BIOL 204 Midterm: Lab 2 - Phylogeny
February 11, 2018
3:00 AM
Definition/Function
For Phylogeny
Phylogenetic Tree - Hypothesis of the evolutionary relationships among
taxa
Based on shared phenotypic characters and genetic similarities
○
-
Taxon - Named group of organisms
-
Character - feature of an organism that can be observed
Morphological
○
Developmental
○
Behavioural
○
Physiological/biochemical
○
Important to consider all stages, because may only be present in
some
○
-
Character State -minimum of 2
-
Shared Character - 2 or more have same character states via living
organisms and fossil examination
-
Homologous - inherited from common ancestor
-
Convergence - Character state is independently inherited
Look for position on the tree and MRCA
-
-
Deuterostome Development --> Blastopore becomes anus
-
Protostome Development --> Blastopore becomes mouth
-
Ancestral (plesiomorphic) - character state evolved a long time ago
-
Derived (apomorphic) - evolved recently
Depends on the taxon we're looking at
-
-
Synapomorphy - Shared by two or more taxa and MRCA
Help identification of phylogeny
-
-
Parisomy - Simplest explanation possible
Shared derived characters with the fewest evolutionary changes
possible
-
-
For Characters
Dorsal Hollow Nerve Chord
Hollow
-
Fluid Filled
-
Formed from invagination of ectoderm
-
During neurulation
-
-
Notochord
Slender and flexible rod
-
From Mesoderm
-
Located dorsal to the gut, but ventral to CNS
-
Can lateral flexion - bending side to side
-
No Axial Compression - getting shorter from end to end
-
Allow Lateral undulation
-
-
Pharyngeal slits
Opening to the walls of the pharynx
-
Arranged anterior to posterior
-
-
Post-anal Tail
Muscular structure located posterior to the anus
-
Used for locomotion
-
-
Cranium (Skull)
Supports and protects the brain and sensory structures
-
Composed of cartilage and or bone
-
-
Tunic
Secreted by epidermis
-
Surrounds the body
-
Composed of protein tunicin and polysaccharide cellulose
-
-
Myomeres
Segmental blocks of skeletal muscle
-
Separated by Myosepta - layers of connective tissue
-
Apart of the body wall
-
Arranged metametically (in series from anterior to posterior)
-
Arise from myotome epimere mesoderm
-
-
Atlas - specialized cervical vertebra
Allows head movement up and down independent of trunk
-
-
Axis - allows side to side head movement
-
Endostyle
Produces sticky mucus to trap small food particles
-
Homologous to thyroid gland
-
-
Operculum - large bony flap that protects the opercular chamber
-
Ray fins - thin layer of skin overlying a supportive framework of rays
Composed of bone/cartilage/keratin
-
Muscles are located in the body wall and do not extend into the fin
-
-
Amnion - waterproof chamber to prevent dessication
-
Anapsid - no temporal fenestrae
-
Synapsid - one pair of temporal fenestrae
-
Diapsid - Two pairs of temporal Fenestrae
-
Dentary - Lower jaw and connects with squamosal bone
-
Embryology Origins
Ectoderm
Dorsal nerve chord
-
Tunic
-
-
Mesoderm
Notochord
-
Epimere mesoderm
Myomeres
§
-
-
Morphological Differences
Table 1.
Characters Cucuma
ria
Petromy
zon
Branchios
toma
Balanogl
ossus
Clavelin
a
Dorsal hollow nerve Cord - + + - +
Notochord - + + - +
Pharyngeal Slits - + + + +
Post-anal Tail - + + - +
Cranium - + - - -
Tunic - - - - +
Myomeres - + + - -
Location and How to Identify
Examples
Deutrostome vs Protostome
Deutrostrome
Chordates
§
Vertebrates
§
Echinodermata
§
Hemichordata
§
-
Protostome
Molluscs
§
Arthropods
§
Annelids
§
-
-
Ancestral vs Derived
Hair
Derived for mammals
§
Ancestral for Rodentia
§
-
Legs
Derived for tetrapods
§
Ancestral for mammals
§
-
Deuterostome Development
Derived for Deuterostomes
§
Ancestral for Vertebrates
§
-
-
How to draw a phylogenetic Tree?
Define in group and outgroup to polarize character states to outgroup
Character states in outgroup is ancestral a.
Derived if not present in outgroup but present in the ingroup b.
Outgroup is closely related but not part of ingroup c.
1.
Select characteristics2.
Which taxa of the ingroup share each derived character trait
Collect data from representative species a.
3.
Group the ones with the most synapomorphies via a character matrix
Present or absent a.
