Phylogeny Flashcards
Location of endostyle
Ventral side of pharynx
Distinguishing features of parareptilia
- SHELL
- anapsid skull
Who are the sarcopterygiians?
Fleshy-finned fish (osteichthyes)
Describe adult form of urochordate
Sessile, filter feeder, has pharyngeal slits, endostyle, incurrent & excurrent siphons, atrium, digestive system
What does the muscular pharyngeal pump of vertebrates replace in urochordates and cephalochordates?
Cilia in pharynx
Synapomorphy of eureptilia
diapsid skull (2 pairs of temporal fenestrae)
How can amniotes be identified/differentiated?
By temporal fenestrae
What is eureptilia divided up into?
Lepidosauria, Archosauria
Evolutionary advantages of cranium
Protects brain & sensory organs, allowing the brain to grow bigger and better -> Allows more complex & maneuverable body
Distinguishing features of Monotremes
- Embryos develop in leathery-shelled eggs (vs. other mammals: live birth)
- Cloaca (shared opening for urinary, excretory, reproductive releases)
Describe pharyngeal slits
Slits in chamber posterior to mouth, present during at least some point of development of chordates (lost in most adult species, kept under gills in fish)
Polyphyletic group (def)
taxa not descended from an immediate common ancestor
Teleostei refers to…
A diverse subgroup of Actinopterygii
Describe anatomy of notochord
Cell core, fibrous sheath, ventral to hollow nerve cord
Function of endostyle
Produce mucus, process iodine (homologous to vertebrate thyroid - processes iodine, produces HORMONES)
Cyclostomes refers to…
Agnathans (cyclo-: round, -stomes: mouth -> round-mouthed)
What’s special about Myxinoidean body fluids?
Isosmotic w/sea water (v. salty)
Phylogeny (def)
Evolutionary history of any group of organisms
Secondary loss (def)
Loss of a character shared with an ancestor
Pleisiomorphy (def)
Ancestral (inherited) character; relative to taxon under consideration
5 shared traits of chordates
- dorsal hollow nerve cord
- endostyle/thyroid
- pharyngeal slits
- postanal tail
- notochord
Advantages of muscular pharyngeal pump over cilia
- higher volume flow rate -> eat more, grow bigger
- more damage-resistant
- move large particles against a force
- cilia lining the pharynx limits size
Synapomorphy (def)
Derived character shared by 2+ taxa; relative to taxa under consideration
Advantages of jaws & paired fins together
- Allow hunting/more food sources -> can increase metabolic rate & activity
Describe cranium as vertebrate synapomorphy: embryonic origin, function
from neural crest cells & mesenchyme; protects brain & sensory organs, provides structural support, needed for jaws in jawed species
Reason for motile urochordate larvae
Can disperse to find new living sites (not for finding food b/c don’t really eat during the <1 day larval stage)
Traits of amphibia
- aquatic larvae metamorphose to (semi-)terrestrial adults
- thin, scaleless, mucus-covered skin for cutaneous respiration
- anamniotic eggs: must be kept moist or will dessicate
Synapomorphies of Aves
Feathers
Air sacs of respiratory system (incl. hollow bones)
Endothermy
Who are the actinopterygiians?
The ray-finned fish (osteichthyes)
Location of dorsal hollow nerve cord
Dorsal to digestive tract
Teleostomi refers to…
Osteichthyes & Tetrapoda
How do you determine if a character is a synapomorphy or arose from convergent evolution?
Examine intervening species, other members of the taxa
How do chondrichthyans maintain their buoyancy?
Oily liver (still slightly more dense than water, so sink to bottom or keep swimming w/heterocercal tail)
Who are the metatherians?
Marsupials
2 defining features of Agnathans
- no jaw (cyclostome)
- lack bone
Monophyletic group (def)
1 ancestor & ALL of its descendents
What is chondrichthyes divided up into?
