Vertebrates (1) Flashcards
How long have vertebrates been evolving?
Vertebrates have been evolving for half a billion years.
Describe the first vertebrates.
The first vertebrates were small, slender aquatic creatures
What are the features of hagfish and lampreys?
Hagfishes and lampreys:-
-have rudimentary vertebrae,
-have a notochord for the body’s main support
-Lack hinged jaws.
What type of animal are hagfish and what is their antipredator defense?
Hagfishes are scavengers that produce slime as an antipredator defense.
What type of animal are lampreys and what is the special morphological character they possess?
Many species of lamprey adults are parasites that penetrate the sides of fishes with their rasping tongues.
How did jaws evolve ?
Jaws may have evolved by modifications of skeletal supports of the anterior pharyngeal (gill) slits.
The remaining gill slits remained as sites of gas exchange
Three lineages of jawed vertebrates with gills and paired fins are commonly called _______
Three lineages of jawed vertebrates with gills and paired fins are commonly called fishes
How are fishes classified?
- Chondrichthyans, sharks, and rays, have flexible skeleton made primarily of cartilage,
- Ray-finned fishes, for example, tuna, trout, and goldfish, have a skeleton made of bone
- Lobe-finned fishes, coelacanths, and lungfishes, have a series of rod-shaped bones in their muscular pectoral and pelvic fins.
What animal did lobe-finned fishes give rise to?
Lobe-finned fishes gave rise to tetrapods.
Who were the first tetrapods to colonize land?
Amphibians.
What are the features of amphibians?
-use their moist skins to supplement their lungs for gas exchange
-often have poison glands in their skins
-usually lay their eggs in water
-undergo metamorphosis from a larval stage to the adult form
Reptiles, birds, and mammals are amniotes, what do amniotes entail?
Tetrapods with a terrestrially adapted egg.
The major derived character of this clade is an amniotic egg, with four internal membranes.
What are the characteristics of reptiles?
-Have a skin covered with scales and waterproofed with keratin
-Obtain most of their oxygen using lungs
- Ectothermic, absorbing external heat rather than generating much of their own
What are characteristics of birds?
-Birds are endothermic, using heat generated by metabolism to maintain a warm, steady body temperature.
-Birds typically display very complex behaviors, particularly during breeding season.
What animal did birds evolve from?
Birds evolved from a lineage of small, two-legged dinosaurs called theropods.
What is the oldest bird known?
Archaeopteryx is the oldest, most primitive known bird (150 million years old
What were the functions of early feathers?
Early feathers may have functioned in:-
-insulation
-courtship displays
What are the features of mammals?
-endothermic amniotes
-have hair, which insulates their bodies
-mammary glands, which produce milk.
-Mammals have efficient respiratory and circulatory systems that support their high rate of metabolism.
What are monotremes?
Monotremes are egg-laying mammals
What are the embryos of marsupials and eutherians nurtured by?
The embryos of marsupials and eutherians are nurtured by a placenta, in which nutrients from the mother’s blood diffuse into the embryo’s blood.
Differentiate between marsupials and eutherians.
Marsupials have a brief gestation and give birth to tiny, embryonic offspring that complete development while attached to the mother’s nipples.
Eutherians (placental mammals) bear fully developed live young
