1
Q
Autapomorphy
A
Allows us to identify a taxa as distinct from all other taxa, but gives us no information regarding how it is related to other taxa
2
Q
Synapomorphy
A
A character that is shared uniquely between a group of taxa; allows us to cluster group of organisms into closely-related clades
3
Q
Monophyletic Group
A
Includes an ancestor and all of its descendants
GOOD :D
4
Q
Paraphyletic Group
A
Begins with an ancestor but does not include all of its descendants
E.g. separation of Reptilia and Aves into two separate classes
BAD!!
5
Q
Chordata
A
Synapomorphies:
- Dorsal hollow nerve cord
- Notochord
- Post-anal tail
Other features:
- Pharyngeal slits
6
Q
Pharyngeal slits
A
Depending on the group, can be used for feeding or respiration
Passageway between external environment and the pharynx
- Formed when inward ectoderm buds and outward endoderm buds meet
Not a synapomorphy for the Chordata but are a very important part of their evolution
7
Q
Dorsal hollow nerve cord
A
Together with the brain, later forms the central nervous system
Formed by the ectoderm, which rolls and forms a hollow tube
8
Q
Notochord
A
Semi-rigid, cartilaginous rod
- Semi-fluid filled cells
- Flexible from side to side but not compressible dorso-ventrally
Functions as support, site for muscle attachment
Becomes the backbone (intervertebral discs anyway) in later taxa
- Is present in embryonic stages
9
Q
Post-anal tail
A
Functions as a propulsive mechanism
Is exactly what it sounds like… tail posterior to the anus
10
Q
Cephalochordata
A
Lancelets & amphioxus
Within Chordata
- Min. 540 MYA
- Marine
Characteristics:
- Notochord runs to the tip of the head
- Single blood vessel that pumps in place of a heart
- Single photoreceptive frontal eye (can determine differences between light/dark)
- Undergo metamorphosis –> ciliated, asymmetrical larvae produce filter-feeding adult
- Have two sexes
11
Q
Olfactores
A
Group within Chordata, contains:
- Urochordata
- Cristozoa
Synapomorphies:
- Numerous molecular traits
- No good morphological synapomorphies
12
Q
Urochordata
A
Within Olfactores
Tunicates, sea squirts
- ~520 MYA
- Marine
Autapomorphies:
- Heart reverses direction of beating every few minutes
- Presence of cellulose in the tunic (body covering); genes for production thought to be horizontally transferred from plants through bacteria
Characteristics:
- Unusually quick mtDNA evolution
- Radical metamorphosis of larvae –> free-swimming & non-feeding larvae with all chordate traits –> lose notochord and tail, dorsal hollow nerve cord reduced, increased paired pharyngeal slits –> sessile, filter-feeding, hermaphroditic adult
- Can be solitary or colonial depending on species
13
Q
Importance of basal chordates
A
- Bioaccumulators
- “Nature’s filters”
- Invasive tunicates can outcompete endemic benthic species and parasitize shellfish farms
14
Q
Vulnerability of basal chordates
A
- Some are eaten (amphioxus)
- Inshore species susceptible to habitat disturbance
- Used in medicine (tunicate substances may be anti-inflammatory, antiviral for herpes, and antitumor)
None have been assessed for conservation purposes yet
Major threat probably habitat disturbance/degradation
15
Q
Cristozoa
A
Group within Oflactores, contains:
- Haikouella t
- Vertebrata
Synapomorphies:
- Proto-vertebrae
- True gills
- Two eyes
- Olfactory lobes
16
Q
Proto-vertebrae
A
Complete notochord has irregular cartilaginous blocks in places
17
Q
True gills
A
- Larger pharyngeal openings
- Cartilaginous bars in pharyngeal openings are much larger and stronger
- Muscles pump water through openings
- Cilia replaced by longer, stronger filaments
18
Q
Haikouella
A
Group within Cristozoa
Extinct
Characteristics:
- Capable of swimming for longer periods of time
- Could select and track prey using sight and smell
- Few large tentacles allow it to move larger food items into mouth
19
Q
Vertebrata
A
Group within Cristozoa, contains:
- Cyclostomata
- Gnathostomata
Synapomorphy: skull
20
Q
Cyclostomata
A
Group within Vertebrata, contains:
- Myxiniformes
- Petromyzontiformes
Round-mouthed fishes
Synapomorphy: white blood cells have unique antigen receptor genes (makes immune system very different)
21
Q
Myxiniformes
A
Group within Cyclostomata
Hagfishes
- Marine
Autapomorphies:
- Ability to absorb amino acids from decaying animals directly through skin/gills
- Slime glands –> ejected mucins absorb water, attach to slime proteins, slows down the movement of water and makes slippery surface that is slime; is ejected on predators to clog gills and disable/distract the animal
