bio lab 6: chordates Flashcards
(80 cards)
1
Q
when did the first members of Phylum Chordata evolve in Cambrian seas
A
500 million years ago
2
Q
what are the 4 traits that all chordates have
A
- notochord,
- dorsal, hollow nerve cord,
3.pharyngeal slits or clefts - muscular, post-anal tail
3
Q
describe the notochord and what is differentiates into
A
flexible rodlike structure of mesodermal cells
become part of vertebral column
4
Q
describe the dorsal, hollow nerve cord and what it develops into
A
hollow tube of nervous tissue located along the dorsal side of body
develops into central nervous system (brain and spinal cord)
5
Q
describe pharyngeal slits/clefts and what it develops into
A
openings between the pharynx / through and the outside
differentiate into the external ear canal; formation of neck and throat structures
6
Q
describe the post anal tail and what it differentiates into
A
posterior elongation of body
tail / vestigial structure - in humans/ apes only found in embryonic development
7
Q
what are the 3 subphyla that phylum Chordata is generally subdivided into?
A
Subphylum Urochordata (Tunicates) – invertebrate
Subphylum Cephalochordata (Lancelets) – invertebrate
Subphylum Vertebrata
8
Q
describe Subphylum Urochordata (tunicates)
A
Adults are sessile (don’t move) sac-like filter feeders. their larval form has tail, the adults doesn’t
9
Q
A
10
Q
what is this
A
B. Subphylum Cephalochordata (lancelets)
11
Q
label the lancelet
A
12
Q
A
13
Q
ectothermic vs endothermic
A
ectothermic, meaning that body temperature is dictated by the temperature of the
surrounding environment. Endothermic animals use their metabolism to regulate their
body temperature independent of the environmental temperature.
14
Q
oviparous vs viviparous vs ovoviviparous
A
15
Q
if an animal is oviparous does it have an amniotic egg?
A
yess. Egg in which animals develops inside amnion
16
Q
does having an amniotic egg change what kind of environment animals can be born in?
A
yes, this allows them to live in areas that don’t have as much water. The egg prevents dehydration, provides offspring with nutrients and prevents shock
17
Q
describe the hagfish
A
has slime defence that can suffocate other animals
18
Q
The small holes on the sides of the hagfish, approximately one third down the body, are
openings to the gills. What feature of the ancestral chordate develop into the gills?
A
pharyngeal slits
19
Q
describe the lamprey
A
has a cartilage skeleton and lacks teeth., sucks blood of fish
20
Q
A
21
Q
A
22
Q
The notochord is still present in both hagfish and lamprey. The lamprey also has a
cartilaginous tube with lateral extensions (not visible on this slide) that extend dorsally and
partially enclose the nerve cord. These extensions are the precursors of what anatomical
feature?
A
vertebral column
23
Q
how does a lamprey feed
A
This fish attaches itself to the exterior of another aquatic
animal, rasps through the skin, and feeds on that animal’s blood.
24
Q
what class are sharks and rays
A
(Class Chondrichthyes)
25
describe class Chondrichthyes
These fish have well-developed skeletons made of cartilage, not bone. They are placed in
Class Chondrichthyes, which literally means the cartilaginous fishes
26
What is this structure? label it
27
On the side of the shark’s head and on the underside of the ray’s body are several long slits.
What do these openings enclose?
The long slits on the sides of a shark's head and the underside of a ray's body are **gill slits**, which enclose the **gills**. These structures are vital for the animal's respiratory system.
Sharks and rays are cartilaginous fish (class **Chondrichthyes**) that extract oxygen from water as it flows over their gills. Here’s how it works:
- **Sharks**: Water enters through the mouth or spiracles (small openings near the eyes in some species), passes over the gills, and exits through the gill slits. The gills are rich in blood vessels, allowing oxygen absorption and carbon dioxide release.
- **Rays**: Rays often rely more heavily on **spiracles** (especially bottom-dwelling species), drawing water in through them, as their mouths are often pressed against the seafloor. The water then flows over the gills and exits through the slits on the body’s underside.
This adaptation is key to their survival in aquatic environments.
