BIOLOGY 202: DIVERSITY OF LIFE II – ANIMALIA
 from 2016 class Google doc
1. Introduction
Embryogenesis:
https://www.youtube.com/watch?v=G2HvEGUYwAU
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Four main steps:
Cleavage:
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Zygote divides to form a blastula (a fluid-filled ball)
Cells at the top (animal pole) are smaller and darker coloured; cells at the bottom
(vegetal pole) are larger and contain more yolk (nutrients provided by the ovary)
Cells remain unspecialized (totipotent)
Gastrulation:
o Cells of the blastula move inward at the blastophore to form a gastrula, a fluid-filled ball
with 3 cell layers
 Endoderm (gut lining and derivatives, germ cells)
 Ectoderm (epidermis, nervous system)
 Mesoderm (everything else)
The 3 body axes are now defined:
o The blastophore will form the anus; the mouth will form at the opposite end
(‘deuterostome’)
o The animal pole will form the back; the vegetal pole will form the abdomen
o Cells are still totipotent, but their fates are determined
Neurulation:
o Dorsal mesoderm cells aggregate into a rod-like structure (notochord – support)
o The notochords induces the dorsal ectoderm to fold, forming:
 The dorsal neural tube (central nervous system)
 Neural crest cells (other nervous system components)
Mesoderm flanking the notochord becomes segmented into somites (skeleton, skeletal muscle)
Pharyngeal pouches form along the pharynx (gills, thyroid)
The brain differentiates into 3 lobes (five brain lobes)
Ectodermal placodes form at the head (eyes, ears, nostrils)
The final product of neurulation (neurula or pharyngula) is very similar in all vertebrates
Organogenesis:
o Longest stage in all animals
o Embryonic cells specialize, forming tissues, organs and organ systems
 Differential cell division, growth and death results in different body shapes
2. Organ Systems
https://www.youtube.com/watch?v=dZQMjZRv16E
1.
Integumentary system: functions in protection, communication (pheromones,
sending/receiving information with environment), respiration, excretion,
osmoregulation
a. Includes two main multicellular layers (epidermis and the dermis),
blood vessels, nerves, mucous glands
2. Skeletal system: functions in support, protection and movement
a. Originally made of cartilage and included only gills and axial skeleton
(notochord, cranium and vertebrae)
b. Bone appeared early in vertebrate evolution
i. Endochondral (laid down within cartilage)
ii. Dermal (laid down by the dermis)
3. Muscular system: functions in support and movement
a. Includes three muscle types:
4.
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i. Smooth (involuntary; usually visceral)
ii. Striated (skeletal; usually somatic, multinucleate)
iii. Cardiac (heart)
Digestive system: functions to release nutrients from food, process and store
nutrients, and neutralize toxins
a. Originally included only the mouth, pharynx (everything comes
together), esophagus, stomach (except in lamprey- Petromyzontida),
small intestine (nutrient absorption), liver (nutrient stored and
transported to blood), pancreatic cells and cloaca (exit)
b. Intestinal lining is folded into villi and microvilli (increase surface area
for better absorption); also have general folds which slow food down
and help mix it
c. Food is moved through the gut by peristalsis (contraction around gut
wall; smooth muscles run both around tract and up/down it)
Respiratory System: functions to exchange O , CO , heat, salts and N
wastes
a. Originally involved the skin and vascularized foldings of the pharynx
(gills) with muscles for pumping water
Circulatory System: transports oxygen, nutrients, wastes, hormones,
antibodies, and heat
a. Is closed, originally single circuit
b. Originally the heart had 4 chambers (only one atrium and one
ventricle,plus conus arteriosis (muscular, prevent backflow) and sinus
venosus (collect blood from veins)
c. Lymphatic system recovers fluid and nutrients lost from the capillaries
Excretory System: functions in osmoregulation and elimination of metabolic
(nitrogenous) waste
a. Originally included the kidneys, skin, gills, and intestine
b. Functional unit of the kidney is nephron (a tubule lined with
specialized cells for filtering wastes from blood)
i. Bowman Capsule à renal tubule à collecting duct
c. The kidney develops sequentially from the somites. Under each one
of the somites is a nephrotome; this is where the main functional unit
of the kidney, the nephron, develops from.
d. Originally the pronephros served in embryo and the opisthonephros
(more adults) in the adult
e. Nitrogenous waste was probably originally eliminated as ammonia
(highly soluble, diffuses into water across the gills)
Reproductive System: functions in production and release of gametes, and
may support developing embryos
a. Gonads are multicellular (female = ovaries; male = testes)
b. Ancestrally, gametes were released into the coelom (body cavity)
then through pores near the cloaca (using muscle contraction)
c. Fertilization and development were originally external
Endocrine System: function in communication and coordination
a. Information transfer is slow, general, and long-lasting through
chemical signals (hormones and pheromones)
b. Includes endocrine (no ducts) and exocrine glands (ducts)
c. Originally only the pituitary
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d.
Pineal (coordinates daily and seasonal rhythms) and thyroid (controls
metabolism and homeostasis) plus scattered specialized cells
10. Nervous system: functions in obtaining information from the environment and
coordinating body activities
a. Information is transferred by electrical signals and is rapid, specific,
and short lasting
b. The basic units are neurons which includes three types
i. Sensory (receptor) – pick up information from
environment
ii. Motor (effector) – transmit information to muscles/nerves
iii. Interneurons – transport b/w motor and sensory
c. Two major components
i. Central nervous system (info, processing)
ii. Peripheral nervous system (cranial and spinal nerves),
including motor (ventral) and sensory (dorsal) roots. Which in
turn is made up of
1. Somatic system (body wall and appendages)
2. Autonomic system which includes
a. Sympathetic system (“fight or flight”): reacting to
environment, speeds up heart, increases blood
flow to heart, etc; react to stress
b. Parasympathetic (rest & digest): in control when
not reacting to environment; maintain while body
at rest
d. The brain includes basic sections
i. Telencephalon including olfactory lobes and bulbs
(olfaction; receives chemical info from mouth/nose), cerebrum
(voluntary movement, learned behaviour and corpus striatum
(instincts?)