4.
Helpful using variations in molecular markers to infer phylogenetic
relationships
5.
Phyla and Descriptions
Echinodermata
Representative Species
Sea stars
§
Sea Urchins
§
Sea Cucumbers
§
Brittle stars
§
Feather Stars
§
-
Identifying Features
Undergo dramatic metamorphosis
§
Larva have bilateral symmetry
§
Adults have pentaradial symmetry
§
-
Hemichordata
Representative Species
Acorn Worms
§
pterobranchs
§
-
Identifying Features
Have 3 major regions
Proboscis□
Collar□
Anus□
§
Share some but not all characteristics of chordates
§
-
Fig 1. Acorn worm external Features
Chordata
Urochordata
Representative Species
Tunicates □
Seaquires□
§
Identifying Features
Dramatic metamorphosis□
Larvae move using lateral undulation with post-anal tail □
Adults are sessile filter feeders□
Pharyngeal slits form large filtering basket
Cilia pump water through buccal siphon into
pharynx through the slits into the atrium then exit
the body through the atrial siphon
®
□
Endostyle
Produces sticky mucus to trap small food particles
®
Homologous to thyroid gland
®
□
§
-
Fig 2. larva and adult of Urochordata
Cephalochordata
Representative Species
Lancelets□
§
Identifying Features
Use pharyngeal slits for filter feeding
Water enters mouth into pharynx then passes slits
into atrium and leave through atriopore
®
Bars of pharynx covered with stick mucus from
endostyle
®
□
Different from urochordata by not undergoing dramatic
metamorphosis
Looks like miniature adults without gonads
®
□
Both Adults and Larvae swim with lateral undulations □
§
-
Fig 3a. Myomeres
Fig 3b. Cephalochordate Cross section and Whole Mount
Vertebrata
Identifying Features
Most diverse taxon □
Most have vertebrae that protect dorsal hollow nerve
cord (spinal Cord)
□
Cranium protects head□
Specialized sense organs□
Closed circulatory system□
Muscular Heart with Chambers separated by valves□
Red blood cells □
All taxa have notochords as embryo, but may be lost □
§
Myxinoidea
Representative Species
Hagfish□
§
Identifying Features
Don't have jaws □
Marine and deep water scavengers
Eat dead or dying animals that sink to ocean floor
®
□
Basic eyes □
One nostril □
One posterior fin□
Sucking mouths
With rasping projections on the tongue
®
□
Specialized gland for slime production and released from
skin pores to deter predators
□
No scales, but have cartilaginous skeleton □
Large notochord□
No Vertebrae□
§
-
Petromyzontida
Representative Species
Lampreys□
§
Identifying Features
Like Hagfish because:
Don't have jaws
®
Single nostril
®
Cartilaginous skeleton
®
□
Like vertebrates:
Cranium
®
Sensory organs
®
Tiny vertebrae - Small cartilaginous arches located
on dorsal surface
®
□
Live in fresh water and burrow into sediments to filter
feed
□
Larva is called ammocoetes
Look similar to cephalochordates
®
But different because cephalochordates use cilia to
pump water, these use muscular pharynx with
cartilaginous baes to filter feed
®
Sticky mucous from pharyngeal slits are produced
from goblet cells (Lateral region), despite having
endostyle
®
□
Metamorphosis after 3-7 years
Endostyle becomes thyroid gland
®
Migration to lake or ocean
®
May be parasitic (attach to fish host and rasp away
skin to suck blood)
®
or not feed at all live off fat reserves from larval
stage
®
□
§
-
Fig 4. Larval vs Adults of Lamprey
Fig 5. Adult Lamprey Cross section
Chondrichthyes
Representative Species
Elsmobranchii
Shark
®
rays
®
□
Holocephali
Chimeras
®
Rat fish
®
□
§
Identifying Features
5-6 pairs of external gill slits□
Spiracle - Intake water when breathing --> reduced gill
slit
□
Placoid scales □
No gas-filled swim bladder for buoyancy□
Large liver for oil production --> Helps buoyancy□
Intestine with internal spiral valve allows digested food
to descend
□
§
-
Teleostomi
Identifying features
Most have internal inflatable gas bladders
®
Bony fish were originally called Osteichthyes
®
□
Actinopterygii
Representative Species
Most fish species
®
□
Identifying Features
Swim bladders
®
Highly kinetic jaws
®
One pair of external gill openings because housed
in common chamber (opercular chamber)
®
Operculum - large bony flap that protects the
opercular chamber
®
Ray fins - thin layer of skin overlying a supportive
framework of rays
Composed of bone/cartilage/keratin
§
Muscles are located in the body wall and do
not extend into the fin
§
®
□
§
Sarcopterygii
Representative Species
Lung fish
®
Coelacanths
®
□
Identifying Features
Lungs used for gas exchange with air
®
1 external gill openhing because of opercular
chamber and operculum
®
Have fleshy fins
Contain both bone and muscle
Located in body wall and within fin
}
§
®
□
§
Tetrapods
Identifying features
