and diversity (learning outline) 1.distinguishing features
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Animal Evolution: Chordate and Vertebrate Evolution and Diversity (Learning Outline)
1. Distinguishing features of the phylum Chordata and
representative organisms. 2. Highlights of evolutionary steps of aquatic chordates
and vertebrate animals 3. Highlights of evolutionary steps of land vertebrates. 4. Place chordates in order of appearance on earth. 5. For organisms covered in class or lab, place each in
its classification grouping , relation to others, and know their major evolutionary features.
Sac Body Plan
Tube within Tube
Organ Systems (Coelom)
Level of Organization Multicellular
Segmentation
Spon
ges
Cni
daria
ns
Flat
wor
ms
Rou
nd w
orm
s
Mol
lusc
s
Anne
lids
Radial Symmetry Bilateral Symmetry
No Body Cavity (No coelom)
Body Cavity (Pseudocoelom)
Mouth from First Embryonic
Opening
Mouth from Second Embryonic
Opening
Arth
ropo
ds
Echi
node
rms
Cho
rdat
es
Phyla
Phylum Chordata, is distinguished by four features
• A dorsal hollow nerve cord • A stiff notochord* • Pharyngeal slits • A muscular post-anal tail
Includes invertebrates and vertebrates
(*) A long flexible rod of cells that supports the body of chordates and vertebrate embryos and is in effect a primitive backbone
Chordates Craniates
Vertebrates Jawed vertebrates
Tetrapods Amniotes
Milk
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws
Vertebral column
Head
Brain
Ancestral chordate
Tuni
cate
s
Lanc
elet
s
Hag
fishe
s
Lam
prey
s
Shar
ks, r
ays
Ray
-finn
ed fi
shes
Lobe
-fins
Amph
ibia
ns
Rep
tiles
Mam
mal
s
Chordates Invertebrates
Tunicates - Sea Squirts • Fossil record- appeared in early Cambrian
Period • Marine invertebrates with pharyngeal slits for
suspension feeding
http://www.youtube.com/watch?v=n8ARUKWPJAE
Excurrent siphon
Adult (about 3 cm high)
Mouth
Pharyngeal slits
Dorsal, hollow nerve cord
Larva
Lancelets • Small eel-like organisms that live in the ocean • Filter feeders and use cilia to filter food out of the
water. • Anchor their tails in the sand and let the water wash
over their mouths. • Have a nerve cord, brain but no vertebrae
• http://www.youtube.com/watch?v=GPnPXsanclY
Head
Mouth
Pharynx Pharyngeal slits Digestive tract
Water exit
Segmental muscles Anus
Post-anal tail
Dorsal, hollow nerve cord
Notochord
Jawless fish- Lamprey • Vertebrates • Adult has toothed, funnel-like sucking mouth • No jaws • No paired fins • Skeleton made of cartilage http://www.youtube.com/watch?v=9JQ6oHjpeqU
Sharks and Rays • Jaws • Flexible skeleton made of car tilage • Paired fins • Uncovered gills • Internal fertilization
Bony fishes: sub groups • ray-finned fishes • lobe-finned fishes
Bony Fishes- ray-finned fishes (most fish) - Skeleton reinforced with a hard matrix of
calcium phosphate - Operculi that move water over the gills - A buoyant air-filled swim bladder
Gills
Bony skeleton Dorsal fin
Anal fin Swim bladder
Heart Pectoral fin Operculum
Pelvic fin
Rainbow trout, a ray-fin
• Eels are bony fish that have a muscular, snake-like body
Bony Fishes- Lobe-finned fishes • Muscular fins supported by bones
Tetrapod
Amphibians • Tetrapods—two pairs of limbs allowing
movement on land • Most reproduce in water • External Fertilization and embryos and larval
development take place in water • Examples: Salamanders, frogs and toads
Amniotes • Tetrapod vertebrates • Adapted to survive in a terrestrial
environment. • Internal fertilization • Have an amnion during the embryologic
stage • Egg-laying reptiles and birds and some
early mammals • Internal gestation and milk (Mammals)
Reptiles are amniotes—tetrapods with a terrestrially adapted egg
Terrestrial adaptations of reptiles include Waterproof scales Internal fertilization shelled, amniotic egg
Dinosaurs, the most diverse reptiles to inhabit land – Some of the largest animals ever to inhabit land – May have been endothermic, producing their own body
heat – Living reptiles other than birds are ectothermic
Birds • wings, feathers, and endothermic metabolism • flight adaptations • Evolved from a small, two-legged ectothermic dinosaurs.
Wing claw (like dinosaur) Teeth
(like dinosaur)
Feathers Long tail with many vertebrae (like dinosaur)
Mammals are endothermic amniotes with - Hair for temperature insulation - Internal fertilization - Mammary glands for milk production
Two groups of mammals 1. Marsupials- Kangaroos 2. Eutherians, placental mammals
The embryos of marsupials are: - nurtured within the uterus - leave the uterus before completing development - complete development attached to the mother’s nipple, usually inside a pouch Kangaroo Birth https://www.youtube.com/watch?v=PmJkn9dJDQ8
Eutherians, placental mammals, complete development before birth
Birth of an elephant https://www.youtube.com/watch?v=1IDRIdE05ko