ii. Diencephalon including
the thalamus (sensory relay between parts of brain
coordinating info), hypothalamus (visceral integration;
coordinates diff parts of body), pituitary (coordinating body
activities), pineal
Mesencephalon - originally optic lobes
iii. Metencephalon including the cerebellum
(hearing/balance/orientation/motor coordination), and pons (coordination of cerebrum and cerebellum)
iv. Mylencephalon comprising the medulla oblongata (reflex
centres for basic functions)
e. Nervous system also includes receptors for taste (chemoreceptors),
smell (chemo), touch (mechanoreceptors), temp (thermoreceptors) as
well as multicellular sense organs for
i. Photoreception, including colour and UV vision (not in
humans but can help animals find food and is use in mating
displays)
ii. Eye including a cornea, lens, iris, and retina
 lens: produce clear picture on retina
 pupil: regulates intensity of light entering eye
 retina: sheet of photoreceptors and neurons lining back of eye
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iris: ctrls. diameter and size of pupil
iii. Detection of orientation, motion, and infrasound vibrations
(inner ear) via hair cells (cells with special cilia that detect
motion in the extracellular fluid).
1. 3 semi-circular canals:
2. three sacs: (I believe that they are separate from the
canals) utriculus (joint where the canals come together),
sacculus (involved in detecting orientation in space, esp.
vertical - head movement puts P on otoliths, moves
gelatin, moves cilia which cause E signal to brain),
utricle (more horizontal movement) lagena (detects low
frequency sound, evolves into cochlea in amniotes)
3. Origin of Jaws
https://www.youtube.com/watch?v=whhWWL1AKbg
The Jawless Fishes: (Agnathans)
-do any living vertebrates exhibit just the basic body plant?
1)Infraphylum: Hyperotreti, Class: Myxini
-includes 20 extant species of deep-sea scavengers (Hagfishes)
-Have most of the basic characteristics of invertebrates-except vertebrae - whip-like
motion with tails (like sea snakes) for locomotion
-in addition, hagfishes have several “derived”(specialized) traits:
a)mucous glands and thread cells
b)degenerate eyes-protein secretion from thread cells and mucous production=avoid
predation
c)”teeth”on tongue
d)unique feeding-most have degenerates eyes=lost as vestigial feature since eyes
are not useful in deep sea
no jaws, vertebrae - tie knot in body, slide off to close mouth!
-TEETH-not true on tongue to help scrape off scales when feeding etc.
2)Infraphylum Vertebrate:
-class Petromyzontida- larvae resemble what early chordates would have looked like
-look very different from adults (Ammocoetes)-ugly af ← LOL, hahahahah
-includes >40 species of parasitic fishes (lampreys)- petro=rock,, myzo=sucking
-demonstrates the basic vertebrate design as larvae (“Ammoceotes)
-but as adults, they have many specializations ex:
-digestive system specialized for parasitism (no stomach, saliv. glands)
-can cling to side of fish via suction (check out image of mouth on google)
- drink fluids/blood - have anticoagulents to keep blood flowing after sucking
tidal ventilation - when attached to fish water can come back in through gill
pores back and forth to keep attached*
can sense body temperature drops and bite swimmers when they get tired
-tidal ventilation several species are pests of commercial and sport fisheries
Whats missing?
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- jaws in mouth
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- paired appendages
countercurrent exchange
stomach, saliv glands
The origin of Jaws:
- most vertebrates have jaws and paired appendages: when did these evolve?
Gnathostomes:
-probably originated in the mid Ordovician (480 mya)
-underwent a second duplication of the Hox genes! now 4x genes
-possess numerous derived characteristics (specializations compared to agnathans:
1-skeletal system
-jaws, derived from the first two pharyngeal arches
-teeth (true teeth)
-enamel- hardest known organic substance
-two pairs of appendages (pectoral, pelvic), probably derived from skin folds
-pectoral fins developed into arms in humans
-pelvic fins dev. into legs
-paired appendages allow for greater stability and agility
- more adept swimmers than agnathans
2-Respiration system:
-gills with counter-current exchange
-gill arch --> primary lamella --> secondary lamella
-Counter current exchange
- blood flowing in opposite direction than water to accommodate for changing
salinities, etc for efficient transport of oxygen
constant gradient = more efficient, 90% opp to 50%
-capillary beds in secondary lamella
-hypothetical - if blood and water flowed in same direction, not as efficient*
3-Reproductive system:
-NEW - ducts for gametes, not just into coeloem, out cloaca. gametes excreted via
the archinephric duct(sperm) or oviduct (eggs)
-external fertilization
4-Nervous system
-myleniated axons
→ myelin insulates the axons, if they are not insulated electrons are lost so
you dont get an efficient transfer of electrical impulse AND axons are going to start
interfering with eachother (signals get confused), allows many to run parallel
-lateral line (canal containing groups of hair cells )for sensing motion in water
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-without myelin sheath on axons - lose conductance/transmittance of charge
through neurons (saltatory conduction)
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-"hair cells" = cilia
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- small changes in pressure detected along the cilia (via openings/pores) sends info to the brain to detect motion/environment (check diagram)
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-pores also allow for the detection of electrical fields that other organisms
transmit (water conducts electricity better than air, so fields more prominent in
aquatic env) - these can be used for predation, courtship, etc
SHARKSzzz
-may also detect electrical fields
DO any living species exhibit just the basic gnathostome design?
-NO gnathostomes diversified during the Ordovician (450 mya) and include 2 derived
lineages:
1-class Chondrichthyes (cartilaginous fishes)
2-Bony fishes and tetrapods
A) Class Chondrichthyes:
-whats special about the Chondrichthyes?
