Unit 3 Lecture Notes (in part)

Note: These notes are incomplete. They do not include all lecture material presented
and also include quite a bit I did not cover. Still, I think they could help you study
for the final. Use a fixed-space font (e.g., Monaco on a Mac) for correctly lining up the 
classifications below.

Echinoderms
<p>
<p>
Echinoderm Features (brief outline):
<p>

<p>
symmetry: think 5 except in larvae/fossils
<p>

<p>
skeleton: endo/collagen
<p>

<p>
water vascular system: uniquely echinoderm
<p>

<p>
nerves: no brain
<p>

<p>
respiration: extensions of coelom
<p>

<p>
fat storage: pyloric ceca
<p>

<p>
larvae: pluteus vs. bipinnaria
<p>

<p>
Echinoderm Feature (more detailed)
<p>

<p>
symmetry
<p>
	larvae are bilateral
<p>
adults are pentamerous
<p>
	but see cladogram p. 468!
<p>
	1st deuterostomes were bilateral
<p>
	1st echinoderms were bilateral or trimerous
<p>
Living echinoderms all descendants of a 
<p>
pentamerous ancestor
<p>
<p>

<p>
skeleton
<p>
	endoskeleton of calcareous "stereom" ossicles
<p>
	bound together with flexible/stiff collagen
<p>
<p>
	
<p>
water vascular system (Figs. 24-3, 24-19)
<p>
	left hydrocoel in larva (Fig. 24-9)
<p>
	madreporite
<p>
	stone/ring/radial/lateral canals (see p. 453)
<p>
	tube feet - ampulla/sucker
<p>
	ambulacrum
<p>
<p>

<p>
nervous
<p>
	nerve net (epidermal nerve plexus)
<p>

<p>
respiration
<p>
	papula (skin gills of seastars), hemal system (?)
<p>
<p>

<p>
fat storage
<p>
	pyloric ceca (stores energy for gonads)
<p>
<p>


<p>
larva - see p. 458, 475 (similar to hemichordate larva)
<p>
	pluteus (urchins, brittlestars)
<p>
	bipinnaria -> brachiolaria (seastars)
<p>

<p>
Bilateria
<p>
	Protostomia 
<p>
		(molluscs, annelids, arthropods)
<p>
	Deuterostomia 
<p>
		(echinoderms, hemichordates, chordates)
<p>
<p>

<p>
Deuterostome features (see p. 450):
<p>

<p>
	- blastopore (usually) becomes the anus
<p>
		never becomes the mouth
<p>
<p>

<p>
	- coelom forms through enterocoely
<p>
		(budded off the archenteron - see p. 109)
<p>
<p>

<p>
	- three pairs of coelomic pouches in larva
<p>
		(compare hemichordate larvae - p. 475)
<p>
<p>

<p>
	- endomesoderm
<p>
		(mesoderm from gut through enterocoely)
<p>
<p>

<p>
	- skeleton from mesoderm
<p>
		(not from ectoderm as in protostomes)
<p>
<p>

<p>
	- radial cleavage
<p>

<p>
	- regulative (indeterminate) cleavage
<p>
		(4-cell stage cells still form "normal" larva)
<p>

Classification of Echinoderms
<p>
	(living groups only - see p. 467)
<p>
<FONT COLOR="green" FACE="Monaco"> 
<p>
Echinodermata
<p>
	Crinoidea (sea lilies and feather stars)
<p>
	Eleutherozoa
<p>
		-Asteroidea (sea stars, probably also sea daisies - see Fig. 24-27)
<p>
		-Ophiuroidea (brittle stars)
<p>
		-Echinoidea (sea urchins)
<p>
		-Holothuroidea (sea cucumbers)
<p>
</FONT>
<p>
Diversity:
<p>

<p>
	About   6,000 living species
<p>
	About 20,000 fossil species
<p>

<p>
	"Stereom" ossicles - characteristic crystalline structure/composition (high-magnesium)
<p>

<p>
	Paleontologists can easily identify fossils as echinoderm ossicles
<p>

<p>
	Early Echinoderms did not have radial  symmetry or (?) water vascular system
<p>

<p>
	"carpoids" sometimes considered "calcichordates" not echinoderms
<p>
		
Echinoderm Feeding:
<p>

<p>
	Seastars
<p>
		many are predators
<p>
		stomach can come out of body
<p>
		
<p>
	Urchins
<p>
		scrapers, drift kelp, etc.
<p>
		5 teeth form "Aristotle's Lantern"
<p>

