Lesson 10: Kingdom Animalia Phylum Chordata

Question 1

Phylum Chordata

Answer 1

-most organisms are vertebrates. They have a bony skeleton and backbone.
-however there are two groups of invertebrates included in the phylum chordata because they share the 3 key features of all chordate animals.
-4 subphyla

Question 2

Key features of phylum chordata

Answer 2

1. A dorsal nerve cord which branches to all parts of the body.
2. A notochord (rod of cartilage), which runs along the dorsal length of the dorsal length of the body.
   —> occurs only in the embryo in vertebrates (a backbone of cartilage or bones replaces the notochord)
3. Gill slits in the pharynx(throat).
   —> in terrestrial vertebrates the hills slits occur only in the embryo

Question 3

Subphylum urochordata

Answer 3

-tunicates (sea squirts)
-invertebrates

Question 4

subphylum cephalochordata

Answer 4

-lancelets
-invertebrates

Question 5

subphylum agnatha

Answer 5

-jawless fishes such as hagfish and lampreys
-the oldest group of vertebrates
-only about 60 species exist today
-smooth, tube-shaped fishes grow up to one metre long.
-scavengers or parasites

Question 6

Subphylum gnathostomata

Answer 6

-jawed chordates
-vertebrates
-6 classes
-> class chondrichthyes
-> class osteichthyes
->class amphibia
->class reptilia
->class aves
->class mammalia

Question 7

Class chondrichthyes

Answer 7

-there are about 850 species of sharks, rays, and skates
-have a skeleton of cartilage rather than bone and 5-7 hill slits (lack the gill covers that are characteristic of bony fish)

Question 8

Class osteichthyes

Answer 8

-abt 20000 known species of bony fish.
-have a skeleton of bone
-most of the fish species are called ray-finned fishes (have scales formed from bone).
-the ancestors of the first land—living vertebrates were the love-finned fishes (fleshy fins supported by limb like bones)
—> there are 6 species of lungfish and one species of coelacanth in existence today

Question 9

class amphibia

Answer 9

-means “dual-life” in reference to the fact that the 4000 species of the class amphibia start life as gill breathers but spend their adult life as lung breathers
-depend on external sources of heat to regulate body temperature
-have a 3 chambered heart, smooth scale-less skin and eyelids
-limbs are adapted for walking on land can produce sound from their larynx

Question 10

Class reptilia

Answer 10

-most of the 6000 species of the class reptilia live in deserts and tropical areas
-have better developed lungs than amphibians and a rib cage to protect them
-have a thick scaly skin made from keratin (also a key component of feathers, fingernails and hair)

Question 11

Class Aves

Answer 11

-the key feature that distinguishes the 9000 species of the class Aves is feathers
-feathers are a modified form of reptile scales. They also share body shape, leg scales, clawed toes and shell covered eggs.
-most structural features are related to flight
&raquo_space; hollow bones
&raquo_space; system of air sacs in their bones allow them to move air in only one direction

Question 12

Class mammalia

Answer 12

-distinguished from other vertebrates by the presence of hair and milk producing mammary glands.
—> most give birth to live young
—> most live on land (exceptions include dolphins and whales)
—> have lungs and a four chambered heart