-living chronrichthyans have several distinctive characteristics:
1-placoid scales
2-teeth replaced continously
-placoid scales:
- streamlined and directional scales
- smooth in one direction, while rough in the other (smooth in direction of motion)
-skelton maybe calcified, but not ossified; fins supported by keratinized rods - can’t
flap, used for stability and steering
-no true bone cells - cartilage to keep to them buoyant and more agile in the water
-ventral mouth; intestine with spiral valve; liver often oil-filled for buoyance to
compensate for lack of swim bladder ex) think of how oil floats on water → increased
oil for buyoancy
-osmoregulation via urea
-eggs generally develop in a protein sac (oviparous) but some species are
ovoviviparous (female retain eggs during development) or viviparous (developing
young are supported by a placenta) ;internal fertilization via pelvic claspers
-give birth to live young (oviparous)
-well –developed electroreception; reflective layer in retina enables in dim light’
strong olfactory sensitivity
Is there much variation within Chondrichthyes?
-chondrichthyes underwent three major radiations;two major groups remain including
900 species:
1-Holocephali
-chimeras,ratfishes
-feed on crustaceans
-specialized to feed on crustaceans
-upper jaw is fused to the cranium
-teeth modified into grinding plates
-one gill slit
-crush molluscs much more efficiently than a shark could
-gill slit reduces the amount of SILT being let into the gills
2-Elasmobranchii
-modern sharks, rays, skates
-active predators and planktivores
-jaw-opening mechanism enables jaw protrusion and suction;stiff fins and
heterocercal tail provide lift (different sized lobes in tail); multiple gill slits
-active predators
-specializations for being active predators1)jaw protrusion(creates suction when feeding)-when they open upper jaw,
causes lower jaw to go out (mouth cavity becomes bigger and suction
occurs-efficient feeders
2)electroreceptors in snout- so by drawing teeth away it protects these
receptors
3) they have stiff fins-they don’t use them for propulsion-just the tail is used
for propulsion. Stiff ins-for stability in water.
4)heterocercal tail-upper lobe of tail is larger than lower lobe-created upward
force of body which keeps them level.Prevents them from sinking.
5)multiple gill slits-characteristics of the group
4. Osteichthyes – Bony Fishes
Bony ridge scales – support the fins (rods support fins in chondrichthyes), provides
protection and flexibility. , laid down in concentric rings (can age fish)
Osteichytes have 2 bony scales that curl around each other and can use paired fins for
propulsion through water in many directions, unlike sharks
· Mostly predatory
· Skull + skeleton (inc. shoulder girdle) composed mainly of dermal bone
· Teeth fused to hinged jaws (hard to lose/irreplaceable vs. easily lost in sharks)
· Gill slits covered by a bony operculum
o Gill rakers – hard serrated structures for protection of gills and prevent
passage of coarse material, only allow passage of H2O
· Swim/gas bladder for buoyancy
o Gas added during dive to deep water, density increases (incr.
buoyancy)
o Gas removed in ascent to shallow/surface waters, density decreases
(decr. Buoyancy) (move up)
· Coiled intestine and cecum pouches (digest plant material)
· Streamlined body shape + mucoid secretions + vertical caudal fin = low turbulence
Ceca: the home for bacteria which digest plant material and aid in the breakdown in
cellulose, which releases sugars and provides nutrition
Actinopterygii
· 1/3 of all vertebrate species (ray-finned fishes) – modern fish
· Bichirs, strugeons, bowfin (primitive forms with heavy scales+ simple jaws)
· Teleosts – tangs, pikes, eels, tunas, perch, salmon, cod, sunfish, bass, haddock, etc
o Extremely diverse group – variety of habitats, scales/epidermis, body
size/shape, feeding habits + migration habits
o Protrusible upper jaw: ligaments attaching lower jaw pull upper jaw
away from space for enlargement/suction - vs. bone attachement in
sharks
o Pharyngeal jaw: jaws inside throat with teeth – mouth opening pulls
inner jaws to the mouth, two sets or teeth (prey capture and holding?)
(i.e moray eel)
o Homocercal tail: upper/lower lobes of caudal fin are same size,
available for steering/maneuverability
Migration habits vary in Teleosts
anadromous: ex. Tuna, spawn in freshwater, mature in ocean
catadromous: ex. Eel, spawn in ocean, mature in fresh water
Sarcopterygii (lobe-finned fishes)
· Lungfishes and coelacanths
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o Locomotion of African lungfish (Protopterus annectens) more similar to
tetrapods (first four limbed vertebrates) than aquatic fishes (like croc
walk – pelvic vs. pectoral fins and tail – alternating movements, fins
used to lift body from surface)
Heavy scales for protection
Gave rise to the tetrapods (mid-Devonian)
Adaptations arose from living in aquatic environments with poor/low oxygen content
in the water or the water was ephemeral (temporary)
o Fleshy fins with fin rays that form a “feather”
o Lungs and double circulation + 3 chambered heart
o Aestivate (go dormant – lower metabolic rate) during droughts
5. Origin of Tetrapods and Amphibians
The Origin of Tetrapods
 Land vertebrates (tetrapods) probably originated in the mid Devonian, ~360
mya, from sarcopterygian-like ancestors (lobe-finned bony fish)
 Advantage of land: Could get get away from aquatic predators
Invasion of the Land
Many morphological and physiological changes:
Skeletal System
 axial skeleton (support weight of body)
 limbs for support
 Lighter skull and an atlas (move head up and down)
Digestive System
 muscular tongue
 salivary glands (to lubricate prey to be swallowed)
 large intestine (colon) to conserve water by reabsorbing water from food
Excretory System
 N wastes excreted as urea
 Bladder: holds urea and water
Nervous System
 eyelids and tear ducts; keeps eyes lubricated and protected, fishes don’t
carry these
 sensitive hearing
 middle ear (improves hearing because sound doesn’t travel as well in air
compared to water) middle ear = tympanum, columella and oval window
 The middle ear transmits the motion (by tympanum) to the inner ear
 Tympanum: ear drum
 Columella: a middle ear bone that magnifies motion from the typanum to the
oval window
 Oval window connect middle ear and inner ear
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AMPHIBIA
Not just “primitive tetrapods”, very specialized
Integument: important for protection, osmoregulation, temperature regulation, and
cutaneous respiration
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Many mucous and granular glands (poison = primary defence) to keep integument
moist
o Thus habitat areas close to water bodies to maintain moisture levels
Granular gland: poison gland
No scales
Highly vascularized
· Secondarily lost fins – to prevent interference of temp/osmoregulation
Digestive System