Muscular limbs
§
Defined joins and digits
§
Atlas - specialized cervical vertebra
Allows head movement up and down
independent of trunk
}
§
®
Amphibia
Representative Species
Urodela
Salamanders
}
Newts
}
§
Anura
Frogs
}
Toads
}
§
Gymnophiona
Caecilians
}
Apodans
}
§
®
Identifying Features
Lungs used for gas exchange with air
§
Eggs with no shells or membranes
§
Lay eggs in water
§
Larvae usually breathe with gills
§
Adult have paired lungs
§
Cutaneous gas exchange - through the skin
Mucous glands and poison glands
}
§
Only atlas as the cervical vertebra
§
®
□
Amniotes
Identifying Features
Several extraembryonic membranes
Amnion - waterproof chamber to
prevent dessication
Allow egg laying in terrestrial
environments
w
–
}
Temporal fenestraw
}
2 specialized cervical vetebrae
Atlas and axis
–
}
Can have more cervical vertebrae
}
Use lungs to exchange gas
}
§
Sauropsida
Representative Species
Parareptilia
Turtles
–
}
Eureptilia
Lepidosauria
Snake
w
Lizards
w
Legless lizards
w
Tuatara
w
–
Archosauria
Crocodilia
Crocodiles
w
Alligators
w
Gharials
w
Caimans
w
w
Aves
Birds
w
w
–
}
§
Identifying Features
Parareptilia --> anapsid
}
Eureptilia --> diapsid
}
Aves
Endothermic
–
Efficient respiratory system
–
Feathers and wings to adapt for
weight reduction
–
Bipedal
–
Beak composed of keratin
–
}
§
®
Mammalia
Representative Species
Monotremes
Platypus
–
echidna
–
}
Metatherias
Opossums
–
Kangaroos
–
}
Eutheria
Most mammals
–
}
§
Identifying Features
Synapsid skull
}
Hair
}
Mammary glands
}
Sebaceous (oil) gkabds
}
Sweat glands
}
Endothermic
}
3 bones in the middle ear
}
Large brains
}
Lower jaw is a single bone called the
dentary
Forms joint with the squamosal
bone
–
}
Monotremes
Lay shelled eggs
–
}
Metatherias
Marsupials
–
Young is born at a very early age
and then crawl into mother's
pouch
–
}
Eutheria
Embryo develops longer period
before birth
–
}
§
®
□
§
-
Lab 2 -Phylogeny
February 11, 2018
3:19 AM
February 11, 2018
3:00 AM
Definition/Function
For Phylogeny
Phylogenetic Tree - Hypothesis of the evolutionary relationships among
taxa
Based on shared phenotypic characters and genetic similarities
○
-
Taxon - Named group of organisms
-
Character - feature of an organism that can be observed
Morphological
○
Developmental
○
Behavioural
○
Physiological/biochemical
○
Important to consider all stages, because may only be present in
some
○
-
Character State -minimum of 2
-
Shared Character - 2 or more have same character states via living
organisms and fossil examination
-
Homologous - inherited from common ancestor
-
Convergence - Character state is independently inherited
Look for position on the tree and MRCA
-
-
Deuterostome Development --> Blastopore becomes anus
-
Protostome Development --> Blastopore becomes mouth
-
Ancestral (plesiomorphic) - character state evolved a long time ago
-
Derived (apomorphic) - evolved recently
Depends on the taxon we're looking at
-
-
Synapomorphy - Shared by two or more taxa and MRCA
Help identification of phylogeny
-
-
Parisomy - Simplest explanation possible
Shared derived characters with the fewest evolutionary changes
possible
-
-
For Characters
Dorsal Hollow Nerve Chord
Hollow
-
Fluid Filled
-
Formed from invagination of ectoderm
-
During neurulation
-
-
Notochord
Slender and flexible rod
-
From Mesoderm
-
Located dorsal to the gut, but ventral to CNS
-
Can lateral flexion - bending side to side
-
No Axial Compression - getting shorter from end to end
-
Allow Lateral undulation
-
-
Pharyngeal slits
Opening to the walls of the pharynx
-
Arranged anterior to posterior
-
-
Post-anal Tail
Muscular structure located posterior to the anus
-
Used for locomotion
-
-
Cranium (Skull)
Supports and protects the brain and sensory structures
-
Composed of cartilage and or bone
-
-
Tunic
Secreted by epidermis
-
Surrounds the body
-
Composed of protein tunicin and polysaccharide cellulose
-
-
Myomeres
Segmental blocks of skeletal muscle
-
Separated by Myosepta - layers of connective tissue
-
Apart of the body wall
-
Arranged metametically (in series from anterior to posterior)
-
Arise from myotome epimere mesoderm
-
-
Atlas - specialized cervical vertebra
Allows head movement up and down independent of trunk
-
-
Axis - allows side to side head movement
-
Endostyle
Produces sticky mucus to trap small food particles
-
Homologous to thyroid gland
-
-
Operculum - large bony flap that protects the opercular chamber
-
Ray fins - thin layer of skin overlying a supportive framework of rays
Composed of bone/cartilage/keratin
-
Muscles are located in the body wall and do not extend into the fin
-
-
Amnion - waterproof chamber to prevent dessication
-