28
Look at the skate egg case (also known as a “mermaid’s purse”) and the dogfish embryos
on display. Note the yolk sac, still attached to the young dogfish. What is the term for each of
these types of gestation?
skate egg is oviparous and dogfish is ovovoviviparous
29
what class are ray finned-fished. Describe it
(Class Actinopterygii)
Ray-finned fishes are part of a clade of fish called Osteichthyes, which means “bony fish”.
This means that their skeletons are made of bone instead of cartilage like the hagfish,
lampreys and chondrichthyans
30
31
operculum
1. **Protection**: The operculum shields the delicate gills from physical damage, predators, and debris in the water.
2. **Respiratory Facilitation**: It plays a critical role in the fish's breathing process by helping to pump water over the gills:
- The fish opens its mouth to draw in water.
- When the mouth closes, the operculum opens slightly, creating a pressure gradient that forces water to flow over the gills.
- This ensures a continuous flow of oxygenated water, allowing gas exchange to occur efficiently.
3. **Streamlining**: The operculum helps maintain the fish's hydrodynamic shape, reducing drag as it swims.
Unlike cartilaginous fish (sharks and rays), which lack an operculum and rely on multiple gill slits, bony fish have this single covering to house all their gills.
32
33
what are the function of fish scales
34
what is the function of the lateral line system
allows fish to determin direction and rate of water movement
35
function of fins
swimming, balance, stabilit and steering
36
which fin is used for forward
Caudal fin
37
how do sharks move water past their gills
Sharks move water past their gills by either:
1. **Ram ventilation**: Swimming with their mouths open, forcing water over their gills.
2. **Buccal pumping**: Actively pumping water by using mouth and cheek muscles (used by some species).
These methods ensure oxygenated water flows over their gills for respiration.
38
are fish don't homodont or heterodont
homodont
39
wht strutures perform the same function as gills in mammals
lungs (they're analogous)
40
function of gill rakers
aid in gathering of food and protection of gills
41
function of liver in fish
storage of reserve materials and detoxification
42
function of swim bladder
maintain buoyancy at desired depth
43
function of pyloric cecae
add additional areas for nutrient absorption in fish
44
gonads of fish
45
Locate the large fish that has barbels (whisker-like projections on or near the bottom of the
mouth). What is one function of barbels
1. **Locate Food**: Detect prey in murky water or dark environments where visibility is poor.
2. **Sense the Environment**: Feel and taste the substrate (like mud or sand) to find edible material.
Barbels are especially useful for bottom-dwelling and nocturnal fish, such as catfish and goatfish.
46
in what type of habitat would you expect to find fish with barbels
in muddy waters
47
cryptic colouration (camouflage)
defense / tactic that organisms use to disguise their appearance, usually blend in with surrounding
48
what is the defense mechanisms where they look like another organism
mimicry
49
what is countershading
where one part of the body is light and the other is dark, top of sharks blend with the ocean floor when looking down at them, bellies blend with light when looking up at them
50
what is disruptive colouration?
idenity/ location of animal is concealed through visual disruption. makes animal question what it is`
51
what class are lobe-finned fishes.
Class Sarcopterygii
52
describe lobe-finned fished
The Coelacanths were thought to have become extinct over 65 million years ago until live
specimens were discovered in deep water off the coast of Madagascar, East Africa, and in
parts of Asia. These fish have small bony structures in their fins that show the beginning
stages of the tetrapod limb.
Lungfishes are thought to be the aquatic ancestor of terrestrial tetrapods, and are found in
South America, Africa and Australia. Look for the four slender fins on the body of the lungfish
in the picture
53
Do you notice anything different about the fins in this group compared to the Ray-Finned
Fishes?
have lobe fins instead of ray fin
54
what class are amphibians a part of? describe it
Class Amphibia.
examples include axolotyl, frogs, salamander, newt
Amphibian skin is very thin, usually moist, and covered with a thin layer of mucus. Many
amphibians rely on gas exchange through their skin to supplement breathing with their
lungs. Some species do not even have lungs and rely solely on respiration through their
skin.
55
where do amphibians spend their life
Most amphibians spend part of their life cycle in an aquatic environment and part of their life
cycle in a terrestrial environment (some are entirely aquatic.) Most amphibians lay their
unshelled, non-amniotic eggs in masses, either in water or in a moist environment near
water. The male will fertilize the eggs as the female deposits them.
56
what are tadpoles
Once the eggs hatch, the
young frogs are called tadpoles.