- Knotting behaviour –> ties self in knot, moves knot down body to clean, tear flesh, and escape from predators
Characteristics:
- Poorly developed eyes (absent in some species)
- Well-developed chemical and touch senses
- Mainly scavengers, some predation
- Touch-sensitive tentacles around mouth
- Tongue has two rows of keratinized tooth-like structures that ras away flesh
- Produce large, yolk-filled eggs
- No metamorphosis: hatched animals are small adults
22
Q
Petromyzontiformes
A
Group within Cyclostomata
Lampreys
- Marine or freshwater
Characteristics:
- Many spp. are external parasites of fish as adults, some are predators/scavengers, some do not feed at all
- Adults have oral disc full of keratinized tooth-like structures and rasping tongue (w/ same structures)
- Single nostril
- Well-developed eyes
23
Q
Petromyzontiformes - Life cycle
A
Ammocoete larvae hatch, burrow in ground, and live as filter feeders for 3-7 years –> undergo metamorphosis and develop eyes, oral disc, etc. –> adults are parasitic or free living –> build nest in gravel –> spawn –> die
24
Q
Cyclostomata - Uses
A
- Lampreys considered a delicacy, hagfish popular in Korea
- Hagfish skin processed and marketed as “eel skin”
- Eradication of lampreys because they ruin things
25
Gnathostoma
Group within Vertebrata, contains
- Chondrichthyes
- Osteichthyes
Jawed fish
Synapomorphy: jaws
26
Cartilage
Matrix of collagen + proteoglycans + ~75% water
- Both strong and very flexible
Two types: acellular & cellular
Does not repair itself very quickly or well
27
Chondrocytes
Produce the collagen matrix seen in cartilage
28
Chondrichthyes
Group within Gnathostoma, contains
- Holocephali
- Selachii
Cartilaginous fish
Autapomorphy: cartilaginous endoskeleton stiffened with calcium salts
Characteristics:
- Claspers on males
- All have internal fertilization
- High concentration of urea in tissues
29
Holocephali
Group within Chondrichthyes
Ratfish, chimaeras, spookfish
- Marine
Autapomorphies:
- 3 pairs of heavily mineralized tooth plates
- Frontal tenaculum
- Prepelvic tenaculae
Characteristics:
- Long, whiplike caudal fin
- Rabbit-like teeth
- Large spine in front of first dorsal fin
- Swim by using pectoral fins as wings
- Lateral line
- Ampullae of Lorenzi
- Holostyly
- Oviparous and lecithotrophic
30
Claspers
On males only, they are a modification of the cartilaginous rays in the pelvic fin
- Sperm is ejected from the sperm sac, travels through the claspers and into the female
Unique to Chondrichthyes out of extant species, but some extinct jawless fishes had them
31
Lateral line
Pattern of lines on head & running down sides
- Cells are specialized for detecting movement within the water
Make the species that have them look like Franken-fish
32
Ampullae of Lorenzi
Clusters of pores form cells specialized to detect electrical fields
33
Frontal tenaculum
Small club-like structure on the head, just above the eye
- Only on sexually mature males
- Covered in sharp spines
34
Prepelvic tenaculae
Pair of structures that sit in pouches in front of the pelvic fin
- Are extruded during courtship
35
Oviparous
Female lays fertilized eggs outside of the body
36
Lecithotrophic
Embryo gets nutrition solely from the yolk produced by the female
37
Selachii
Group within Gnathostoma
Sharks, skates, rays
- Marine
- Many are apex predators
Characteristics:
- Hyostylic jaw in sharks, Euhyostyly in skates and rays
- Lateral line
- Ampullae of Lorenzi
- Excellent olfaction
- Court using close following, parallel swimming, nudging, and wrestling
Reproductive styles:
- Oviparous & lecithotrophic
- Viviparous & lecithotrophic
- Viviparous & matrotrophic
38
Viviparous
Embryos develop in the female and she gives birth to live young
39
Matrotrophic
After the embryo consumes the yolk, additional nutrition is provided in some way
40
Matrotrophy in Selachii
- Yolk sac-uterus connection
- Oophagy
- Embryophagy
- Uterine milk
- Uterine extensions
41
Oophagy
When the yolk is almost gone, mother ovulates many small eggs into the uterus, which the pups eat
Large ovaries, large pups
42
Embryophagy
When a developing pup reaches a certain size, it kills and eats all the other pups within the uterus
43
Uterine milk
Specialized cells in the uterus produce nutrients that are then ingested by the embryo
44
Uterine extensions
Nutrients are transferred through the embryo's spiracles and directly into the gut
45
Vulnerability of Selachii
- Low fecundity
- Long gestation times
- Slow growth and maturation rates
- Bold behaviour (unlikely to flee)