· Carnivorous diet + protrusible tongue (attaches at anterior part of jaw and “flips” out
to capture prey with sticky secretions)
Respiratory System
o External gills in aquatic forms (secondarily evolved from ectoderm)
o Buccal-pump (+ve pressure pump): lowering the buccal cavity and use
buccal muscles (uses throat muscles) to force air into lungs (no
diaphragm)
o Cutaneous respiration via integument or vascularized mouth
o i.e Hellbender secondarily lost lungs and solely breathe through skin
 Lost lungs (because they don’t need to control their buoyancy)
· Circulation
o 3 chambered heart + spiral valve to enable differential control of blood
flow to different body regions (check notebook for diagram)
In water: constricts pulmonary artery to lungs and therefore goes to skin
Four chamber heart doesn’t have this capability to use both air and water
for oxygen
· Reproductive System
o Most indirect development (metamorphosis with larval stage included,
directed by thyroid and pituitary), some have direct development (no
larval stage) and some retain juvenile characteristics in adult form
(paedomorphic)
o Under control of pituitary + thyroid hormones (Thyroid stimulating
hormone released in some organisms to promote limb growth and
other changes in metamorphosis)
· Nervous System
o more developed cerebrum/midbrain than fishes (more sensory
processing and control)
o special sensory patch in inner ear detects high frequency sounds
transmitted by columella
o pectoral girdle is connected to the oval window to detect low frequency
sounds
o thus detect both low and high frequencies, but not great at detecting the
frequencies in the mid-range
6. Origin of Amniotes
Amphibian diversity: ~4200 species of amphibians
1. Gymnophiona
a. Caecilians
b. Worm-like, burrowing, sensory tentacles on head to help them detect
prey, and maybe reduers and newts- ~1600 species, more common than
ceacilians but still not extremely common.09
b. 4 legs of equal-ish length, mostly as props, out to side vs. vertical in
mammals ,
c. tail present throughout life- wiggle their bodies in a fishy-like manor
d. internal fertilization via a spermatophore- protein capsule containing
spermatozoa. Essentially they hump each other for a little bit and then the
male puts his spermatophore down on the grounced eyes, maybe
ovoviviparous- give birth to live young.
c. Sometimes people think they are “naked snakes” or “giant worms” but
aren’t closely related to either! No scales, have annular folds around their
bodies like a worm would - moves like worm not snake
d. lost their legs through evolution. Specialized group for burrowing
underground.
2. Order Caudata
a. Salamandd and the female picks it up in her cloaca as she walks over it.
LAWLS.
e. elaborate courtship involving pheromones- make noise as well.
f. many paedomorphic species (the development of sexual maturity in the
larval body
form
g. morphology most like the original amphibians probably.
3. Order Anura (~3600 species—still only 1/6 of the diversity seen in boney fishes
though)
a. frogs and toads
b. specialized jumpers with long hind legs, fused tail bones, fused pelvis,
short body, compact and rigid so their jumping can be efficient and accurate.
c. Fused bones: the tibiofibula (lower leg bone, fused tibia and fibula) and
radioulna (lower arm bone- fused radius and ulna) (humerus and femur bones
also specialized in the frogs)
d. courtship involves frog song (ontario tree frogs- they change colours and
make calls from trees that sound like duck calls)
e. urostyle- ending of vertebral column- like where a tail would be attached,
but fused.
f. Bifocal vision- overlapping fields of vision give them good depth
perception
g. Herbivorous tadpole larvae
Reproduction on land- amphibians must lay their eggs in damp or wet places, but
reptiles, birds, and mammals do not. This is because of the evolution of the amniotic
egg in the amniotes.
o Amniotic (cleidoic) egg- free the reptiles from having to be tied to wet
environments.
o before, eggs would dissipate if they were removed from wet environment.
Needed water to maintain egg integrity.
Amniotic egg: contain yolk and albumin (white of the chicken egg), and 4
vascularized membranes:
th
1. yolk sac: transfers nutrients from the yolk to the embryo (nutrients layed
down in the ovary)
2. amnion: protects the embryo from dehydration and injury (essentially the
eggs own personal mobile pond)
3. allantois: serves as both lung and bladder. (endoderm derived, highly
vascularized. eventually will completely surround embryo. takes up the
nitrogenous waste, keeps it away from developing embryo. acts as a lung)
4. chorion: surrounds everything, aids in gas exchange. Contains and
protects everything- develops from the mesoderm.
o In the pic- blue things are derived from ectoderm, yellow derived from
endoderm
o As the membranes develop- pretty much everything grow down around the
yolk- yolk gets smaller.
o A leathery shell is then layed down by the mother, which supports the egg
and protects the embryo from dehydration and injury.
o In birds, the egg is secondarily calcified, but is secondarily lost in
mammals.
o The egg is what freed the mammals from their water requirement, and
allowed them to have a complete life cycle on land
Other amniote specializationso Scales formed from keratinization of the epidermis (not homologous to fish
scales- refer back to notes on chondrichthyes, fish scales derived from bone)
makes skin impermeable to air and water. Therefore can not use skin at all
for gas exchange.
o Tiny triangles on human skin- indication that we actually have scales.
o Outer cell layer is dead- epidermis (dead dermis)
o Keratinized nails or claws (amphibians don’t have any)
o Secondary palate- allows animals to breathe through their nose while still
eating and chewing.
o Second cervical vertebra modified into an axis- allows for side to side head
rotation- works in tandem with the atlas (atlas was the up and down)
o Lining of lungs folded into alveoli, which allows for more SA for gas
exchange.
o Trachea is supported by cartilaginous rings- enabling a negative pressure
pump ventilation system. Activation of rib cage muscles expanding draws air
in, and relaxation shunts air back out. Trachea remains rigid, open constantly
(not true for amphibians- have to actively open it up)
o Embryonic kidney of amniotes is the mesonephros
o Functional adult kidney is the metanephros- specialized for water
retention: has more nephrons, longer nephric tubules, and counter-current
exchange (to soak back up water that's been lost). Super efficient filtering of
water ~90% retention compared to maybe 50% retention.
o A cochlea- developed from the lagena, that increase the range that can be
heard. This has a strip of hair cells that shift and send sensory signals to the
brain. Precise detection of sound, long tube so lots of room for differential
signals to be deciphered from one another.
