Ch. 34: Origin and Evolution of Vertebrates Flashcards
Chordates have
- Notochord
- Dorsal, hollow nerve cord
Vertebrates
Chordates that have a backbone
Gnathostomes
Vertebrates with jaws
Tetrapods
Gnasthostomes that have limbs
Amniotes
Tetrapods with terrestrially adapted egg
Mammals
Amniotes that have hair and produce milk
Humans
Mammals that have large brain and bipedal locomotion
3 main phyla of Deuterostomes
1) Chordata => A) Cephalochordata and B) Vertebrata and Urachordata
2) Hemichordata => off of Ambulacaria
3) Echinodermata (Ambulacraria) => A) Echinoderms and B) Hemichordates
Types of Echinodermata
- Sea Stars
- Sea Urchin
- outward 5-fold symmetry
Explain how the Hemichordata exhibit characteristics of both Echinodermata and Chordata
- an intermediate group
- Similar to chordates because of pharyngeal gill slits
- Similar to Echinoderms because of their larval morphology and sequence data
3 main phyla of Chordates
1) Cephalochordata (lancelets)
2) Urochordata (tunicates and sea squirts)
3) Vertebrata (Craniata)
Most vertebrates contain
1) Bony cranium
2) Vertebral Column
include fish, amphibians, reptiles, birds, mammals
“Fish” group contains
4 distinct groups of aquatic vertebrates
1) Hagfish
2) Lampreys
3) Cartilaginous fish
4) Lobe-finned fish
Agnatha
without jaws
i.e. Sea Lamprey and Hagfish
have tooth analogs
Osteichthyans (Lung fish)
closest relatives are tetrapods (include amphibians, lizards, turtles, crocodilians, birds, mammals)
Amphibians have
an aquatic larval form and terrestrial adult form
Amniotes
i. e. lizards, snakes, crocodiles, birds, mammals
- have an amniotic egg, permitting movement into dry, terrestrial habitats
Mammals are covered
with hair and feed their young milk from mammary glands
2 synapomorphies that define Echinodermata
1) Radial symmetry (pentamerous)
2) Water Vascular system
Function of a Water Vascular System
- power, move with tube feet
- ampulla that holds water/ attached to tube feet
that can help suction an organism to a particular location
Why are cephalochordates, Urochordates, and Vertebrates all in the same taxon
Taxon: Phylum Chordata
1) Notochord (at some point in their lifetime
2) Pharyngeal Gill pouches (slits)
3) Dorsal Hollow Nerve Tube (Spinal Cord)
4) Post anal tail:
- Rod of vacuolated cells
- Gills or other structures (pharyngeal arches)
- Found above notochord, dorsal
- Muscular
8 trends in vertebrate evolution and how/where each is seen in the phylogenetic tree
1) Vertebrae and Cranium: between Craniates and Vertebrates
2) Jaws: saw with agnatha and gnathostomes
3) Bony Endoskeleton: osteichthyans
4) Tetrapod Limbs: Amphibians
5) Amniotic Egg: Reptiles
6) Feathers and Scales: Reptiles
7) Lactation and fur: Mammals
8) Parental Care: Mammals
draw an amniotic egg and explain its adaptive significance
1) embryo in center
2) amnion with amniotic fluid surrounding embryo
3) yolk sac: provides nutrients
4) allantois: collects waste products (NH3 and uric acid) and exchange membrane
5) Chorion: outer membrane before the shell
6) Shell possible
7) Albumin/ H2O: in between shell and chorion
What do birds and mammals have in common?
major differences?
Common: 4 chambered heart/ feet and legs
Birds:
- feet/legs are scales
- hollow bones
- feathers
- no teeth
Mammals
- Mammary glands
- Hair
- Heterodont dentition
Chondrichthyes
- cartilaginous skeleton
- maintained through life, mineralized and bone secondarily lost
- buccal pumping or ram ventilation depending on species (sharks)
- 2-chambered heart
Osteichthyes
- bony fishes - thin scales
- mineralized skeleton
- swim bladder
- lateral line system
- operculum (or gills)
- 2- chambered heart
Amphibia
- legs
- cutaneous respiration
- lungs - simple, buccal pump
- pulmonary veins
- 3-chambered heart
Reptila
- amniotic egg - not tied to water
- dry skin - thick keratinized epithelium
- thoracic breathing
- negative pressure ventilation
- sencondary/ soft palate
Aves
birds
- Endothermy
- Feathers & Flight
- Hollow bones
- 4-chambered heart
- parabronc
Mammalia
- Hair
- Mammary glands
- Endothermy
- Heterodont dentition
- Nails, hooves, antlers
- carnivore, omnivore, herbivore GI systems
- egg-laying, marsupial, placental
