chapter 15.6 Flashcards
are chordata deuterostomes or protostomes?
all chordata are deutorostomes
do chordata have a notochord?
yes, all chordata have a notochord
what is the closest relative of chordata?
echinodermata are chordata’s closest relative
how are chordata and echinodermata alike?
they both have a unique embryo development
when did the common ancestor of chordata and echinodermata live?
around 600-700 million years ago
what do the embryos of chordata have?
nerve cords, notochords, gill structures, and post-anal tails
what are nerve cords?
hollow cords found along the dorsal in the upper part of the body
what are notochords?
flexible rods between digestive tract and nerve cords
what is the purpose of notochords?
for support and muscle flexibility attachments
what are gill structures?
gill splits in pharynx just behind mouth
what is the purpose of gill structures?
for filter feeding, and gas exchange
what is post-anus tail?
tail posterior to anus
what is another name for gill structures?
pharynx splits
what are the two main groups of chordata?
invertebrates and vertebrates
what are the two main groups of invertebrate chordata?
tunicates (urochordata) and lancelets (cephalochordata)
how many species of tunicates are there? are they marine or on land?
2,000, marine
what are tunicates shaped like?
like bags
what kind of feeders are tunicates?
they are filter feeders
are the shared characteristics of chordata present in tunicates as embryos?
yes
are the shared characteristics of chordata present in tunicates as adults?
no, they dissapear in adulthood
how many species of lancelets are there? are they marine or on land?
25, they are marine bottom dwellers
are lancelets segmented or non-segmented?
segmented
what do lancelets use to swim?
their segmented muscles and notochords
do lancelets have open or closed circulatory systems?
closed circulatory systems
where are the lancelets eyespots located?
near the anterior end
what kind of feeders are lancelets?
filter feeders
where are the lancelets filter feeders located?
through the gills
do adult lancelet embryos have the shared chordata characteristics?
yes
tell us about the water passage through lancelets
water enters through the filter feeders in the gills, then collects in the atrium, then exits through atriospore
did vertebrates evolve after invertebrates?
after!
what is the most important thing in vertebrates?
vertebrates! er backbones
what are the two classes of living jawless fish?
hagfishes and lampreys
what is the hagfishes nickname?
slimeballs of the sea
do hagfishes have notochords?
yes
do hagfishes have any cartilage elements?
yes hagfishes have a few cartilage elements
what kind of braincase to hagfishes have?
they have a rudimentary braincase
is the nerve cord of hagfishes protected?
yes, by skeletal elements
how many species of hagfishes are there?
20 species
what do hagfishes eat?
they feed on worms and scavenge
how many species of lampreys are there?
40
tell us about the notochord of lampreys…
it has a cartilaginous structure
what are the nerve chords of lampreys protected by?
by cartilage segments
do lampreys live in fresh or sea water?
there are fresh and sea water species
where do lampreys spawn?
in fresh water
when was the origin of jaws?
425 million years ago
where did jaws evolve from?
they evolved from gill-supporting structures
what do jaws allow?
they allow a wider range of food sources
jawed fish also have what?
pectoral and pelvic fins
how many species of cartilaginous fish are there?
625 marine species
what is the skeleton of cartilaginous fish made of?
it is made of cartilage
what are some of the acute senses of cartilaginous fish?
smell and electro sensors
what kind of feeders are cartilaginous fish?
mostly predators, and a few filter feeders
how many chambers does the heart of cartilaginous fish have?
two chambers
how do cartilaginous fish reproduce?
internal fertilization
what does ovoviviparious mean?
eggs develop within the mother
what is the most diverse vertebrate group?
bony fish
how many species are there in bony fish?
30,000 species
where are bony fish found?
in every watery habitat
what are fins?
webs of skin supported by bony spines
what is the skeleton of bony fish made of?
bones duh
what are the classes of lobe-finned fish?
coelathans and lungfishes
lobe-finned fish have skeletons made of?
bones
the fleshy fins of lobe-finned fish have what?
rod-shaped bones, surrounded by muscles
how many species of coelathans are there?
2
how many species of lungfishes are there?
6
the ancestors of lobe-finned fish led to what?
amphibians
how many chambers are in the heart of amphibians?
three
amphibians were abundant during what period?
carboniferous period
how many species of amphibians are there?
6,770
amphibians have deformities because of?
chemicals
why is the population of amphibians declining?
habitat destruction, environmental degradation, pesticides, and parasitic diseases
what came after amphibians?
amniotes
what are amniotes?
animals that lay eggs on land
why do amniotic eggs have shells?
to protect the embryo from drying out
what is an amnion?
membrane with fluid for protection
what is a yolk sac?
food for amniotic eggs
what does the allantois do?
collects food
what is the albuminum?
egg white
what is the chorion?
membrane under the shell
the following are amniotes:
reptiles, birds, and mammals
amniotes led to two lines, what are they?
synapsids and reptiles
synapsids led to what?
mammals
what are some of the classes of reptiles?
anapsids, synapsids, and diapsids
how many holes are there in the skull of anapsids?
none
how many holes are there in the skull of synapsids?
one
how many holes are there in the skull of diapsids?
two
when did reptiles develop?
during the carboniferous period
when were reptiles abundant?
during the mesozoic