Anapsid - no temporal fenestrae
-
Synapsid - one pair of temporal fenestrae
-
Diapsid - Two pairs of temporal Fenestrae
-
Dentary - Lower jaw and connects with squamosal bone
-
Embryology Origins
Ectoderm
Dorsal nerve chord
-
Tunic
-
-
Mesoderm
Notochord
-
Epimere mesoderm
Myomeres
§
-
-
Morphological Differences
Table 1.
Characters Cucuma
ria
Petromy
zon
Branchios
toma
Balanogl
ossus
Clavelin
a
Dorsal hollow nerve Cord - + + - +
Notochord - + + - +
Pharyngeal Slits - + + + +
Post-anal Tail - + + - +
Cranium - + - - -
Tunic - - - - +
Myomeres - + + - -
Location and How to Identify
Examples
Deutrostome vs Protostome
Deutrostrome
Chordates
§
Vertebrates
§
Echinodermata
§
Hemichordata
§
-
Protostome
Molluscs
§
Arthropods
§
Annelids
§
-
-
Ancestral vs Derived
Hair
Derived for mammals
§
Ancestral for Rodentia
§
-
Legs
Derived for tetrapods
§
Ancestral for mammals
§
-
Deuterostome Development
Derived for Deuterostomes
§
Ancestral for Vertebrates
§
-
-
How to draw a phylogenetic Tree?
Define in group and outgroup to polarize character states to outgroup
Character states in outgroup is ancestral a.
Derived if not present in outgroup but present in the ingroup b.
Outgroup is closely related but not part of ingroup c.
1.
Select characteristics2.
Which taxa of the ingroup share each derived character trait
Collect data from representative species a.
3.
Group the ones with the most synapomorphies via a character matrix
Present or absent a.
4.
Helpful using variations in molecular markers to infer phylogenetic
relationships
5.
Phyla and Descriptions
Echinodermata
Representative Species
Sea stars
§
Sea Urchins
§
Sea Cucumbers
§
Brittle stars
§
Feather Stars
§
-
Identifying Features
Undergo dramatic metamorphosis
§
Larva have bilateral symmetry
§
Adults have pentaradial symmetry
§
-
Hemichordata
Representative Species
Acorn Worms
§
pterobranchs
§
-
Identifying Features
Have 3 major regions
Proboscis□
Collar□
Anus□
§
Share some but not all characteristics of chordates
§
-
Fig 1. Acorn worm external Features
Chordata
Urochordata
Representative Species
Tunicates □
Seaquires□
§
Identifying Features
Dramatic metamorphosis□
Larvae move using lateral undulation with post-anal tail □
Adults are sessile filter feeders□
Pharyngeal slits form large filtering basket
Cilia pump water through buccal siphon into
pharynx through the slits into the atrium then exit
the body through the atrial siphon
®
□
Endostyle
Produces sticky mucus to trap small food particles
®
Homologous to thyroid gland
®
□
§
-
Fig 2. larva and adult of Urochordata
Cephalochordata
Representative Species
Lancelets□
§
Identifying Features
Use pharyngeal slits for filter feeding
Water enters mouth into pharynx then passes slits
into atrium and leave through atriopore
®
Bars of pharynx covered with stick mucus from
endostyle
®
□
Different from urochordata by not undergoing dramatic
metamorphosis
Looks like miniature adults without gonads
®
□
Both Adults and Larvae swim with lateral undulations □
§
-
Fig 3a. Myomeres
Fig 3b. Cephalochordate Cross section and Whole Mount
Vertebrata
Identifying Features
Most diverse taxon □
Most have vertebrae that protect dorsal hollow nerve
cord (spinal Cord)
□
Cranium protects head□
Specialized sense organs□
Closed circulatory system□
Muscular Heart with Chambers separated by valves□
Red blood cells □
All taxa have notochords as embryo, but may be lost □
§
Myxinoidea
Representative Species
Hagfish□
§
Identifying Features
Don't have jaws □
Marine and deep water scavengers
Eat dead or dying animals that sink to ocean floor
®
□
Basic eyes □
One nostril □
One posterior fin□
Sucking mouths
With rasping projections on the tongue
®
□
Specialized gland for slime production and released from
skin pores to deter predators
□
No scales, but have cartilaginous skeleton □
Large notochord□
No Vertebrae□
§
-
Petromyzontida
Representative Species
Lampreys□
§
Identifying Features
Like Hagfish because:
Don't have jaws
®
Single nostril
®
Cartilaginous skeleton
®
□
Like vertebrates:
Cranium
®
Sensory organs
®
Tiny vertebrae - Small cartilaginous arches located
on dorsal surface
®
□
Live in fresh water and burrow into sediments to filter
feed
□
Larva is called ammocoetes
Look similar to cephalochordates
®
But different because cephalochordates use cilia to
pump water, these use muscular pharynx with
cartilaginous baes to filter feed
®
Sticky mucous from pharyngeal slits are produced
from goblet cells (Lateral region), despite having
endostyle
®
□
Metamorphosis after 3-7 years
Endostyle becomes thyroid gland
®
Migration to lake or ocean
®
May be parasitic (attach to fish host and rasp away
skin to suck blood)