57
what class are reptiles
describe them.
class Reptillia (FIRST TO SHOW AMNIOTIC EGG)
Reptiles have an amniotic egg with a leathery outer layer. This egg provides the embryo
with a very secure and drought-resistant environment to develop in. This evolutionary
development allows many reptiles to be exclusively terrestrial, and even aquatic reptiles
(crocodiles and sea turtles) lay their eggs on land.
58
Is fertilization internal or external in reptiles? How do you know?
is it the same for amphibians?
internal because they lay eggs
no, external for amphibians
59
term for animals that lays eggs
oviparous
60
what is ecdysis
Snakeskin is composed of overlapping scales that cover the entire body and are derived
from the epidermis of the skin, unlike the scales of fish. Snakes shed their skin on a regular
basis, usually once a month; this process is called ecdysis
61
why do snakes shed their skin
doesn't fit anymore, worn out
62
How do snakes, lizards, crocodiles, and turtles raise their body temperature if they are too
cold?
bask in the sun
63
what subclass are birds? Describe them?
Subclass Aves
The relationship of birds to other animals has long been debated, but the overwhelming
evidence suggests that they are descended from one group of dinosaurs and are a subclass
of Class Reptilia. Crocodiles are actually more closely related to birds than they are to any other reptiles.
The Archaeopteryx is a fossil specimen that has the skeletal features of a small dinosaur, including a long bony tail and a mouth with teeth, but there are also feathered wings clearly imprinted in the rock.
ENCOTHERMIC
64
what common characteristics of these skulls are representative of these birds
beaks
65
what feauture typically found on jaws is absent in birds
teeth
66
are reptiles endotherms or ectotherms
ectotherms
67
what are the one of the distinguishing feature of Subclass Aves
The distinguishing feature of Subclass Aves is the presence of feathers. These keep the bird
warm as well as provide the airfoil shape to their forelimbs that allows birds to fly. Different
feathers are adapted for different functions.
68
what class are mammals.
Class Mammalia
69
What two characteristics distinguish Class Mammalia from other vertebrate classes?
1. **Mammary Glands**: Mammals produce milk to nourish their young through specialized glands.
2. **Hair or Fur**: Mammals have hair or fur at some stage in their life, which provides insulation and aids in temperature regulation.
These features are unique to mammals and set them apart from other vertebrates.
and feathers
70
homodont vs heterodont
Unlike reptile and amphibian teeth, which are homodont (all teeth have the same general
shape and function), most mammals have heterodont dentition
71
incisors
Front teeth that are used for cutting or gnawing food into manageable pieces.
72
canines
Next to incisors. They are used for tearing and piercing food, holding prey and
for behavioral displays. They are more prominent in the cat, pig and hippopotamus than
in humans. In some herbivores, the canines have been lost (ex. beavers) or they may be
modified to act similarly to incisors (ex. horses).
73
Premolars and Molars:
Next to the canines, at the back of the mouth. These teeth vary
tremendously in shape depending on the type of food the animal eats
74
carnivores, the molars are shaped like
mountain peaks; they are slender and pointed
at the top. When the animal closes its teeth, the molar on the top jaw slides down beside
the molar on the bottom jaw, and the food is shredded in an action similar to a pair of
scissors
75
herbivores, the molars are
wide with raised ridges across the entire tooth; in addition,
the upper molars close down on top of the lower molars. These molars are specialized
for the sideways grinding motion of the jaws which is necessary for grinding tough
fibrous plant material. Another feature typically seen in herbivores is a gap between the
incisors and the molars.
76
In omnivores, the molars are
wide and have rounded or bumpy surfaces. Most
importantly, the top molars close on top of the lower molars instead of beside them to
crush food.
77
Would an animal with wide ridged molars and canines that resemble incisors be an
omnivore, carnivore, or herbivore?
herbivore
78
There are three groups of mammals with very distinctive reproductive characteristics:
Monotremes, Marsupials and Eutherians.
Monotreme mammals lay eggs, marsupials
have a pouch in which their young finish their embryonic development. Eutherians (placental
mammals) nourish their developing embryos in the uterus with a placenta.
79
out of all the groups (Monotremes, Marsupials and Eutherians) which one is viviparous
which are oviparous
eutharians
monotremes
80