Elasmobranchii (sharks, rays, skates)
Holocephali (ratfish)
Who are the monotremes?
Echidna, platypus
How do cephalochordates use the pharyngeal slits?
For filter feeding (food sticks on mucus (from endostyle) on pharyngeal bars, moved to digestive tract by cilia)
Typical function of post-anal tail
Locomotion (particularly by lateral undulation)
Which of the 5 main chordate characteristics are maintained by adult urochordates?
Endostyle, pharyngeal slits (others lost in drastic metamorphosis)
Advantages of paired pelvic & pectoral fins
Better stability & steering -> better maneuverability (-> can move up water column to new food sources)
Synapomorphies of vertebrates?
Vertebral column, cranium, muscular pharyngeal pump (also neural crest cells)
Synapomorphies of amniota
- Extra-embryonic membranes: amnion, chorion, allantois (& yolk sac)
- Epidermal scales
Defining features of Myxinoidea?
- NO vertebrae
- notochord (kept for lateral undulation)
- 1 loop of vestibular apparatus
Synapomorphies of synapsida
- Endothermy
- Synapsid skull
- Hair
- Mammary glands
- 3 middle ear bones & 1 lower jaw bone
Location of notochord
Dorsal to digestive tract, ventral to dorsal hollow nerve cord
Synapomorphy of teleostomi
Adjustable gas bladder (swim bladder for buoyancy or lungs for gas exchange)
What data is used to determine the relation of organisms?
Genetics Shared (homologous) characters of living & fossil organisms
Distinguishing feature of actinopterygii
Ray-fins
Function of notochord
Provide longitudinal axis structural support, promote lateral undulation
What is Lepidosauria divided into?
Squamata, Sphenodonta
Advantage of extra-embryonic membranes in calcareous or leathery shell
Prevent dessication -> can lay eggs on land
3 synapomorphies of gnathostomes
- bone
- jaws
- paired pelvic and pectoral fins w/ supportive bony/cartilaginous girdles, muscles
Most recent common ancestor (def)
Latest interbreeding population (NOT an individual)
Advantages of legs, as tetrapod synapomorphy
Good for bearing weight on land
Teleosti (def)
diverse subgroup of Actinopterygii
Describe vertebral column as vertebrate synapomorphy
Series of bones/cartilages that allow movement, define body axis, protect dorsal nerve cord
Embryonic origin of dorsal hollow nerve cord
Ectoderm (neural plate cells)
What is a synapomorphy of metatherians? Any other distinguishing characters?
Young born early in development, grow in marsupium (maternal abdominal pouch)
Typical form of post-anal tail
Posterior to anus; contains notochord and myomeres
Apomophy (def)
Derived character; relative to taxon under consideration
What is archosauria divided up into?
Aves, Crocodilia
Which of the 5 main chordate characteristics are retained in adult cephalochordates?
All (no major metamorphosis)
Embryonic origin of notochord, role in adult
Mesoderm; usually replaced during development (lesser role in adult)
Sarcopterygii synapomorphy (advantages?)
fleshy fins (better for stability in challenging environments, could be used to bear weight)
Clade (def)
1 ancestor & ALL of its descendents (monophyletic group)
What is synapsida divided up into?
Montrema, then Eutheria & Metatheria
How do urochordates use their pharyngeal slits?
For filter feeding (food sticks on mucus (from endostyle) on pharyngeal bars, moved to digestive tract by cilia)
Tetrapoda refers to…
Amniotes (Sauropsids & Synapsids) & Anamniotes (Amphibia)
Synapomorphy of tetrapods
Legs (chiridium: muscular appendages with well-defined joints and digits)
Paraphyletic group (def)
1 ancestor but NOT all of its descendants
Synapsida (def)
Mammals
Advantages of jaws
good for biting/eating wider variety of food, free pharyngeal bars for gas exchange
Synapomorphy of eutherians
Chorioallantoic placenta (chorion & allantois)