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raccoons love fish
star-nose mole eat worms, can swim and feed on fish, most neurologically sensitive
organ 100,000 neurons to sense vibrations of prey
beavers are industrious, often die from tree falling on them
Guest Lecture: Fish
Guest Lecture: Herpetofaunao Vomeronasal organ- aids in olfaction. Essentially
a lot of chemoreceptor cells inside the olfactory bulb. Helpful for land animals.
o in snakes: myth that they “smell” with their tongues- not true. They
pick up chemical particles with their tongues, can detect minute
differences by waving their tongues around, and then when they tuck
their tongue back into their mouth and the olfactory cells of the
vomeronasal organ sense scents and chemicals.
Commonalities between reptiles and birds:
o class Reptilia (~330-300 mya) is actually a paraphyletic grouping bc it
doesn’t include all the descendents of a single ancestor (AKA its not including
the aves) the birds, despite the fact that they descended from the same
ancestral species, are regarded as a separate class.
o birds really should be members of the reptiles! they are more closely
related to crocodiles than the turtles or lizards are to crocodiles.
o reptiles do NOT actually possess any defining characteristics that make
them distinct from the birds. They both possess all the characteristics of
amniotes.
Reasons why birds and reptiles should be in the SAME group:
o Scales: include a distinct tough type of keratin: B-keratin, same in birds
o Nitrogenous waste in the birds and reptiles is excreted as uric acid- like
extra concentrated urea- meant to conserve even more water. Looks like
white crystals- what you see next to bird poop in the summer. Takes very little
water to get rid of.
o Females have a shell gland or “uterus”—reproduction is usually oviparous.
Shell gland is where the leathery shell (reptiles) or the secondarily calcified
shell (birds) comes from.
7. Reptiles
4 orders - Testudines, Squamata, Sphenodontida, Crocodilia
- all diverged around Carboniferous (300 million yrs ago)
Testudines (turtles and tortoises)
- pretty much found everywhere - highly successful
- Shell: dermal (endoskeletal bone) overlaid by keratinized scutes
- cannot separate turtle from shell, ribs fused to shell
- appendages inside shell
- protective coat (great safety retreat), however cannot breathe whilst fully in
shell
- no teeth, have a secondarily developed beak like birds
- Respiration: requires labourious muscle contraction to breath
- no diaphragm, have modified muscles (serratus and pectoral) which move
the pectoral
girdle and posterior membrane to ‘squish’ the lungs and force in air
- limbs move with each breath pectoralis and ab. oblique pulls serratus and
post lim membrane down, squish viscera, allow lungs to expand. ab. transverse and
serratus pulls back up, expell air, viscera back up
-turtles breathing: https://www.youtube.com/watch?v=Z5NmKuqP0fU
Sphenodontida (Wedge toothed)
- highly conserved through time
- only few species exist today (2-3), once existed in various diverse forms
- GODZILLA??
pinneal eye: third eye in middle of forehead to detect day length
- 2 rows of upper teeth for increased grip when capturing insect prey
- Tuataras
- inhabit seabird colonies and feed of insects that are attracted to pooping birds
Squamata (3 suborders - lizards, amphisbeans, snakes)
- appx. 5700 spp, recently radiated (increased diversity today vs. before)
- most have 4 chambered heart
Lizards
- paraphyletic group - common ancestor of lizards also same as the common
ancestor of snakes and amphisbeans, however snakes/amph not a part of ‘lizard’
suborder
- inflexible jaw: upper jaw fused to cranium and lower jaw fused to muscles
- open and close like ours
- autotomous tail: some can lose their tail without losing blood as an escape strategy
from predation
- can regrow their tail but regrowth is not necessarily a proper tail (simple tail
regrown)
- may compromise survivability of the animal
- tail = storage of fats
- hemipenes - 2 penises (lol) but only one used while banging ;D← such funny,
much laugh, wow. Ok I just cracked up #threeyearsold #shamikufunny lols lols losl
OMG HEHEH
Amphisbeans
- appx 120 spp.
- can move fwd and backwards with equal ease, head and tail look the same (only
one head however)
- burrowers
- ring-like folds in skin
- no limbs mostly (no hind limbs fo shizzle and most times no forelimbs)
- movement via compression/stretching like an accordian, unlike slithering motion of
snake
I guess kind of similar to caecilians, but reptiles (keratin scales, uric acid, secondary
palate)
Snakes
- appx. 2900 spp.
- loss of legs occur multiple times independently in reptile history
- advantages: increased motility/hiding/predation
- no middle ear, use vibrations from ground - can detect direction of movement of
another animal by picking up super-sensitive vibrations (to find prey/escape
predation)
- no limbs/pectoral girdles, usually no pelvic girdles either
- asymmetrical internal symmetry due to long slender body type (only R lung)
- Digestion:
- kinetic (flexible skull)
- jaw can come apart (lower and upper not fused) and stretch along with skin
that lines with mouth to allow for swallowing of prey much larger than size of
head/mouth
- video???
- recurved teeth to grab prey and prevent from escaping
- titanoboa = largest snake that ever lived, proof of hotter earlier climates
Crocodilia
- appx 21 spp.
- ancient reptiles, virtually unchanged in 300 million yrs
- have beta-keratin scales and thick dermal plate armour
- four chambered heart although body adapted for marine/aquatic lifestyle
- highly capable swimmers and highly mobile (gallop like horse) on land
- https://www.youtube.com/watch?v=x0qRr6DwVTU
- don’t fuck with these guys
- warm blooded??????????????
