Download Vertebrate Animals

Vertebrate Animals
Phylum: Chordata
• 4 basic characteristics distinguish chordates
from other animals
1) presence of a notochord
a) a flexible, rod-like structure which
runs the length of the back side
b) replaced by backbone in chordate
adults
2) presence of dorsal nerve cord
a) hollow tube above notochord
b) becomes brain and spinal cord
3) presence of gill slits (at some point in
development )
a) openings in the wall of the
pharynx
passage of water/oxygen
4) Presence of post-anal tail
a)an muscular extension of the body
that runs past the anal opening
b) In some species, like humans, this
feature is only present during the
embryonic stage.
• All chordate embryos have these
characteristics. Most will however lose or
modify one or more of these structures as
they mature into adults.
• 5 major classes of Chordates
1) fish
2) amphibians
3) reptiles
4) birds
5) mammals
Fish
A) Agnatha: jawless fish
1) suction mouth to attach to prey, slit it open and
feed on blood and tissues.
2) notochord remains
a)lack bony skeleton  internal skeleton is
made of cartilage
3) gills for gas exchange, not so much for feeding
EXAMPLES: lamprey and hagfish(modern jawless
fish that are parasitic)
*
B) Chondrichthyes: cartilage fish
1) moveable jaw (can grasp, chew and
crush).
2) skeleton made of cartilage rather then
bone
3) scales (spiny and sandpaper like)
4) ex. sharks and rays
C) Osteichthyes : bony fish
1) skeleton made of bone (begin by
forming a skeleton of cartilage)
2) presence of a swim bladder (allows gas
to enter and leave the blood. Gas bag which
control’s the fish’s depth. By changing volume
in bag, they can control how deep they are.)
EXAMPLES: tuna, trout, salmon, goldfish
General characteristics of fish
1) ectotherms (they can’t regulate body
temperature)
2) gills used for respiration
3) body covered in scales
4) fins aid in movement
5) digestion, respiration, circulatory,
excretory, nervous and reproductive systems
Amphibians
A) evolution of the tetrapod
1) fins develop into limbs (need to be
more muscular then fins to allow them to move
on land, often have joints like elbows )
*
https://www.youtube.com/watch?v=xkVgpYoiF
mw
B) 3 classes
1) frogs
2) toads
3) salamanders
C) live a portion of life cycle in water
1) reproduction (external fertilisation)
2) metamorphosis
Amphibians means “dual-life”. Hatch from
eggs as fishlike larvae and at some point
undergo metamorphosis, changing into and
adult which can survive on land.
D) life on land
• Start out in water, has fins for moving and gills for gas
exchange in water.
• After metamorphosis:
1) lungs for gas exchange with air
2) legs for movement on land
3) moist, smooth skin for gas exchange
a) risk of drying out
b) gravely affected by pollution
4) ectothermic: live in areas where
temperature does not vary too much, other wise
they have special adaptations to help them
survive.
Reptiles
A) 4 major groups
1) lizards
2) snakes
3) turtles
4) crocodilians
B) fully adapted to life on land
1) scales (prevent dehydration)
2) lungs for gas exchange
3) limbs point downward, with claws. Its
body is higher off the ground which makes
fast movement over land easier
4) ectothermic (basking in the sun to heat
up and get energy
5) internal fertilisation (sperm fertilized
eggs inside)
6) development of egg with a shell
a) amniotic egg
Birds
1) 2 legs + 2 wings
a) scales & claws on leg
(usually four toes, webbed feet
for swimming fish like ducks)
2) body covered in feathers
a) made of keratin (like scales of
reptiles)
b) keratin forms a hollow tube (shaft) =
light
weight
c) several functions
•
warmth (down feathers, closest to body)
•
coloration(identifies one bird from another
and establishes territory and mates)
•
flight*** (Quill featgers on wings and
tail which help the bird to lift. Several
adaptations)
•
contour feathers to give them their shape.
d) molting (loss of feathers which are
replaced by new ones.
3) skeleton made of hollow bones p. 575-576
4) toothless beak
a) several different shapes, nostrils
(nares)
b) Used for scratching, cleaning, repairing
feathers, collecting materials,
protection against other predators and
to eat.
c) Size and shape adapted to diet.
5) eyes on either side of head (never look at the
same spot with both eyes
a) some birds an exception (ex. owls)
6) more vertebrae on neck than other
vertebrates
a) it can turn head 180°
7) endothermic
a) can regulate body temperature
i) 45°C
8) internal fertilisation
a) amniotic egg (bird lays egg about 2 days
after fertilization.)
b) mother/father cares for young
9) 4 chambered heart (important feature for
animals which require a lot of oxygen)
Mammals
A)characteristics
1)highly developed brain
a) large cerebrum (allows mammals to perform
complex tasks)
b) convolutions ( capacity of the brain is
increased because it is folded upon itself in
ridges and grooves)
2) endothermic: regulate heat and
temperature with sweat glands
3) breathe with lungs, aided by using
diaphragm muscle
4) hair: regulate heat
a) blubber/fat beneath the skin in
aquatic mammals
i) lost hair as a streamlining
adaptation
5) 4 types of glands
a) sweat glands (regulate body temp.)
b) sebaceous glands (lubricate hair, skin)
c) scent glands (communication)
d) mammary glands (nourish young)
6) highly developed teeth
a) diverse diets (herbivores, carnivores,
omnivores)
7) internal fertilisation
a) young develops in uterus
i) mother/father cares for young
*the more complex the mammal, the longer
it associates with mother after birth.
8) 4 chambered heart
B) 3 mammal groups
1) monotremes (ex. duck-billed platypus,
echidna)
a) lay eggs
b) milk from sweat glands
2) marsupials
a) original development in uterus
b) young are born very early in
development and further development occurs
in pouch
c) milk from mammary glands
*
3) placental mammals
a) long gestation period
i) remain in uterus until highly
developed (time depends on size and
type of mammal)
ii) placenta nourishes young through
umbilical cord
b) young nourished with milk