Chapter 21 - Biodiversity of Vertebrates Flashcards
What is a vertebrate?
Any animal with a backbone.
What are the major clades (groups) of chordates (4)?
Fishes, amphibians, reptiles (and birds), mammals.
What are 5 predominant
characteristics among vertebrates that we looked at (and their variations)?
- Cartilage skeletons/ bone skeletons;
- Ectothermic (“cold” blooded)/ Endothermic (warm blooded);
- Non-amniotic egg/ amniotic egg/ live birth;
- No parental care/ more parental care;
*Life in water/ life on land
[more primitive/ more evolved]
What are two notable things about vertebrates skeletons?
They have a more extensive skull and backbone; their skeleton grows with them (no shedding exoskeletons).
What are more primitive vertebrate skeletons made of? Which animals have this type of skeleton?
Cartilage and not bone.
The Chondrichthyans (sharks and rays).
What order did these features evolve in: Amniotic egg, jaws, milk, limbs (lobed fins), lungs, legs,
Jaws, lungs, limbs, legs, amniotic egg, milk.
Are hagfish vertebrates? What do they eat and how do they defend themselves?
No, but they are closely related to the lampreys that do have vertebrae.
They are scavengers that make slime!
What are lampreys? What is their relation to vertebrates?
They’re the oldest living lineage of vertebrates. Primarily filter feeders but parasitic in lakes (like the Great Lakes).
When did jawed vertebrae first appear? Did they live in water or on land? Which animals are an example of this?
470 mya.
They still have gills and live in water.
Sharks and rays (chondrichthyans).
What are the first vertebrae made of actual bone?
Ray-finned fishes!
What’s notable about how ray-finned fish breathe and remain buoyant?
They have a covering on their gills used to flow water over the gills and breathe without continuously swimming. A swim bladder helps keep them buoyant
What’s notable about how lobe-finned fish move?
They have modified bones in their muscular pelvic and pectoral fins that may have allowed them to “walk” underwater.
Which types of fish are more evolved?
The ray-finned (majority of fish, all with bones) and lobe-finned fishes.
What are the basic characteristics of fish as a group?
Aquatic, cold-blooded (ectothermic), lay eggs in the water with little to no parental care (except some sharks give live birth).
What type of animal did tetrapods evolve from?
A lineage of lung fish.
What are the first formal tetrapods? What are tetrapods?
Amphibians (frogs, toads, salamanders) but some have “lost their legs”.
Animals with two pairs of limbs.
What are the basic characteristics of amphibians?
Adapted to land but need water to reproduce, highly permeable skin (water loss, breathable), have an aquatic larval stage, cold blooded (ectothermic).
Which animals lay amniotic eggs? What’s an amnion?
Reptiles and birds and even early mammals (monotremes still lay eggs).
A fluid-filled sac surrounding the embryo. The shell is waterproof but still breathable.
What animals are the first group of amniotes? Examples?
Reptiles. Lizards, snakes, turtles,
crocodiles and alligators.
What are the basic characteristics of reptiles?
Internal fertilization, lay amniotic eggs on land, “cold”-blooded, skin covered in scales and keratin to reduce moisture loss.
What are “cold-blooded” (ectothermic) animals?
Doesn’t mean they have cold blood. They do not use their metabolism to produce body heat (which saves energy). Body temp is largely regulated by their surroundings
In what order were mammals, amphibians and reptiles dominant animals on earth?
Amphibians then reptiles then mammals.
How long were reptiles the dominant animals on the planet? What ended this?
200 million years until the 5th mass extinction of the Cretaceous.
What dinosaur lineage is still alive today? How are they different from their reptilian ancestors?
Birds.
They’re homeothermic (warm-blooded), using their metabolism to maintain a constant body temp.
Which dinos did birds evolve from and when?
Therapods (i.e. Archaeopteryx) about 150 mya.
What are the characteristics of Archaeopteryx?
Teeth, wing claws, a long tail with vertebrae, two-legged, feathers. Like a dino/bird hybrid.
What are the basic characteristics of birds?
Amniotic egg layers, feathers not scales, warm-blooded, have fewer offspring that are more cared for by the parents.
What are the basic characteristics of mammals?
Hair, produce milk, warm-blooded, efficient respiratory and circulatory systems, specialized teeth are common, internalized fertilization, usually live birth not eggs.
What are the 3 major lineages of mammals?
Monotremes (egg layers), marsupials (brief gestation), and eutherians (placental mammals).
What were the first mammals to arise? What are their notable characteristics?
Monotremes (platypus and echidnas) Are egg layers.! They also have fur, secrete milk and are warm-blooded.
What are marsupials? What is notable about their reproduction?
Pouched mammals (kangaroos, koalas). Their gestation period is short; highly underdeveloped embryos are born, move to the pouch, and complete their development.
What are Eutherians and their notable characteristics?
“True mammals”.
Placental mammals that give birth to fully developed live young.
When did mammals appear?
When did marsupials and eutherians diverge from a common ancestor?
200 mya.
180 mya.
What are some examples of semi and fully aquatic mammals that moved back into water?
Semi: otters, beavers, and seals.
Fully: dolphins and whales.
What are some key trends in vertebrate evolution (4)?
- Move from water to land
- Cold to warm-blooded
- Increasing development of young within the mother
- Increasing care of young.