- lays eggs (*oviparous?): females incubate eggs and display parental care with
young often following babies for months offering protection from predators
- highly intelligent: have well developed cerebral cortex DONT CALL THEM BIRD
BRAINS
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8. Ornithology
Origin of Birds
Birds evolved from dinosaurs around 125 million years ago. Paraphyletic with
reptiles and they share several features with reptiles and dinosaurs.
With Reptiles:
· Nitrogenous waste = uric acid
b-keratin scales (under feathers – look at talons)
4 chambered heart (crocodilians)
Oviparous reproduction
With Dinosaurs:
Diapsid skull structure
S-shaped neck and hollow bones and 3 toes
Furcula + flexible wrists
Use of head as an extra appendage
Calcified egg shell (strength)
Origin of feathers predated flight – baby therapods may have been feathered for
insulation purposes but lost them as they matured.
Sinosauropterix had protofeathers evolved for display or heat retention
Flight/wings may have evolved from jumping development from raptors
Archaeopterix mainly glided – not true flight
Wing development to free hindlegs as use as weapons/defense? (cockfighting)
Ornithology
Integumentary System - Feathers
· Important for flight, insulation, water proofing and communication
· Receive tactile information from environment
· Help distinguish species and for mating displays
· Epidermal derivatives that are thought to be specialized reptile scales (due to bkeratin content and similar but more complex development)
· Molted at least once a year (spring)
o Especially fancy coloured ones used for mating purposes to retain bold
colours
· Sole large oil gland – to produce oil layer on contour feathers (part of “preening”) no
other epidermal glands (no sweat, so no moisture in down)
1. Pennaceous Feathers
· Water proofing, contain thin layer of oil
o Contour feathers – flight feathers
· Contains long shaft and barbs – barbs have interlocking barbules coming
out of them forming a mesh-like pattern
o like Velcro-hook together to form a net for strength
· these are resealed during preening
2. Plumulaceous feathers
· Provide insulation(no interlocking barbules)
3. Filoplume feathers
· Few barbs but many nerve endings and serve as tactile receptors
Skeletal System
· Highly modified for flight
o No teeth to reduce weight
o Arms specialized as wings - inner (lift) and outer arm o Furcula
(wish bone) braces wings and shoulders for flight, acts as a spring
for flight stroke
o Pneumatic bones – hollow, supported
· Flexible neck – beak can be used as a secondary appendage
· Nasal turbinates help retain water/heat
· Hand bones fused, lumbar/tail bones fused for increased balance and
stability during flight
Muscular System
· Wing muscles concentrated below the body
o Massive pectoral muscles – 30% of entire body weight, muscles have
a high concentration of mitochondria and blood vessels
· FLIGHT = Lift + Propulsion
o Upper and lower arm and secondaries = lift (common to flying
squirrels, etc [inner wing])
o “Hand” and primaries = propulsion (rare – outer-wing driven: bats,
birds)
o Tail = lift, balance, steering
-inner wing provides the lift & outer wing (hand) provides the
propulsion
-tail provides lift, balance, steering and braking.
Digestive System
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Food processing done by the gut, teeth lost
Crop holds food prior to digestion – enables feeding of chicks
Stomach contains the proventriculus and gizzard:
o Muscular abrasive gizzard - where most of the mechanical breaking of
food occurs
o Proventriculus = glandular chamber for food storage
Circulatory System
4 chambered heart – two divided ventricles and two atria (same as ours)
Erythrocytes are biconcave
o Adaptations to accommodate for fast metabolism
Respiratory System
Efficient ‘2 cycle’ respiration involving the parabrochial lungs and air sacs
Air sacs allow for unidirectional air flow
o Also improve cooling + bouyancy
Enables counter current exchange
Air into primary air sacs via inhalation, exhalation into secondary air sacs and then
second exhalation out
o Cycles occur simultaneously – providing constant air flow and O2
supply (no problemo at high altitudes)
Syrinx enables calls/songs
Excretory system
Uric acid waste but no bladder
Metanephric kidney
Reproductive System
Same as reptilian reproduction with following exceptions
o Females only have left ovary and oviduct
o Gonads degenerate outside of breeding season (testes undergo 300x
size increase in season)
§ To minimize energy expenditure to maintain repro. structures
o Chick development ranges from altricial (helpless at hatching) to
precocial (independent at hatching)
o Many species have complex breeding behavior – mating displays, etc
Nervous System and Senses
Vision and hearing extremely important in birds (large forebrain)
o Eyes can consist of 15% of body weight – high visual aquity
o High density of rods and cones,
o Eyes contain a pecten (reduction of blood vessels in front of retina to
sharpen image – hawks), may protect from UV rays
Hearing:
o Tympanum: oval window area ratio is large,high magnification
o Density of hair cells in cochlea is high
o Extra muscle can disengage the columella, protect from loud sounds
Olfactory lobes, cerebrum not as well developed (except turkey vultures)
Many species are capable of detecting a magnetic field
>9100 spp. In 27 – 29 orders
most arose within last 65 M.a
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o due to opening of niches post dino death (Massive terror birds of the
Eocene!)