<p>
	Brittlestars
<p>
		many catch food with tube feet
<p>
		others are omnivores (eat anything)
<p>
		5 jaws
<p>
		all lack an anus (secondary loss)
<p>

<p>
	Sea cucumbers
<p>
		suspension, deposit, or detritus feeders
<p>
		use tentacles - modified tube feet
<p>
		can spew guts - eviscerate
<p>

<p>
	Crinoids
<p>
		arms with pinnules
<p>
		tube feet on each pinnule catch food
<p>

<p>
Other features:
<p>

<p>
	pedicellariae - defense or surface cleaning
<p>
		(only in seastars and urchins)
<p>

<p>
	regeneration - widespread
<p>

<p>
<p>
-----------------------------
<p>

Chordate Classification Hand-out
<p>
 <p>
<FONT COLOR="blue" FACE="Monaco"> 
<p>

<p>
Deuterostomia
<p>
 - Echinodermata
<p>
 - Hemichordata
<p>
 -  - Enteropneusta
<p>
 -  - Pterobranchia
<p>
 - Chordata
<p>
 -  - Urochordata (tunicates)
<p>
 -  - Cephalochordata (lancelets)
<p>
 -  - Craniata (craniates)
<p>
 -  -  - Myxini (hagfish)
<p>
 -  -  - Vertebrata
<p>
<p>
</FONT>
<p>

<p>
Terms
<p>

<p>
gill slits
<p>
dorsal hollow nerve cord
<p>
acorn worms (enteropneusts), pterobranchs
<p>
notochord, postanal tail, endostyle, thyroxin
<p>
tunic, pharyngeal basket, larvacean, salp
<p>
lancelet, ammocoete larva (lampreys)
<p>
Pikaia
<p>

<p>
Outline:
<p>

<p>
I. Overview of Chordate Relationships
<p>
 - - Chordate Classification Handout
<p>
II. Chordate Synapomorphies
<p>
III. Urochordates (sea squirts)
<p>
IV. Cephalochordates (lancelets)
<p>
V. Craniates (hagfish + vertebrates)
<p>

<p>
<FONT COLOR="green" FACE="Monaco"> 
<p>
<p>
Osteichthyes (bony fishes)
<p>
 - ray-fins
<p>
 - fleshy-fins (muscles in lateral fins)
<p>
 -  - coelocanths
<p>
 -  - Choanata (have choana)
<p>
 -  -  - lungfish
<p>
 -  -  - Tetrapoda (have 4 limbs)
<p>
 -  -  -  - Amphibia
<p>
 -  -  -  -  - caecillians
<p>
 -  -  -  -  - Batrachia 
<p>
 -  -  -  -  -  - salamanders
<p>
 -  -  -  -  -  - frogs and toads
<p>
 -  -  -  - Amniota (have amniotic egg)
<p>
 -  -  -  -  - Reptilia (or Sauropsida)
<p>
 -  -  -  -  - Mammalia
<p>
<p>
</FONT>
<p>

<p>
Bony fishes - ray-fin and fleshy-fin clades
<p>

<p>
ray-fins include teleosts (most vertebrates, 96% of fishes)
<p>

<p>
fleshy-fins include coelocanths, lungfish, and tetrapods
<p>

<p>
Important fossil tetrapods
<p>
 - - Ichthyostega, Acanthostega
<p>

<p>
What are tetrapod features and how do they reflect life on land?
<p>

<p>
Describe 3 types of respiration in a salamander.
<p>

<p>
What is paedomorphosis? Example: the axolotl
<p>

<p>
Rayfins have swim bladder to maintain bouyancy (p. 516)
<p>

<p>
Two methods:
<p>

<p>
 - simple (trout): 
<p>
 -  - pneumatic duct connection to esophagus
<p>
 - 
<p>
 - elaborate (diverse teleosts):
<p>
 -  - gas in from blood: gas gland
<p>
 -  -  - network of blood capillaries ("rete mirabile")
<p>
 -  - gas removed from bladder: resorptive area
<p>
 -  -  - 
<p>
Gas gland is highly efficient:
<p>

<p>
 - Example: fish living at depth of 2400 m
<p>
 -  - tremendous oxygen pressure differential:
<p>

<p>
 -  -  - blood must be kept at sea surface pressure
<p>
 -  -  -  (0.2 atmosphere)
<p>
 -  - 
<p>
 -  -  - swim bladder must be kept inflated
<p>
 -  -  - (> 240 atmospheres)
<p>