®
or not feed at all live off fat reserves from larval
stage
®
□
§
-
Fig 4. Larval vs Adults of Lamprey
Fig 5. Adult Lamprey Cross section
Chondrichthyes
Representative Species
Elsmobranchii
Shark
®
rays
®
□
Holocephali
Chimeras
®
Rat fish
®
□
§
Identifying Features
5-6 pairs of external gill slits□
Spiracle - Intake water when breathing --> reduced gill
slit
□
Placoid scales □
No gas-filled swim bladder for buoyancy□
Large liver for oil production --> Helps buoyancy□
Intestine with internal spiral valve allows digested food
to descend
□
§
-
Teleostomi
Identifying features
Most have internal inflatable gas bladders
®
Bony fish were originally called Osteichthyes
®
□
Actinopterygii
Representative Species
Most fish species
®
□
Identifying Features
Swim bladders
®
Highly kinetic jaws
®
One pair of external gill openings because housed
in common chamber (opercular chamber)
®
Operculum - large bony flap that protects the
opercular chamber
®
Ray fins - thin layer of skin overlying a supportive
framework of rays
Composed of bone/cartilage/keratin
§
Muscles are located in the body wall and do
not extend into the fin
§
®
□
§
Sarcopterygii
Representative Species
Lung fish
®
Coelacanths
®
□
Identifying Features
Lungs used for gas exchange with air
®
1 external gill openhing because of opercular
chamber and operculum
®
Have fleshy fins
Contain both bone and muscle
Located in body wall and within fin
}
§
®
□
§
Tetrapods
Identifying features
Muscular limbs
§
Defined joins and digits
§
Atlas - specialized cervical vertebra
Allows head movement up and down
independent of trunk
}
§
®
Amphibia
Representative Species
Urodela
Salamanders
}
Newts
}
§
Anura
Frogs
}
Toads
}
§
Gymnophiona
Caecilians
}
Apodans
}
§
®
Identifying Features
Lungs used for gas exchange with air
§
Eggs with no shells or membranes
§
Lay eggs in water
§
Larvae usually breathe with gills
§
Adult have paired lungs
§
Cutaneous gas exchange - through the skin
Mucous glands and poison glands
}
§
Only atlas as the cervical vertebra
§
®
□
Amniotes
Identifying Features
Several extraembryonic membranes
Amnion - waterproof chamber to
prevent dessication
Allow egg laying in terrestrial
environments
w
–
}
Temporal fenestraw
}
2 specialized cervical vetebrae
Atlas and axis
–
}
Can have more cervical vertebrae
}
Use lungs to exchange gas
}
§
Sauropsida
Representative Species
Parareptilia
Turtles
–
}
Eureptilia
Lepidosauria
Snake
w
Lizards
w
Legless lizards
w
Tuatara
w
–
Archosauria
Crocodilia
Crocodiles
w
Alligators
w
Gharials
w
Caimans
w
w
Aves
Birds
w
w
–
}
§
Identifying Features
Parareptilia --> anapsid
}
Eureptilia --> diapsid
}
Aves
Endothermic
–
Efficient respiratory system
–
Feathers and wings to adapt for
weight reduction
–
Bipedal
–
Beak composed of keratin
–
}
§
®
Mammalia
Representative Species
Monotremes
Platypus
–
echidna
–
}
Metatherias
Opossums
–
Kangaroos
–
}
Eutheria
Most mammals
–
}
§
Identifying Features
Synapsid skull
}
Hair
}
Mammary glands
}
Sebaceous (oil) gkabds
}
Sweat glands
}
Endothermic
}
3 bones in the middle ear
}
Large brains
}
Lower jaw is a single bone called the
dentary
Forms joint with the squamosal
bone
–
}
Monotremes
Lay shelled eggs
–
}
Metatherias
Marsupials
–
Young is born at a very early age
and then crawl into mother's
pouch
–
}
Eutheria
Embryo develops longer period
before birth
–
}
§
®
□
§
-
Lab 2 -Phylogeny
February 11, 2018 3:19 AM
February 11, 2018
3:00 AM
Definition/Function
For Phylogeny
Phylogenetic Tree - Hypothesis of the evolutionary relationships among
taxa
Based on shared phenotypic characters and genetic similarities
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Taxon - Named group of organisms
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Character - feature of an organism that can be observed
Morphological
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Developmental
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Behavioural
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Physiological/biochemical
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Important to consider all stages, because may only be present in
some
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Character State -minimum of 2
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Shared Character - 2 or more have same character states via living
organisms and fossil examination
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Homologous - inherited from common ancestor
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Convergence - Character state is independently inherited
Look for position on the tree and MRCA