Ratites (5 living orders)
Ostriches (Africa), kiwis (NZ), cassowary, emu (Australia) rhea (S. America)
Long ass legs as adaptation for running (cursorial omnivores)
Reduced wings – no keel (keel = attachment point for wings)
Kiwis trying to evolve into mammals
o Hair-like feathers
o Increased olfaction
o Run probing the ground like mammals
o POSERS
Sphenisciformes
Penguins
Pursuit divers
Scale like feathers, high body fat content
Solid bones – to allow them to have some density for diving purposes
Adaptations for swimming:
o Wings modified into paddles, webbed feet, legs far back as a rudder
Piscivores (fish eating), narrow serrated beak to increase traction on fish
Procellariiformes
Albatrosses, petrels, fulmars
Pelagic: wings adapted for soaring with a special wing-lock mechanism
o Long narrow inner wing, no wing slots
o Fly for days/weeks without having to come down
Tubular nostrils with airstream pockets
Half of their brain can sleep at a time
Piscivores – narrow serrated beak
Apodiformes
Hummingbirds and swifts
Aerial nectivores and insectivores:
o Small body
o Specialized tongue
o Wings adapted for hovering (long wingtips and short stout humerous)
o Wings beat multiple times per second
Psittaciformes
Parrots
Arboreal fructivores
Deep hooked beak, upper mandible hinged to skull
Feet modified for climbing
Short, rounded wings and highly intelligent
o Can imitate sounds
Passeriformes - largest order
Sparrows, jays, wrens, swallows, warblers and chickadees
Feet adapted to perching – locking mechanism, when legs are bent at a certain
angle, the talons lock (birds can sleep without fear of falling from wires or branches)
Strigiformes
Owls
Nocturnal birds of prey
o Large, forward directed eyes
o Facial disk (concentrate sound waves on ear)
o Large external ear openings that may be assymetrical – acute hearing
o Soft plumage
o Talons and hooked beak (diet = mice, small rodents, etc)t
9. Mammals
Origin of Mammals
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mammals diverged from reptiles and birds ~330 mya - so they evolved 1st!!
filled empty dinosaur niches
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mammal characteristics evolved gradually over a period of ~200 million years
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originally mammals were probably small, active, nocturnal insectivores
-they evolved during the time of the dinosaurs, so they found a niche being small
and being active at night
Common Characteristics of Mammals
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Integumentary System
-Hair
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whiskers – sensory structures – important for detecting touch
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fur – insulation
Guard hair – (like contour feathers), thick, layer of oil on them, repel water
Undercoat – (like down feathers), small and fluffy, hold heat against the body
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Smooth muscles (arrector pili ) raise hair for insulation when it’s cold or for
communication, to make the animal look bigger when afraid or angry, that is what
goosebumps are
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Fur is shed once or twice a year – to change colour to camouflage, or for
reproduction
Mammal skin also contains many glands (oil, sweat and scent glands) and fat
deposits including brown fat to generate heat
Mammary Glands: epidermal glands that enable lactation – mammary glands
secrete a solution of carbohydrates (lactose) and lipids to nourish young
Skeletal System
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Mammals have unique teeth, they have up to four different types of teeth that
are specialized for eating certain kinds of food, they have incisors, canines,
premolars and molars, incisors are for biting, canines are for tearing, molars are
for chewing
è Heterodont Dentition
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Teeth have deep roots that are cemented into the jaw
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Teeth meet precisely
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two sets of teeth – deciduous (baby) teeth and permanent (adult) teeth
Nasal Turbinates
warm and moisten inspired air
salvage moisture from expired air
provide surface area for olfactory receptors
-Mammals have a dorsoventrally flexible spine, vertical appendages, and a reduced
tail, enabling a bounding gait – allows for rapid movement
-tail is involved in balance and steering
-7 neck vertebrae – cervical vertebrae
Muscular System
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-complex facial muscles enabling suckling, chewing, facial expressions and
communicaton
-Diaphram – enables ventilation of the lungs, diaphragm contracts and the ribs
expands which decreases the pressure and makes air flow into the lungs – negative
pressure system
Circulatory System
-4 chambered heart, oxygen rich blood and oxygen poor blood kept separately
-this four chambered heart evolved separately in birds and mammals
-systemic and pulmonary circuits = separate
Respiratory System
-alveoli are well developed
Nervous and Sensory Systems
olfactory lobes are highly developed – likely because early mammals were nocturnal
and smell is important for nocturnal animals
optic lobes are reduced
cerebral cortex is highly developed and convoluted - allows for the cell bodies to be
on the outside and axons to be on the inside for rapid communication between
neurons (balloon analogy)
the cerebellum is highly developed – complex behaviour and complex movement
Vision –
-the midbrain (mesencephalon) was the original center for coordinating reflex
responses to visual input
- early mammals were nocturnal so they don’t have many cones and they have lots
of rods, visual acuity is low, but visual sensitivity is high which is important to detect
movement in the dark – colour vision has been almost completely lost in most
mammals except it has secondarily evolved in primates and squirrels and a few
other mammals
Hearing - auditory sensitivity = HIGH because sound is very useful at night–
elongated cochlea – coiled up – lots of surface area
-ear flap (pinna) – concentrates sound waves onto tympanum, helps animals locate
sounds, most animals are able to move their ears
-3 ear ossicles
Olfaction – olfaction sensitivity = high
Mammalian Diversity
-~5,400 species, 3 main infraclasses, ~27 orders
1. Infraclass Ornithodelphia
-ancient lineage in mammals, diverged 200 mya
-used to be really diverse but now there’s only 3 species left
-platypus, spiny anteaters
-OVIPAROUS –eggs incubated in a burrow or pouch on females body
àtherefore live birth is not a defining characteristic of mammals because some lay
eggs
-no nipples but they do lactate, they secrete milk onto fur and their babies lick it off
-adults are toothless
-beak of duck, feet and tail of beaver, body of rat
-beak-like snout with electroreceptors
2. Infraclass Metatheria
-Marsupials
-found mostly in Australia – unique reproduction
-opposums, koalas, wallabies, kangaroos
-mammary glands with NIPPLES
-VIVIPAROUS
-embryos nourished via a yolk sac placenta – association of the embryonic