- Nurseries are close to shore (vulnerable to habitat degradation, hunting, fishing)
- Bycatch, especially of benthic species, which can be captured in trawling nets
46
Osteichthyes
Group within Gnathostomata, contains
- Actinopterygii
- Sarcopterygii
Bony fishes
Synapomorphy: gas bladder
47
Gas bladder
gas-filled structure covered in guanine crystals that make it nearly impermeable to gas leaks
48
Bone
Hard tissue composed of a matrix of collagen/other proteins + ~70% hydroxyapatite crystals + ~5% water
Produced by osteoblasts and can be broken down by osteclasts
- so bone can repair itself
Contains canals though which blood vessels & nerve fibers run
49
Actinopterygii
Group within Osteichthyes
Ray-finned fishes
Autapomorphy: ganoine is present in scales and laid down in growth rings
Characteristics:
- Suction feeding
- Both internal and external fertilization
- Can be monogamous or polygamous
- Can have flexible sex (protogyny, protandry, gynogens)
Parental care:
- No care
- Male-only care (nest building, male broods)
- Female-only care (live young, nests, care)
- Biparental care
50
Suction feeding
1. Expansion of oral cavity through the lowering of the suspensorium, sucks water and food into oral cavity through negative pressure
2. Compress oral cavity by raising suspensorium & ejecting water through gills
3. Swallow large food items, small food items get caught by gill rakers and passed to stomach
Requires close proximity to prey, which can be achieved through stealth or pursuit
51
Monogamy
Pair bonding: one pair mates for the breeding season or life
52
Polygamy
Many mates per breeding season
Includes:
- Promiscuity
- Leks
- Polygyny
- Polyandry
53
Promiscuity
Mass spawning
No obvious mate choice
Basically a fish orgy
54
Leks
Both males and females have multiple partners, but the female is choosing their partner
55
Polygyny
A single territorial male mates with a harem of females
56
Polyandry
A single territorial female mates with multiple males
57
Protogyny
All individuals begin life as a female, and may later change to male
The largest fish in the territory is male, and if he dies the largest female changes sex
58
Protandry
All individuals begin as males and may become female
Largest fish in the territory is female, when she dies the largest male changes sex
59
Gynogens
All-female species
Need males of a different species for fertilization, but offspring are cloned
Arises from a mating mistake in which a hybrid offspring is made that produces diploid rather than haploid eggs
- When she mates with male of either parent species, the sperm is used to fertilize the egg but no genes are incorporated
60
Male broods
Male develops the eggs and fry in the mouth or in a specialized pouch
61
Sarcopterygii
Group within Osteichthyes, contains
- Actinistia
- Dipnoi
- Tetrapoda
Synapomorphy: enlarged clavicle, humerus
62
Actinistia
Group within Sarcopterygii
Coelecanth
Characteristics:
- Hollow-spined 1st dorsal fin
- Lobed pectoral, pelvic, anal, and 2nd dorsal fins
- Caudal fin w/ epicaudal lobe
- High concentration of urea in tissues
- Fat-filled gas bladder
- Skeleton of both bone & cartilage
- Viviparous & lecithotrophic
63
Dipnoi
Group within Sarcopterygii
Lungfish
Characteristics:
- Gas bladder used for respiration
- All extant species are freshwater
- In adulthood have massive, continuously growing tooth plates
- Omnivorous
- Well-developed lateral line & electrosensory systems
- External fertilization
- No or male-only care
- Breathe using lungs (more in S. American & African species)
- Aestivation
64
Aestivation
The act of being in a dormant, underground state when environmental conditions are poor
- Cover self in mucus cocoon and metabolize stored fats
Absent in Australian lungfish, partial in S. American, complete in African
65
Acanthostega
Last step in the move towards Tetrapoda
- Has both fore and hindlimbs but the carpals and tarsals are not fully developed
- Less ankle/wrist flexibility
66
Tetrapoda
Group within Sarcopterygii
Characteristics:
- Four limbs
67
Choana
Posterior nostrils that open up into the mouth and allow for breathing with the mouth closed
68
Amphibia
Group within Tetrapoda, contains
- Gymnophiona
- Caudata
- Anura
Synapomorphies:
- Four or fewer digits on forelimbs
- Four layers of skin (2 epidermis, 2 dermis)
- Cutaneous respiration
69
Cutaneous respiration
Ability to breathe through the skin
This is due to the fact that amphibian skin is so thin
70
Gymnophiona
Amphibian
Caecilians
- Mostly terrestrial, some aquatic
Characteristics:
- Completely limbless