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Deuterostome Development --> Blastopore becomes anus
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Protostome Development --> Blastopore becomes mouth
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Ancestral (plesiomorphic) - character state evolved a long time ago
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Derived (apomorphic) - evolved recently
Depends on the taxon we're looking at
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Synapomorphy - Shared by two or more taxa and MRCA
Help identification of phylogeny
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Parisomy - Simplest explanation possible
Shared derived characters with the fewest evolutionary changes
possible
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For Characters
Dorsal Hollow Nerve Chord
Hollow
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Fluid Filled
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Formed from invagination of ectoderm
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During neurulation
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Notochord
Slender and flexible rod
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From Mesoderm
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Located dorsal to the gut, but ventral to CNS
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Can lateral flexion - bending side to side
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No Axial Compression - getting shorter from end to end
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Allow Lateral undulation
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Pharyngeal slits
Opening to the walls of the pharynx
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Arranged anterior to posterior
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Post-anal Tail
Muscular structure located posterior to the anus
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Used for locomotion
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Cranium (Skull)
Supports and protects the brain and sensory structures
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Composed of cartilage and or bone
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Tunic
Secreted by epidermis
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Surrounds the body
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Composed of protein tunicin and polysaccharide cellulose
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Myomeres
Segmental blocks of skeletal muscle
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Separated by Myosepta - layers of connective tissue
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Apart of the body wall
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Arranged metametically (in series from anterior to posterior)
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Arise from myotome epimere mesoderm
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Atlas - specialized cervical vertebra
Allows head movement up and down independent of trunk
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Axis - allows side to side head movement
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Endostyle
Produces sticky mucus to trap small food particles
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Homologous to thyroid gland
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Operculum - large bony flap that protects the opercular chamber
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Ray fins - thin layer of skin overlying a supportive framework of rays
Composed of bone/cartilage/keratin
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Muscles are located in the body wall and do not extend into the fin
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Amnion - waterproof chamber to prevent dessication
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Anapsid - no temporal fenestrae
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Synapsid - one pair of temporal fenestrae
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Diapsid - Two pairs of temporal Fenestrae
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Dentary - Lower jaw and connects with squamosal bone
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Embryology Origins
Ectoderm
Dorsal nerve chord
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Tunic
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Mesoderm
Notochord
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Epimere mesoderm
Myomeres
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Morphological Differences
Table 1.