<p>
How does gas gland work?
<p>

<p>
 -  - secretes lactic acid into blood
<p>

<p>
 -  - forces localized release of oxygen from hemoglobin
<p>

<p>
 -  - oxygen diffuses into swim bladder
<p>

<p>
 -  - deep-sea fish have longer rete capillaries
<p>

<p>
More on how a fish works
<p>

<p>
Respiration:
<p>

<p>
 -  - gills use countercurrent exchange
<p>

<p>
 -  -  - blood flows opposite direction
<p>
 -  -  - to water pumped in from mouth
<p>

<p>
 -  - active fishes use ram ventilation
<p>

<p>
 -  -  - continuous swimming forces water in
<p>

<p>
 -  - diverse fish can gulp air
<p>

<p>
Osmoregulation:
<p>

<p>
Freshwater fishes
<p>

<p>
 -  - blood is about 0.25 M
<p>
 -  - freshwater is  0.003 M
<p>

<p>
 -  - they are hyperosmotic regulators
<p>

<p>
 -  -  - use kidney to pump out excess water
<p>
 -  -  - kidney has large "glomerulus"
<p>
 -  -  - also absorb salt with special gill cells
<p>

<p>
Saltwater fishes
<p>

<p>
 -  - blood is about 0.35 M
<p>
 -  - seawater is  1 M
<p>

<p>
 -  - they are hypoosmotic regulators
<p>

<p>
 -  -  - kidney excretes salts
<p>
 -  -  - intestine excrete salty feces
<p>
 -  -  - secrete salt with special gill cells
<p>
-----------------------------

<p>
Chordates: Early tetrapods
<p>
<p>
<FONT COLOR="green" FACE="Monaco"> 
<p>

<p>
Osteichthyes (bony fishes)
<p>
 - ray-fins
<p>
 - fleshy-fins (muscles in lateral fins)
<p>
 -  - coelocanths
<p>
 -  - Choanata (have choana)
<p>
 -  -  - lungfish
<p>
 -  -  - Tetrapoda (have 4 limbs)
<p>
 -  -  -  - Amphibia
<p>
 -  -  -  -  - caecillians
<p>
 -  -  -  -  - Batrachia 
<p>
 -  -  -  -  -  - salamanders
<p>
 -  -  -  -  -  - frogs and toads
<p>
 -  -  -  - Amniota (have amniotic egg)
<p>
 -  -  -  -  - Reptilia (or Sauropsida)
<p>
 -  -  -  -  - Mammalia
<p>
<p>
</FONT>
<p>

<p>
 Bony fishes - ray-fin and lobe-fin clades
<p>

<p>
ray-fins include teleosts (most vertebrates, 96% of fishes)
<p>

<p>
lobe-fins include coelocanths, lungfish, and tetrapods
<p>

<p>
Important fossil tetrapods
<p>
 - - Ichthyostega, Acanthostega
<p>

<p>
What are tetrapod features and how do they reflect life on land?
<p>

<p>
Describe 3 types of respiration in a salamander.
<p>

<p>
What is paedomorphosis? Example: the axolotl
<p>

<p>
 Rayfins have swim bladder to maintain bouyancy (p. 516)
<p>

<p>
Two methods:
<p>

<p>
 - simple (trout): 
<p>
 -  - pneumatic duct connection to esophagus
<p>
 - 
<p>
 - elaborate (diverse teleosts):
<p>
 -  - gas in from blood: gas gland
<p>
 -  -  - network of blood capillaries ("rete mirabile")
<p>
 -  - gas removed from bladder: resorptive area
<p>
 -  -  - 
<p>
Gas gland is highly efficient:
<p>

<p>
 - Example: fish living at depth of 2400 m
<p>
 -  - tremendous oxygen pressure differential:
<p>

<p>
 -  -  - blood must be kept at sea surface pressure
<p>
 -  -  -  (0.2 atmosphere)
<p>
 -  - 
<p>
 -  -  - swim bladder must be kept inflated
<p>
 -  -  - (> 240 atmospheres)
<p>

<p>
How does gas gland work?
<p>

<p>
 -  - secretes lactic acid into blood
<p>

<p>
 -  - forces localized release of oxygen from hemoglobin
<p>

<p>
 -  - oxygen diffuses into swim bladder
<p>

<p>
 -  - deep-sea fish have longer rete capillaries
<p>
 More on how a fish works
<p>

