to bone
Modification after fin to limb
Pelvic/pectoral girdle modest in fish and weight bearing in tetrapod, early tetrapod dermal reduced and not attached to skull (force not passed to skill)
Coelacanths
400 mya (thought extinct 65 mya), found to still be alive, hover and stabilize water column using lobe fins, 2 species (Africa and Indonesia)
Coelacanth discovery
1930s: Courtney Latimer caught in S Africa. 1950s: another caught and preserved
Pectoral girdle dual origin
endochondral component - basal fin elements (articulation and attachments) and dermal - dermal armor (brace)
Lobe fin
Preadapted into limbs
Why move to land?
Escape predation or aestivation but stay in water
Catfish and mud puppies
Modified/elongated pectoral fins, moved forwards, mud puppies hold water in mouth
Pectoral girdle pieces
Scapula, procoracoid, coracoid
Pectoral girdle modification
Endochondral component becomes more prominent
Pelvic girdle bone types and fusion
Only endochondral, fuse with adjacent vertebrae to stabilize (forces distributed to vertebrae)
Pelvic bones
Pelvis, ischium, ilium
Synapsids to mammals
Excavation (lighter because holes), orientation (align forces with travel direction), pubis/muscles reduced
Synapsids
Mammal-like tetrapod
Biomechanics
How form and function are related to engineering
Forces
Static (gravity) and dynamic (motion)
Compression
Push together
Tension
Pull apart
Shear
Opposing forces (bend in half)
What forces can bones resist most?
Compression > tension > shear
Microfractures
Imperfections concentrate forces
Leading
How forces are distributed
More stable leading
Asymmetrical leading
How to prevent breaks
Counter weight, bigger brace (e.i. Tendon-iliotibial tract)
Continuous force
Atrophy. e.i. Tumor
Unstressed force
Atrophy. e.i. Astronaut
Intermittent force
Hypertrophy. e.i. Normal
Atrophy
Reduction bone mass
Hypertrophy
Increased bone mass
Stressed trajectory
Focused at periphery, forms compact bones
Trabeculae
Spongy bone
Wolf’s Law
Bone remolding proportional to mechanical forces applied
Piezoelectricity
Negative charge = bone depression = compression
Why biped locomotion?
Height,sight, more forelimb use
Modifications for bipedal locomotion
Feet have arches, legs further apart, shorter pelvis, s-shaped vertebral column, axial muscles and ligament stabilization
Foot arches
Weight spread out
Legs further apart
Femur angled, allows balance
Shorter pelvis
Lowers waist and center of gravity
A-shaped vertebral collumn
Shock absorber
Suspension support
Static support
Resist compression
Neural spines and centra
Resist tension
Muscles/ligaments
Biological node
Reversal of neural spine direction
Counter balance
Tail
Expanded cervical
Increase head movement
Separate lumbar
No interference with hind limbs
Streamlining
Reduce drag to maximize propulsion
Lateral undulation
Used by fish, amphibians, and reptiles
What organisms use cursorial motion?