Characters
Cucuma
ria
Petromy
zon
Branchios
toma
Balanogl
ossus
Clavelin
a
Dorsal hollow nerve Cord
-
+
+
-
+
Notochord - + + - +
Pharyngeal Slits - + + + +
Post-anal Tail - + + - +
Cranium - + - - -
Tunic - - - - +
Myomeres - + + - -
Location and How to Identify
Examples
Deutrostome vs Protostome
Deutrostrome
Chordates
§
Vertebrates
§
Echinodermata
§
Hemichordata
§
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Protostome
Molluscs
§
Arthropods
§
Annelids
§
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Ancestral vs Derived
Hair
Derived for mammals
§
Ancestral for Rodentia
§
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Legs
Derived for tetrapods
§
Ancestral for mammals
§
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Deuterostome Development
Derived for Deuterostomes
§
Ancestral for Vertebrates
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How to draw a phylogenetic Tree?
Define in group and outgroup to polarize character states to outgroup
Character states in outgroup is ancestral a.
Derived if not present in outgroup but present in the ingroup b.
Outgroup is closely related but not part of ingroup c.
1.
Select characteristics2.
Which taxa of the ingroup share each derived character trait
Collect data from representative species a.
3.
Group the ones with the most synapomorphies via a character matrix
Present or absent a.
4.
Helpful using variations in molecular markers to infer phylogenetic
relationships
5.
Phyla and Descriptions
Echinodermata
Representative Species
Sea stars
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Sea Urchins
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Sea Cucumbers
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Brittle stars
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Feather Stars
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Identifying Features
Undergo dramatic metamorphosis
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Larva have bilateral symmetry
§
Adults have pentaradial symmetry
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Hemichordata
Representative Species
Acorn Worms
§
pterobranchs
§
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Identifying Features
Have 3 major regions
Proboscis□
Collar□
Anus□
§
Share some but not all characteristics of chordates
§
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Fig 1. Acorn worm external Features
Chordata
Urochordata
Representative Species
Tunicates □
Seaquires□
§
Identifying Features
Dramatic metamorphosis□
Larvae move using lateral undulation with post-anal tail □
Adults are sessile filter feeders□
Pharyngeal slits form large filtering basket
Cilia pump water through buccal siphon into
pharynx through the slits into the atrium then exit
the body through the atrial siphon
®
□
Endostyle
Produces sticky mucus to trap small food particles
®
Homologous to thyroid gland
®
□
§
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Fig 2. larva and adult of Urochordata
Cephalochordata
Representative Species
Lancelets□
§
Identifying Features
Use pharyngeal slits for filter feeding
Water enters mouth into pharynx then passes slits
into atrium and leave through atriopore
®
Bars of pharynx covered with stick mucus from
endostyle
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□
Different from urochordata by not undergoing dramatic
metamorphosis
Looks like miniature adults without gonads
®
□
Both Adults and Larvae swim with lateral undulations □
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Fig 3a. Myomeres
Fig 3b. Cephalochordate Cross section and Whole Mount
Vertebrata
Identifying Features
Most diverse taxon □
Most have vertebrae that protect dorsal hollow nerve
cord (spinal Cord)
□
Cranium protects head□
Specialized sense organs□
Closed circulatory system□
Muscular Heart with Chambers separated by valves□
Red blood cells □
All taxa have notochords as embryo, but may be lost □
§
Myxinoidea
Representative Species
Hagfish□
§
Identifying Features
Don't have jaws □
Marine and deep water scavengers
Eat dead or dying animals that sink to ocean floor
®
□
Basic eyes □
One nostril □
One posterior fin□
Sucking mouths
With rasping projections on the tongue
®
□
Specialized gland for slime production and released from
skin pores to deter predators
□
No scales, but have cartilaginous skeleton □
Large notochord□
No Vertebrae□
§
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Petromyzontida
Representative Species
Lampreys□
§
Identifying Features
Like Hagfish because:
Don't have jaws
®
Single nostril
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Cartilaginous skeleton
®
□
Like vertebrates:
Cranium
®
Sensory organs
®
Tiny vertebrae - Small cartilaginous arches located
on dorsal surface
®
□
Live in fresh water and burrow into sediments to filter
feed
□
Larva is called ammocoetes
Look similar to cephalochordates
®
But different because cephalochordates use cilia to
pump water, these use muscular pharynx with
cartilaginous baes to filter feed
®
Sticky mucous from pharyngeal slits are produced