<p>
Respiration:
<p>

<p>
 -  - gills use countercurrent exchange
<p>

<p>
 -  -  - blood flows opposite direction
<p>
 -  -  - to water pumped in from mouth
<p>

<p>
 -  - active fishes use ram ventilation
<p>

<p>
 -  -  - continuous swimming forces water in
<p>

<p>
 -  - diverse fish can gulp air
<p>

<p>
 Osmoregulation:
<p>

<p>
Freshwater fishes
<p>

<p>
 -  - blood is about 0.25 M
<p>
 -  - freshwater is  0.003 M
<p>

<p>
 -  - they are hyperosmotic regulators
<p>

<p>
 -  -  - use kidney to pump out excess water
<p>
 -  -  - kidney has large "glomerulus"
<p>
 -  -  - also absorb salt with special gill cells
<p>

<p>
Saltwater fishes
<p>

<p>
 -  - blood is about 0.35 M
<p>
 -  - seawater is  1 M
<p>

<p>
 -  - they are hypoosmotic regulators
<p>

<p>
 -  -  - kidney excretes salts
<p>
 -  -  - intestine excrete salty feces
<p>
 -  -  - secrete salt with special gill cells
<p>
-----------------------------
<p>
Amniotes
<p>
Topics:
<p>

<p>
1. - Amniote adaptations for dry land
<p>
2. - Features of the cleidoic egg (with amnion, etc.)
<p>
3. - Early divergences in amniotes
<p>
4. - Evolution of temporal openings
<p>

<p>
Terms:
<p>

<p>
amniote, allantois, yolk, chorion
<p>
3- or 4-chambered hearts
<p>
water conservation organs - ureter vs. loops of Henle
<p>
anapsid, synapsid, sauropsid, diapsid
<p>
lepidosaurs, archosaurs
<p>

<p>
The amnion and cleidoic ("closed") egg
<p>

<p>
Frog: -  - Lizard:
<p>

<p>
many eggs laid in water - Fewer eggs laid on land
<p>

<p>
fully aquatic larval stage - no larval stage
<p>

<p>
metamorphosis to - develops directly to
<p>
juvenile - juvenile
<p>

<p>
sexually mature adult - sexually mature adult
<p>
  mates in water -   mates on land
<p>
  external fertilization -   copulation
<p>

<p>
Cleidoic egg - embryo plus extraembryonic layers
<p>

<p>
amnion is fluid-filled sac that protects embryo
<p>

<p>
yolk sac provides food
<p>

<p>
allantois gathers waste
<p>

<p>
chorion surrounds all the other layers
<p>

<p>
egg is enclosed in semi-permeable shell
<p>

<p>
Leading hypothesis of amniote relationships
<p>
<p>
<FONT COLOR="green" FACE="Monaco"> 
<p>

<p>
Amniota
<p>
 - Synapsida
<p>
 -  - various extinct lineages
<p>
 -  - Mammalia
<p>
 - Sauropsida
<p>
 -  - turtles
<p>
 -  - Diapsida
<p>
 -  -  - Lepidosauria
<p>
 -  -  -  - squamates (lizards incl. snakes)
<p>
 -  -  -  - various extinct marine reptiles
<p>
 -  -  - Archosauria
<p>
 -  -  -  - crocodiles
<p>
 -  -  -  - pterosaurs and dinosaurs
<p>
<p>
</FONT>
<p>

<p>
Two sister clades, synapsids and sauropsids, diverged over 300 Mya
<p>

<p>
Many Paleozoic amniotes are synapsids, so are
<p>
 - more closely related to mammals than to 
<p>
 - reptiles (example at LACM: Dimetridon)
<p>
First mammals were about 220 Mya
<p>
First birds were about 180 Mya
<p>
Big dinosaurs went extinct 65 Mya
<p>

<p>
Main amniote groups are readily distinguished by temporal fenestrae Ð openings behind eye socket
<p>

<p>
Important for recognition Ð functions are obscure
<p>

<p>
Patterns of temporal fenestrae -  - 
<p>
 - fish, early fossil amniotes, turtles 
<p>
 - have no openings, i.e., they are anapsids
<p>

<p>
 -  - synapsid ancestor evolved one pair of 
<p>
 -  - temporal openings - low behind eye
<p>

