Chapter 19 Flashcards
Biologists have developed hypotheses for the evolution of chordate groups using
-Anatomical, molecular, and fossil evidence.
Hagfishes and lampreys
- have a notochard
- lack hinged jaws
- These are fish used to establish a lineage of other fish with heads (craniates)
Jawed vertebrates:
quickly diversified using their paired fins and tail to chase a wide variety of prey.
Jawed vertebrates jaws may have evolved by modifications of skeletal supports of the __________________.
anterior pharyngeal (gil) slits
The remaining gill slits remained as sites of ___________.
Gas exchange
3 lineages of jawed fishes with gills.
- chondrichthyans- sharks and rays
- ray-finned fishes- tuna, trout, and goldfish
- lobe-finned fishes- coelacanths and lungfish
Chondrichthyans
Sharks and rays
ray-finned fishes
tuna, trout, and goldfish
lobe-finned fishes
coelacanths and lungfish
Chondrichthyans have a flexible skeleton made of _______.
Cartiage
Chondrichthyans also have electrosensors on their _____.
head
Chondrichthyans have a ________________ which contains sensory ograns helping these organisms sense a change in temperature or water pressure.
lateral line system
Ray-finned fishes have an internal skeleton reinforced with a hard martrix of _____________.
calcium phosphate
Ray-finned fishes have flattened scales covered with mucus, an ___________ that covers a chamber of gills, and a buoyant ___________.
operculum
swim bladder
Lobe-finned fish
Have muscular pelvic and pectoral fins that are supported by rod-shaped bones
3 lineages of lobe-fins survive:
- coelacanths, living deep in the oceans, were once thought to be extinct.
- lungfishes, which can gulp air into lungs, inhabit stagnant waters in the Southern Hemisphere
- tetrapods, adapted to life on land, include terrestrial vertebrates
Tetrapods are
jawed vertebrates with limbs and feet that can support weight on land
Tetrapods are considered to have evolved from lineage of __________ fish.
Lobe-finned
________ was a key event in vertebrate history, and all subsequent groups are considered descendants of these early land dwellers.
adapting to life on land
Like plants, vertebrates faced obstacles on land for example
- gas exchange
- water conservation
- structural support
- a means of locomotion
- adapting sensory organs that worked well in water but on land
- reproduction
Amphibians
Salamanders, frogs, and caecilians
Amphibians use their moist skin to supplement their lungs for gas exchange, they also (4)
- often have poison glands in their skins
- usually return to standing water to reproduce
- undergo metamorphosis from a larval stage to the adult
Amphibians are
tetrapods
Reptiles are
Amniotes
Reptile (including birds) and mammals are _______
amniotes
In Amniotes the major derived character of this clade is an __________ with four internal membranes.
Amniotic egg
1)In Amniotes The ______ is a fluid-filled sac surrounding the embryo
amnion
2)in Amniotes The ______ contains a rich store of nutrients for the developing embryo
yolk sac
3) In Amniotes the allantois also helps dispose of __________
metabolic waste