membranes and the endometrium (uterine lining) ( chorion and yolk sac)
-the young are born at a very immature state and they complete development in a
MARSUPIUM attached to a nipple –primitive placenta – good for Australia though –
advantageous – dry
-2 to 3 young may be supported at the same time
-one embryo in uterus
-one permanently in marsupium
-one joey coming in and out of the marsupium and feeding on a different nipple
3. Infraclass Eutheria
-placentals
-VIVIPAROUS
-prolonged gestation chorioallantoic placenta
-blood from placenta goes in one direction and blood from mom goes in the other
direction, they never meet – efficient (allows diff. blood types)
-mammary glands with nipples
-radiated into ~20 orders around 65 mya – when dinosaurs when extinct
1. Order Insectivora
-hedgehogs, shrews, moles
-small, highly active, nocturnal insectivores
-limbs specialized for digging (short and fat,strong), eyes reduced, sometimes
venomous but can’t hurt humans
2. Order Rodentia
-rats, mice, capybara, squirrels, agouti, porcupines, beavers, muskrats, chinchillas
~2000 species
-largest order
-mostly herbaceous gnawers
-teeth grow continuously
-enamel only on anterior surfaces of incisors, only dentine on back, dentine is
weaker, and it chizzles away when they chew leaving a sharp edge
-jaws specialized for grinding –molars farther back, when they open and close their
jaws, molars come together at the same time, jaw joins higher than molars
Hindgut fermentation à Cecum – between small intestine and large intestine –
fermentation to get glucose out of cellulose – get energy
Cophropagic –eat their feces, a lot of glucose gets passed out in feces (doesn’t get
absorbed in small int) eat it again, they get all of the glucose out
3. Order Artiodactyla
-swine, hippos, deer, giraffe, sheep, goats, antelope, cattle
-legs specialized for running (long and thin)
-ungulates with even numbers of toes
-long face with lateral vision – eyes on the side of their faces, so they can see mostly
around them, so they can see prey
-may have horns or antlers
Foregut Fermenters
Cows = cud chewers
4 stomachs
-bacteria starts to break up cellulose in first two stomachs, then burp it up and
reswallow it
-bactera break down food so they can enjoy the nurtients
Abomasum = true stomach where gastric juices are secreted
4. Order Cetacea
-porpoises, whales
-hairless – secondarily lost their hair
-thick sub-cutaneous fat – convergent with penguins
-tail modified into flukes, tail is main propulsion
-pelvic limbs reduced
-pectoral limbs modified into flippers
-nostrils located dorsall
-teeth homodont or absent
-highly intelligent and highly social
5. Order Carnivora
-dogs, bears, raccoons, weasels, hyenas, cats, sea lions, walruses,
-not all carnivores are in the order Carnivora and not all of the animals in the order
Carnivora are carnivores
-usually carnivorous
-canines usually large
-molars modified into slicing apparatus, jaws make scissor like action – molars come
together toward the back and then to the front, molars come together sideways to
provide slicing mechanism
-broad lower legs with claws
6. Order Chiroptera
-BATS ~1000 species
-limbs modified for active flight
-they have a keel like birds do that flight muscles attach to
-long bones are almost hollow – not filled with heavy calcium
-many use echolocation - frequency gets quicker as they narrow in on the moth
àmoths have evolved mechanisms to confuse bats – they make their own sounds,
confuses bat so he misses it
7. Order Primata
-lemurs, lorises, tarsiers, monkeys, apes, humans
-mostly arboreal herbivores and fructivores – eat leaves and fruit in the trees
-opposable first digits – lets them grasp onto things like branches
-a lot also have opposable big toes
-flexible shoulders and elbows
-reduced snout – smell isn’t that important
-usually bifocal – eyes on front of head – depth perception to swing through braches
-colour vision secondarily gained – helps finding fruit in trees
-large brain: social, learn a lot, remember things
10. In conclusion
Guest Lecture: Birds
Guest Lecture: Mammals
Biol 202 Guest Lecture- Dale
Mammals
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tranquilize moose and watch how they react with parasites
how man mammal species in Ontario?
-excluding humans & domestic
-85
-4 wild mammals were introduced by humans
· European settlement, shipping
· Norway rats, black rats, house mice, European hare
· wild boar very aggressive, will attack, good smell, large tusks, expected to move into
St.Lawrence lowlands within next few years
· 4) Elk- collaborative effort to re-introduce into Ontario, will be north of Kingston soon
· most diverse group within the rodents, bats
· white-nose fungus is wiping out bats from Europe, N.American bats do not have the
European resistance
· SU= species unknown
· THR= threatened
· SC= species of concern
· END= endangered
· DNA validated cougar sightings has mexican origin= escapes
· possibility male cougar will meet a female and start a founder population
· latitude plays important role b/c influences climate and energy cycling
· great lakes support species that wouldn't be found further north
· trophic status- herbivores are more diverse, predators are less diverse
· regrowth of forest base in Kingston region
· cattle will align themselves in one direction to not be harmed by static
· ecozones= large, broad zones
· canadian shield- exposed bedrock, mixed forest (pines, wetlands)
· great lakes/st lawrence - deciduous , maple, ash
· AA-algonquin looking at supporting forest base from algonquin to new york, the 401
cuts down the middle of it
· wildlife corridor in bamf allows for the movement of animals
· urban wildlife-raccoons, skunks, coyotes
· deer have split, cloven hoof (artiodactylidae)
· get agressive in late October, mating season
· population extending as farms are abandoned, forests regenerating
· brain worm cause blind staggers affects moose
· white tailed deer very common eastern America, good game species, want to
promote
· not too sensitive to human presence
· horns are permanent and are connected to the skull- annular rings
· antlers fall off and are regrown each year, the calcium in antlers is reflective of the
availability of the food
· velvet= nourishing epidermis falls off before the antlers are shed
· carnivora= meat eaters ~26 species
· grey wolf common throughout Canada, mostly further north
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eastern wolf hybridized version perhaps of grey wolf and coyote, determined to be its
own species
Kingston people claim to see wolves, will actually be coyotes
eastern coyote has a lot of wolf genes gives it more size and bulk
coyotes eating domestic sheep, cats, dogs
some risk that they will become more aggressive
red fox found throughout, come out at late evening, early morning
foxes leap into deep snow to catch a mouse that they heard
bob cat found in boreal shield, occasionaly viewing in Ontario very shy and reclusive
animals
eastern cougar here before European settlers
black bears attracted to garbage- apple scented bounce
badger endagered
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fisher prey on grouse, porcupines, will scavenge on dead horses