Animal Flashcard Activity (Chordates)
Biological Principles II
1. We have previously divided the animal flashcards as shown below:
METAZOA
(Kingdom Animalia)
EUMETAZOA
(cells organized into true tissues)
Diploblasts/Radiates
Sponges
12
62,63,65,67,68,69
70,71,72,73,74,75,76,77,79
80,81,82,83,84,85,86,88,89
90,91,92,93,95,96,97,98,99
101,102,103,104,105,106,
107,108,109,110
Cnidarians:
66,94,100
64,87
tiS Stiff)
Triploblasts/Bilaterians
Ctenophores:
78
The bilaterians are broken
down into three clades based
on molecular data.
68
67,69
73,76,77 QpUfJgJffffe
81,82
97
101
Deuterostomes
Ecdysozoans
Lophotrochozoans
83,84,85,86,89
Mollusc/
(ie«*Wfc2,63,65
Ji.uu.Jt70,71,72,74,75,79
^irso! 88
90,91,92,93,95,96,98,99
102,103,105,106,107,108,109,110
There are two major
deuterostome phyla.
Echinoderms
(Sea srf*")
Chordates
12
62,63,65
71,72,74,75,79
80,88
91,92,93,95,96,98,99
102,103,105,106,107,108,109,110
r
METAZOA > EUMETAZOA > BILATERIA > CHORDATA
2. All chordates, at some point in their lives,
possess four shared derived characters:
Dorsal,
hollow
Muscle
segments
nerve cord
0 a hollow, dorsal nerve cord
gf a notochord (a firm cartilaginous rod
that is used as the site of muscle
attachment for swimming)
(yj a series of subdivided pouches behind
the mouth called pharyngeal clefts that
can develop into slits that become open
to the outside environment
Mouth
Anus
Muscular,
post-anal tail
Pharyngeal
slits or clefts
0 a muscular post-anal tail
3. Separate out #93 and #91. These represent the two most basal groups of chordates:
La
nee
lets
Tunicates
(seASwH*® 91
Named for their bladelike shape
Retain all four chordate traits
throughout their lives
• Only possess all four chordate
traits as larvae
• Undergo a radical
metamorphosis and become
sessile
4. The remaining chordates will begin to dramatically modify their body plans, resulting in
increasing leaps of complexity.
CRITICAL INNOVATION #1: Craniation
5. The first critical innovation observed in the chordate lineage is the appearance of a head or
cranium.
0" Craniates possess a brain at one end of their nerve cord.
gf This brain is encased in a skull and is connected to complex sense organs.
0 Their brains allow craniates to coordinate more complex movement and feeding patterns.
6. Separate out flashcard #96.
Hagfish:
• Hagfish are the least derived of the living
craniates.
• They have a skull made of cartilage, but lack
jaws and vertebrae.
• They use their notochord to swim in a
snakelike fashion.
• Live mostly as bottom-dwellers where they
scavenge.
CRITICAL INNOVATION #2: Vertebral Columns (Backbones)
7. The next innovation was the appearance of a backbone, called a vertebral column. Chordates
with a backbone are called vertebrates.
0 Very primitive vertebrates have greatly reduced vertebrae that resemble tiny prongs of
cartilage.
gf In most vertebrates, however, the vertebral column is composed of bone and encases the
dorsal nerve cord.
8. Separate out flashcard #102.
Lampreys:
• Lampreys are the least derived of the living
vertebrates.
• Their skeletons are made of cartilage.
• They are mostly parasitic, using their sucker
like mouths to attach to the sides offish.
lljtfA)l£s; fishes'*
CRITICAL INNOVATION #3: Jaws
9. Most vertebrates possess jaws. We refer to these jawed animals^ts gnathostomes. 3
0" Jaws are hinged mouthparts that, along with teeth, help animals tear food into pieces for
ingestion. Prior to the evolution of jaws, animals were forced to eat materials smaller than
their mouths.
g[ Most biologists agree that jaws evolved from bones that supported pharyngeal slits (or
gill slits) directly behind the head. These thin bony struts became thicker and formed jaw
bones.
r
(Vf In addition to jaws, gnathostomes hav/enlarged brainsjy^fenhanced senses^ncluding a
sense organ called a lateral line system, ihe lateral line system torms rowsalong either
s i d e o f t h e b o d y t h a t c a n s e n s e v i b r a t i o n s i n t h e w a t e r. 1
\ah**A IW. s^-teiw- cJe+e^ n>M-m;
10. Separate out flashcards #99 and #103.
Sharks
Rays
Cartilaginous fish (chondrichthvans):
• These fish have skeletons composed
primarily of cartilage.