from goblet cells (Lateral region), despite having
endostyle
®
□
Metamorphosis after 3-7 years
Endostyle becomes thyroid gland
®
Migration to lake or ocean
®
May be parasitic (attach to fish host and rasp away
skin to suck blood)
®
or not feed at all live off fat reserves from larval
stage
®
□
§
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Fig 4. Larval vs Adults of Lamprey
Fig 5. Adult Lamprey Cross section
Chondrichthyes
Representative Species
Elsmobranchii
Shark
®
rays
®
□
Holocephali
Chimeras
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Rat fish
®
□
§
Identifying Features
5-6 pairs of external gill slits□
Spiracle - Intake water when breathing --> reduced gill
slit
□
Placoid scales □
No gas-filled swim bladder for buoyancy□
Large liver for oil production --> Helps buoyancy□
Intestine with internal spiral valve allows digested food
to descend
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§
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Teleostomi
Identifying features
Most have internal inflatable gas bladders
®
Bony fish were originally called Osteichthyes
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Actinopterygii
Representative Species
Most fish species
®
□
Identifying Features
Swim bladders
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Highly kinetic jaws
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One pair of external gill openings because housed
in common chamber (opercular chamber)
®
Operculum - large bony flap that protects the
opercular chamber
®
Ray fins - thin layer of skin overlying a supportive
framework of rays
Composed of bone/cartilage/keratin
§
Muscles are located in the body wall and do
not extend into the fin
§
®
□
§
Sarcopterygii
Representative Species
Lung fish
®
Coelacanths
®
□
Identifying Features
Lungs used for gas exchange with air
®
1 external gill openhing because of opercular
chamber and operculum
®
Have fleshy fins
Contain both bone and muscle
Located in body wall and within fin
}
§
®
□
§
Tetrapods
Identifying features
Muscular limbs
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Defined joins and digits
§
Atlas - specialized cervical vertebra
Allows head movement up and down
independent of trunk
}
§
®
Amphibia
Representative Species
Urodela
Salamanders
}
Newts
}
§
Anura
Frogs
}
Toads
}
§
Gymnophiona
Caecilians
}
Apodans
}
§
®
Identifying Features
Lungs used for gas exchange with air
§
Eggs with no shells or membranes
§
Lay eggs in water
§
Larvae usually breathe with gills
§
Adult have paired lungs
§
Cutaneous gas exchange - through the skin
Mucous glands and poison glands
}
§
Only atlas as the cervical vertebra
§
®
□
Amniotes
Identifying Features
Several extraembryonic membranes
Amnion - waterproof chamber to
prevent dessication
Allow egg laying in terrestrial
environments
w
–
}
Temporal fenestraw
}
2 specialized cervical vetebrae
Atlas and axis
–
}
Can have more cervical vertebrae
}
Use lungs to exchange gas
}
§
Sauropsida
Representative Species
Parareptilia
Turtles
–
}
Eureptilia
Lepidosauria
Snake
w
Lizards
w
Legless lizards
w
Tuatara
w
–
Archosauria
Crocodilia
Crocodiles
w
Alligators
w
Gharials
w
Caimans
w
w
Aves
Birds
w
w
–
}
§
Identifying Features
Parareptilia --> anapsid
}
Eureptilia --> diapsid
}
Aves
Endothermic
–
Efficient respiratory system
–
Feathers and wings to adapt for
weight reduction
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Bipedal
–
Beak composed of keratin
–
}
§
®
Mammalia
Representative Species
Monotremes
Platypus
–
echidna
–
}
Metatherias
Opossums
–
Kangaroos
–
}
Eutheria
Most mammals
–
}
§
Identifying Features
Synapsid skull
}
Hair
}
Mammary glands
}
Sebaceous (oil) gkabds
}
Sweat glands
}
Endothermic
}
3 bones in the middle ear
}
Large brains
}
Lower jaw is a single bone called the
dentary
Forms joint with the squamosal
bone
–
}
Monotremes
Lay shelled eggs
–
}
Metatherias
Marsupials
–
Young is born at a very early age
and then crawl into mother's
pouch
–
}
Eutheria
Embryo develops longer period
before birth
–
}
§
®
□
§
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Lab 2 -Phylogeny
February 11, 2018 3:19 AM
Document Summary
Phylogenetic tree - hypothesis of the evolutionary relationships among taxa. Based on shared phenotypic characters and genetic similarities. Character - feature of an organism that can be observed. Important to consider all stages, because may only be present in some. Shared character - 2 or more have same character states via living organisms and fossil examination. Look for position on the tree and mrca. Ancestral (plesiomorphic) - character state evolved a long time ago. Synapomorphy - shared by two or more taxa and mrca. Shared derived characters with the fewest evolutionary changes possible. Located dorsal to the gut, but ventral to cns. Can lateral flexion - bending side to side. No axial compression - getting shorter from end to end. Supports and protects the brain and sensory structures. Separated by myosepta - layers of connective tissue. Arranged metametically (in series from anterior to posterior) Axis - allows side to side head movement.