<p>
 -  - turtles + diapsids is a clade (sauropsids)
<p>
 -  -  - synapomorphy - holes in roof of mouth
<p>
 -  - then:
<p>
 -  -  - diapsid ancestor separately evolved
<p>
 -  -  - two pairs of temporal openings
<p>
 -  -  - (lizards, crocs., birds)
<p>
-----------------------------

<p>
Dinomyths
<p>

<p>
1. - Dinosaurs are big lizards
<p>
2. - Dinosaurs were all big extinct reptiles
<p>
3. - Dinosaurs had a sprawling stance
<p>
4. - Dinosaurs were all big
<p>
5. - The largest dinosaurs lived in swamps
<p>
6. - T. rex ate Brachiosaurus
<p>
7. - Dinosaurs dragged their tail
<p>
8. - Dinosaurs were cold-blooded and sluggish
<p>
9. - Dinosaurs were stupid
<p>
10. - Dinosaurs went extinct
<p>
 1. - Dinosaurs are big lizards
<p>
 -  - actually are closer to crocodiles
<p>
 -  - think birds (see cladogram on p. 573)
<p>
 - 
<p>
2. - Dinosaurs were all big extinct reptiles
<p>
 -  - pterosaurs are sister taxon of dinosaurs
<p>
 -  - ichthyosaurs, etc. are nearer to lizards
<p>
 -  - pelycosaurs are nearer to mammals
<p>

<p>
3. - Dinosaurs had a sprawling stance
<p>
 -  - instead had fully upright stance
<p>
 -  - synapomorphy: hip socket has central hole, 
<p>
 -  - hind limbs directly under body, swing fore-aft
<p>
 -  - (other archosaurs have solid hip socket and
<p>
 -  - sprawling stance)
<p>
 -  - not necessarily faster, but better endurance
<p>
 -  - because movement doesn't constrict the lungs
<p>

<p>
4. - Dinosaurs were all big
<p>
 -  - earliest dinos (240 mya) were small
<p>
 -  - more recent dinos as small as hummingbirds
<p>

<p>
5. - The largest dinosaurs could only support their body weight in swamps
<p>
 -  - an elephant would sink in the mud
<p>
 -  - more likely lived in savanna-like habitat
<p>

<p>
6. - T. rex ate Brachiosaurus
<p>
 -  - T. rex was over 70 million years later
<p>
 -  - T. rex did not live together with cavemen
<p>

<p>
7. - Dinosaurs dragged their tail
<p>
 -  - probably held it upright as in T. rex
<p>

<p>
8. - Dinosaurs were cold-blooded and sluggish
<p>
 -  - some were slow (ectothermic)
<p>
 -  - others were possibly warm-blooded - 
<p>
 -  -  - (endothermic)
<p>
 -  - see Discover (December, 1996)
<p>

<p>
9. - Dinosaurs were stupid
<p>
 -  - active predators are often cunning
<p>
 -  - evidence for nesting and mating behavior
<p>

<p>
10. - Dinosaurs went extinct
<p>
 -  - many did, but not birds
<p>
 -  - birds are dinosaurs, reptiles, vertebrates
<p>
 -  - conventional "dinosaurs" is paraphyletic
<p>
 -  - because it excludes birds
<p>
 - 
<p>
-----------------------------

<p>
Chordates: Mammals
<p>
Topics covered (no notes available)
<p>
1. - Review of Advantages/disadvantages of placenta
<p>
2. - Diversity of placental mammals (Eutheria)
<p>
3. - Limb diversity (see also pp. 639, 647)
<p>
4. - Tooth diversity (see also pp. 605, 702)
<p>
5. - Mammalian diversity
<p>
6. - Amniote extinction events
<p>
 - 
<p>
Amniote extinction events
<p>
 - ÐPaleozoic amniotes
<p>
 - ÐExtinctions at end of Paleozoic Era: - 
<p>
 -  -  - Permian/Triassic (P/Tr) Periods (225 Mya)
<p>
 - ÐMesozoic amniotes
<p>
 - ÐExtinctions at end of Mesozoic Era:
<p>
 -  -  - Cretaceous/Tertiary (K/T) Periods (65 Mya)
<p>
 - ÐCenozoic Era mammals: Eocene Period
<p>
 - ÐEocene/Oligocene extinctions (38 to 29 Mya)
<p>
 - ÐPleistocene and Recent mammals (2 to 0 Mya)
<p>
<p>

<p>


&copy; D. J. Eernisse<p>
These notes may not be reposted or used for any commercial purpose without the
written permission of Prof. Eernisse (deernisse@fullerton.edu).