Biology Chapter 25: Vertebrates Flashcards
What characteristics categorize a chordate?
-Notochord
-Hollow nerve chord
-Pharyngeal slits
-Tail
What 3 groups make up the phylum Chordata?
Vertebrates
Lancelets (Invert.)- small, eel-like animals found in tropical oceans
Tunicates (Invert.)- free-swimming and sessile animals like sea squirts
Notochord
A flexible skeletal support rod embedded in the animal’s back
Hollow nerve chord
Runs along the animal’s back; forms from a section of the ectoderm that rolls up during development
Pharyngeal slits
Slits through the body wall in the pharynx, the gut immediately beyond the mouth; water can enter the mouth and leave the animal through these slits without passing through the entire digestive system
Tail
Extends beyond the anal opening; contains segments of muscle tissue used for movement
Common Vertebrate characteristics
Endoskeleton:
Braincase, vertebrae, bones, gill arches (in fish)
Endoskeleton
An internal skeleton built of bone or cartilage
Class Agnatha
Jawless lampreys, a type of parasitic fish
What is the oldest class of vertebrates?
Agnatha
Chondrichthyes
Cartilaginous fish: skeletons made of cartilage (rays, sharks, and chimeras), jaws
Osteichthyes
Bony fish: Skeletons made of bone; can be ray-finned or lobe-finned, jaws
Amphibia
Live on both water and land: first animal to have 4 limbs
Reptilia
Snakes, lizards, crocodiles, alligators, turtles: retain moisture, amnion
Aves
Birds: Feathers
Mammalia
Hair, mammary glands, three middle ear bones (tigers, lions, bears, etc…)
Also have placenta
Why are tunicates and lancelets considered Chordates?
They have a notochord, it just doesn’t develop into a vertebral column
They also retain pharyngeal slits
Gills
Large sheets of thin frilly tissue filled with capillaries that take in dissolved oxygen from the water and release carbon dioxide
Countercurrent flow
maximizes the amount of oxygen the fish can pull from the water by diffusion (making blood flow in the opposite direction of the current of water entering the gills)
How do gills work?
Muscles in the body wall expand and contract to bring a steady flow of oxygenated water to the gills. The gills take in oxygen from the water and transfer it to the blood circulating throughout the body in one singular loop that flows the opposite direction of the water coming into the gills. Oxygenated blood is dispersed throughout the body and then comes back to the gills where carbon dioxide is release and more oxygen is taken in.
Fish are vertebrates with _____ and ______ ____
gills, paired fins
What are the similarities and differences of gills and lungs?
S: Both take in oxygen and release carbon dioxide
D: Gills only work in water, lungs only work in air
Dorsal fin
Back
Caudal fin
Tail fin
Anal fin
Belly
Pectoral fin
Just behind the head on the side of the body
Pelvic fin
Near the middle front of the belly
List the order of the phylogenetic tree
Agnatha (lampreys)
Chondrichthyes (Cartilaginous fish)
Osteichthyes (bony fish)
Amphibia (frogs, salamanders, first with limbs)
Reptiles (amnion, crocodiles, alligators)
Aves (feathers, birds)
Mammalia (Hair)
How did jaws evolve in fish?
Jaws evolved from the third and fourth gill arches, then attached to the cranium to form the upper jaw, and went on to include more sets of gill arches
Lateral line system
A series of shallow canals on the sides of fish made up of cells that are sensitive to small changes in water movement
operculum
Protective plate that covers the gills of bony fish
Swim bladder
An organ in fish designed to maintain a neutral buoyancy as the fish moves up and down in the water
What adaptations did amphibians develop to live on land?
Large shoulder and hip bones to support weight
Interlocking projecting on vertebrae to support the backbone
Muscular tongue to eat and capture food
Middle ear for hearing out of water
Tetrapod
Animal with four limbs
Amphibian
Live on both water and land
Metamorhposis
The change in form and habits of an animal
Describe metamorphosis in amphibians
Fertilized eggs
Tadpole (tail, no limbs)
Grows limbs
Gills are absorbed and lungs develop
Loses Tail (young frog)
Grows and matures (adult frog)
Amniote
a vertebrate that has a thin, tough, membranous sac that encloses the embryo or the fetus
*many species have gone extinct in periods of mass extinction
Amniotic eggs/cells
A private pool that the mother builds for her embryo; mother produces yolk and white and builds a protective shell that retains moisture as the fertilized egg develops
What is the function of the placenta?
The placenta is a membranous organ that develops in female mammals during pregnancy; partially envelops the fetus and lines the uterine wall.
The placenta carries nutrients from the mother to the embryo and removes metabolic waste from the embryo.