- Annuli
- No post-anal tail
- No scales
- Reduced eyes
- No proof of toxicity, even in bright taxa
- Internal fertilization
- Most viviparous & matrotrophic (uterine milk, sometimes embryonic dentition)
- Remaining oviparous, usually lecithotrophic
71
Caudata
Amphibians
Salamanders & newts
Characteristics:
- Tail in adults
- No scales
- Relatively weak limbs (sometimes hindlimbs are lost altogether)
- No vocal cords
- Many are poisonous
- Mostly internal fertilization, no intermittent organ
- Most oviparous & lecithotrophic
72
Unken posture
Threat display that shows off brightly-coloured bellies
73
Anura
Amphibians
Frogs & toads
Mostly terrestrial, some aquatic
Characteristics:
- Tailless adults
- Shortened body
- Long back legs used for jumping
- Many have toxic secretions, extracted from diet
- Mostly external fertilization
- Vocal courtship, amplexus
- Mostly oviparous & lecithotrophic
- Most have no parental care
74
Types of parental care in Anura
- Egg guarding/carrying by male or female
- Tadpole carrying my male or female
- Tadpole feeding by male or female
- Gastric brooding
- Vocal sac brooding
75
Gastric brooding
Female swallows fertilized eggs, which develop into froglets in her stomach
76
Vocal sac brooding
Male guards developing eggs & swallows tadpoles when they hatch
Develop into froglets in vocal sac
77
Threats to Anura
Main threats to all life stages:
- Climate change
- Chytrid fungus
- Habitat loss
Only affect development:
- Pollution
- Acid rain
- UV light
78
Evolution of Jaws
1. Pharyngeal Slits
2. True gills
3. Jawless fishes
4. Jaws
79
Visceral arch
Pair of acellular cartilaginous rods form an arch and hold open a pharyngeal slit
80
True gills
```
Visceral arch rods made of cellular cartilage
Cilia replaced by rays
Reduction in number of arches
Increase in size of arches
Function for respiration
```
81
Pharyngeal Anatomy of Jawless Fishes
1st Visceral Arch: Mandibular Arch
2nd Visceral Arch: Hyoid Arch
Remaining: Branchial Arches
82
Jaw Anatomy
Mandibular arch modified to form components of upper & lower jaw
- Used in feeding
Rays on hyoid arch support gills
Branchial arches are gills
- Respiration
83
Epimandibula
Upper jaw
84
Ceratomandibula
Lower jaw
85
Epihyoid
Upper of hyoid arches
86
Hyomandibula
Epihyoid
87
Ceratohyoid
Lower hyoid arch
88
Autodiastylic jaw
Upper jaw suspended from skull by ligaments
Hyoid arch has rays that support gill openings
89
Holostylic jaw
Upper jaw fused to braincase
Hyoid arch has rays
Some rays enlarge to form operculum
Holocephali
90
Hyostylic jaw
Upper jaw suspended from skull by one ligament
Hyomandibula articulates with skull & upper jaw
Ceratohyoid articulates with lower jaw
Feeding: upper jaw thrust forward by hyomandibula, lower jaw closes
Sharks (Selachii)
91
Euhyostylic jaw
Jaws supported by hyomandibula and no ligament
Both upper and lower jaw can be protruded from mouth
Ceratohyoid reduced or absent
Skates/rays
92
Hyostylic jaw, most derived
Jaws supported by chain of three bones known as the suspensorium
Very flexible jaws
Actinopterygii
93
Suspensorium
Chain of three bones that connects the jaws with the skull
Hyomandibula --> symplectic --> quadrate
94
Floating - Condrychthyes
Cartilaginous skeleton is very light (already close to water)
Liver full of lipids
Can change depth rapidly, but must swim & exhaust energy to do so
95
Floating - Osteichthyes
Can have lipids in skin/bones/liver
Most commonly use a gas bladder
- Slower changes because need to control volume of gas in bladder before changing depths or it will burst
96
Types of gas bladder
1. Physostomous type 1
2. Physostomous type 2
3. Physoclistous
97
Physostomous type 1
Pneumatic duct connects to gas bladder
Fills bladder by gulping air at surface, empty bladder by opening pneumatic duct and spitting out air
98
Physostomous type 2
To fill, gas cells in bladder secrete lactic acid into the rete mirabile, the hemoglobin releases oxygen which diffused into the gas bladder
To empty, fish spits out air
99
Physoclistous
Gas bladder is now completely separate from the esophagus
To fill the bladder, gas cells secrete lactic acid into rete mirabile and oxygen released by hemoglobin diffuses into gas bladder
To empty, muscles contract to reveal oval of no guanine crystals, through which air diffuses into capillary bed along a vein
100
Evolution of tetrapod limbs
Evolution of forelimb and hindlimb are decoupled
Forelimb usually changes before the hindlimb
Happened while the animals were still aquatic
EEB267
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