• Areas of their skeletons have begun the
process of mineralization (which will result
in the fully-mineralized skeletons that
humans have).
• Most have streamlined bodies for swift
swimming, but cannot maneuver well.
• These fish are not naturally buoyant; they
will sink if they stop moving.
Separate out flashcards #74 and #105.
Ray-finned fish (osteichthyans):
• These fish have fins that are supported by thin
bones called rays.
• Most of the fish with which we are familiar are
ray-finned, such as trout, salmon, cod, goldfish,
bass, and swordfish.
• Their skeletons ar^completely mineralized/^
• They possess a swim bladder that makes them
clovnjlsli
buoyant, so they can stop swimming without
sinking.
11. The remaining "fish" fall into three lineages.
0 In all three of these lineages, the fins evolved from thin flaps of tissue with tiny bones into
thick, fleshy, muscular fins supported with more substantial bones.
(vj These animals are referred to a^Qobe-finned fislVT)
0" Lobe-finned fish use their muscular fins to paddle along the bottom, occasionally making
their way out onto dry land.
gf One of these lineages—the tetrapods—became terrestrial and evolved into the vast array
of land-dwelling vertebrates.
r
12. Separate your flashcards into the three lineages of "lobe-finned fish."
Coelacanth
Tetrapods
Lungfish
12
62,65
71,72,75,79
88
92,95,98
106,107,108,109,110
CRITICAL INNOVATION #4: Tetrapod Body Plan
13. Becoming terrestrial for the tetrapods brought with it a series of challenges their ancestors
had not encountered in the water:
gf they evolved limbs with feet that could support them on land
0 their senses had to adapt
r
0 they had to evolve structures that allowed them to perform gas exchange with air (rather
than in water)
14. The least derived of the terrestrial tetrapods are the amphibians. Their name refers to their
dual life: a larval stage spent in the water and an adult stage spent on land.
15. Adults must return to the water to reproduce. In fact, amphibians stay close to moisture
throughout their lives; they have relatively thin skin, so they are always at risk of drying out.
16. Separate out your amphibian flashcards, as shown below:
Mali- s-b$r r* rerr*sw*i
Ua\h Art. sWI reztrrdtj ft> m#n* U.**s:
-TVvet, kccA A-zP fV repiWu-cTic^ 5
CRITICAL INNOVATION #5: Amniotic Eggs
17. In order for tetrapods to exploit new terrestrial habitats, they had to become less dependent
on water. As a result, two new innovations appeared:
gftough skin(r)iade out of the protein keratin) that prevented desiccation (drying out)
gf an egg that contained fluid inside of it called amniotic fluid
18. The amniotic egg, in particular, is a noticeable improvement on amphibians in that it meant
that reproduction could occur away from water.
19. There are two groups of animals that produce amniotic eggs. They are:
Mammals
Reptiles
12
62
71
88
92
109
72,75,79
95,98
106,108,110
20. Separate the reptile flashcards as shown below:
Other reptiles:
• These were the first truly terrestrial tetrapods.
Birds:
• Birds are highly derived reptiles and are
• They have a thick, leathery skin made of keratin
that prevents them from drying out.
• In addition, they can lay their amniotic eggs on
hypothesized to be the descendants of the
dinosaurs.
• Their keratin scales have evolved into feathers.
dry ground, away from water.
e^fp+h-eKMfc (coldblccxl&Lj
• Birds evolved flight independently of insects and
bats.
• Birds are endothermic (warmblooded), meaning
that they regulate their body temperatures.
dittos
CRITICAL INNOVATION #6: Mammals
21. Arguably, the most derived of the chordates are the mammals. Mammals have four basic
characteristics:
0 they possess hair and subcutaneous fat that allows them to retain heat
gf they produce milk for their young with mammary glands
gf they have a muscle called a diaphragm that they use to draw air into their bodies
0 they a^endothermic (warmblooded), but they evolved this independently of the birds
22. Separate your flashcards into the three groups of mammals, as shown below:
t Monotremes:
• This is the only group of
mammals that lays eggs.
• Includes the platypus (#108) and
the echidna.
• Today, they are only indigenous to
Australia and New Guinea.
Marsupials:
• These mammals give birth to very
premature young and then raise
them in external pouches.
• Includes koalas (#95), kangaroos,
possums, wombats, and wallabies.
Eutherians (placental mammals):
• Includes most mammals.
• These mammals use a placenta to deliver nutrients
to developing young within the mother's body.
onll*-
efe#k4*f~72