Mammals and dinosaurs (developed separately)
Therapsid modifications
Limbs/digits rotated forward (direction of travel), limbs under body
Limbs under body
Ease of motion, pendulum swing (adductor reduced), developed independently in dinosaurs
Lateral sequence gate
3/4 limbs in contact together, stable
Speed =
Stride length x stride rate
Increase stride length
- Distal elements lengthen 2. Foot posture with less contact 3. Joint addition to locomotor mechanism 4. Increase flexion
Flexion
Distance limbs move while off ground
Increase stride rate
- Muscle location 2. Muscle mass (lighten distally) 3. Digit reduction (lighten distally)
Lighten distally
Reduce inertia
Gates
Pattern foot touches ground
Amble
Forelimbs and hind feet move in unison
Fast amble
Pace
Troy
Diagonally opposite limbs move together
Half-bound
Hind feet contact a same time, forefeet lead and trail
Gallop
All feet leading and trailing, high speed
Print (bound)
All four in unison, decelerates
Larger animal travel
Less flexion, less energy, endurance
Smaller animal travel
More energy, speed
Ariel locomotion
Movement through air
Jumping
Escape predators
Parachuting
Increase drag, soft impact
Gliding
Deflect line of fall, increase lift
Flailing
Increase distance
Classes with powered flight
Birds, bats, pterosaurs
Flying squirrel
Gliding skin
Pigmy opossum
Parachuting cup body
Colugo “flying lemur”
Largest flap of skin includes tail and fingers
Flying frog
Webbed feet
Flying lizard “flying dragon”
Long ribs
Flying snake
Flatten ribs into cup shape
Flying fish
Large pectoral fins
Bats
Fold of skin (body to digits), manis only in wings not whole arm
Pterosaurs
Sparrow size to 40 ft wing span, membrane extends to elongated 5th digit
Birds
Most efficient adaptations, primary and secondary feather
Origin of flight hypotheses
Arboreal, insect net, and climbing
Insect-net theory
running with short hops, wings used to catch insects/small prey
Climbing theory
Wing assisted incline running motion same as flying motion. Archaeopteryx don’t have claws for climbing
Bernoulli’s principle
As fluid velocity increased, pressure fluid decreases
Airfoils
Allows separation of fluid velocities
Cambered wing
Front of wing thicker; air flows over top faster, decreases pressure while under pressure increases causing lift
Horizontal wing
Lift greater then drag
Partially Angled wing
Lifts more but also more drag
Extremely angled wing
Decreases lift and increases drag
Secondary feathers
Forearm, lift
Primary feathers
Phylanges, thrust
Soaring vs thrust wings
Thrust increased manus and thrust, soaring increased forearm and increase lift
Soaring wing shape
Long (lift)
Pheasant win shape
Short/rounded wing (maneuverable)
Swallow wing shape
Streamline (streamline/fast)
Hawk
Intermediate shape (maneuverable/lift)
Penguin wing bones
Robust wing with thick bones (swimming)
Auk wing bones
Medium bones (blinking)
Sea gull wing bone
Thin/long bones (soaring)
Synsacrum
Rigid skeleton resists aerodynamic forces
Why fly?
Travel distances/migrate, catch prey
Tubular hollow bones
Lighten skeleton
Synsacrum parts
Sacrum and pelvic girdle
Early Mesozoic (200 mya)
True amphibians and true reptiles
True amphibians
Frogs, salamander, and caecilians
True reptiles
Turtles, crocodiles, squamatrs, tuatara
Tuatara
Reptile from Jurassic period
Age of reptiles
Mesozoic
Ichthyosaurs
Dolphin-like, 30 ft long, air breathing through mouth
Plesiosaurs
Pattle-like limbs, air breathing, 2 types: long 70 vertebrae neck and short neck. e.i. Loch Ness
Pterosaurs
Powered flight, pinky extended to become wing, coastal, needle teeth
Dinosaur types
Saurischians and ornithischians
Saurischians
Ischium hip down, “lizard hip”
Ornithischians
Ischium hip back, “bird hip”
Stegosaurs
Plates down back (heat/protection) and spiked tail
What caused dinosaur extinction?
Volcanism, climate, vegitation, asteroid
Asteroid
Eukenane peninsula 65 mya
Age of mammals
Cenozoic
Mesozoic-Triassic
First mammals
Lineages of mammals
Monotremes, theria, eutheria
Monotremes
Lay eggs. e.i. Platypus, spiny anteater
Theria
Pouched marsupials
Eutheria
Placental mammals
Saber-toothed mammals
2 Placental (e.i cat and nimravid cat-like) and 1 marcupial
Late Cenozoic
Humans
Human species
Homo habalis (“handy man”), homo erectus, homo ergaster, homo neanderthalensis, homo sapien
Homo neanderthalensis
Extinct 10-12 thousand years ago
Homo sapien
100 thousand years ago
Mid-Cenozoic
Decline in North American mammal diversity
Ectotherms
“Cold blooded”
Endotherms
Warm blooded
Predictor prey ratio of dinosaurs
Less predators shows endotherm. Cod be chance fossils
Insulation of dinosaurs
Feathers first in dinosaurs. Shows endotherm. Could be sexual
Latitudinal distribution of dinosaurs
Spread to poles shows endotherm. Could be migration