BIO 2011 Chapter 26: Invertebrates Self Review


Terms in this set (...)

Chordates with a backbone
Vertebrata features
vertebral column, cranium, endoskeleton of cartilage or bone
Vertebrates contain
Cyclostomata, Chondrichthyes, Actinopterygii, Sarcopterygii, Amphibia, Reptillia, Mammalia
Cyclostomata contain
hagfish and lampreys
Marine fish lacking jaws, fins or vertebrae
Secondary loss of vertebral column increased flexibility
Notochord and cartilaginous skull
Essentially blind with a keen sense of smell
Copious amounts of slime
Lack hinged jaw and true appendages
Have a notochord and rudimentary vertebral column

-One of earliest diverging groups of vertebrates
Found in marine and freshwater
Marine lampreys parasitic as adults
Hinged jaws developed from the pharyngeal arches
Evolution modified an existing feature to form the jaw
Some gill arches were lost, some modified
Class Chondrichthyes are
Sharks, skates, rays
Class Chondrichthyes characteristics
Cartilaginous fish
Skeleton of flexible cartilage
Derived character within the Chondrichthyes (not ancestral)
Developmental change prevented ossification of cartilage
Sharks among earliest fish to develop teeth
But teeth are not set into jaw
Denser than water - must keep swimming to maintain buoyancy and breathing
Dual-chambered heart - single circulation
Powerful sense of smell
Lateral line - pressure wave detection
Internal fertilization
Internal fertilization
Oviparous - lay eggs
Ovoviparous - egg retained in female, no placenta
Viviparous - eggs develop in uterus, placenta nourishes young
Osteichthyes contain
Everything but Cyclostomata and Chondrichthyes
Osteichtheys are
bony fish
ray-finned fish
Includes all bony fish except coelocanths and lungfish
Fins supported by thin, bony, flexible rays
lobe-finned fish Actinistia - coelacanths
Dipnoi - lungfish
Tetrapoda (terrestrial vertebrates)
Three features that distinguish from Chondrichthyes
Bony skeleton
Operculum covering gills
Swim bladder for buoyancy
Gnathostomata with Four Limbs
Tetrapoda facts
Transition to land in Devonian involved adaptations for locomotion, reproduction, and to prevent desiccation
Sturdy lobe-finned fishes became animals with four limbs
Vertebral column strengthened, hip and shoulder bones braced against backbone
Relatively simple changes in gene expression, especially Hox genes`
Successfully invaded land but must return to water to reproduce
Buccal pumping to force air into lungs
Skin can absorb oxygen
3 chambered heart
Fertilization external
Larval stages aquatic
Metamorphosis regulated by thyroid
Order Anura
frog and toads
Order Urodela
Order Apoda
Amniota is a
Tetrapoda with a Desiccation-Resistant Egg
Under Amniota
Amniotic egg gave independence from water
Other key innovations from Amniota
Desiccation-resistant skin
Thoracic breathing - negative pressure sucks air in
Water-conserving kidneys - concentrate waste prior to elimination
Internal fertilization
Traditional classification has three living amniotes
reptiles, birds and mammals
Birds are now considered part of reptilian lineage
Class Testudines
Turtles, tortoises and terrapins
Virtually unchanged for 200 million years
Hard protective shell
In most, vertebrae and ribs fused to shell
Lack teeth but have sharp beak
Class Squamata
Lizards and snakes
Kinetic skull with extremely mobile joints
Lizards have moveable eyelids and external ears while snakes do not
Class Crocodilia
Crocodiles and alligators
Essentially unchanged for 200 million years
4 chambered heart
Teeth in sockets
Care for young
Archaeopteryx lithographica
A transitional species with both dinosaur features and bird features like wings and feathers
Related to therapods, group of saurischian dinosaurs
Class Aves have Four features unique to birds (for flight):
Feathers - modified scales keep birds warm and enable flight
Air sacs - very efficient breathing
Reduction of organs - single ovary, no urinary bladder
Lightweight bones - thin, hollow, honeycombed
Sternum to anchor flight muscles, no teeth
Birds also have
Warm body temperature
Double circulation with 4 chambered heart
Acute vision
Most carnivores
Eggs brooded
Complex courtship
Milk-Producing Amniotes
Mammalia facts
Evolved from amniote ancestors earlier than birds
Appeared about 225 mya
After dinosaur extinction mammals flourished
Range of sizes and body forms unmatched
Distinguishing characteristics of mammals
Mammary glands secrete milk
All mammals have hair (more or less)
Only vertebrates with specialized teeth
Enlarged skull
enlarged skull
Brain enlarged in large skull
Single lower jaw bone
3 inner ear bones (ossicles)
External ears (pinnae)
Subclass Prototheria
- Monotremes
Platypus and echidna lay eggs, lack placenta, poorly developed nipples
Subclass Theria
Clade Metatheria - Marsupials
7 orders
Once widespread, now confined mostly to Australia
Opossum found in North America
Very undeveloped young must make it to marsupium to finish development
Subclass Theria
- Clade Eutheria
Placental mammals
Long-lived complex placenta
Prolonged gestation
Primarily tree-dwelling species
Evolved about 85 mya
Defining characteristics
of primates
Grasping hands with opposable thumbs
Large brain
Some digits have flat nails (not claws)
Binocular vision
Complex social behavior, well-developed parental care