Download 31.3 Vertebrates (cont*d) - Westgate Mennonite Collegiate

31.3 Vertebrates
(cont’d)
Amphibians, Reptiles, and Mammals
Amphibians
O
O
O
O
About 6,600 species
Live on both land and water ( = amphi)
Include frogs, toads, newts, salamanders
Differences from fishes:
jointed appendages
four limbs
eyelids (keep eyes moist)
voice-producing larynx
lungs (although many adults breathe through
their skin)
O 3-chambered heart
O
O
O
O
O
Reptiles
O About 15,000 species
O Include many extict species, including
dinosaurs
O Include snakes, lizards, alligators, turtles
and birds
Reptiles (continued)
O Adaptations to land life:
O Hard scales
O Tongue as sense organ
O 3 or 4-chambered heart (incomplete septum in
ventricles in some species)
O Sexual reproduction is direct (sperm directly
deposited into female and fertilization takes place
internally in the female)
O Amniotic egg produced is typically leathery,
flexible and shelled
O Most are ectothermic (cold-blooded)
Birds (continued)
O Birds are actually feathered reptiles
O Differences b/t birds and other reptiles:
O Endothermic (warm-blooded)
O Hard-shelled eggs
O Feathers
O Septum in ventricle complete (4-chambered
heart)
Mammals
O Evolved from reptiles
O About 4,600 species
O Mammalian groups include:
1.
Monotremes
a)
b)
c)
Lay hard-shelled eggs
Include spiny anteater and duckbill
platypus (both found in Australia)
After hatching, remain in burrow where
they are nursed for up to 2 months
Mammals (continued)
2.
Marsupials
a)
b)
c)
d)
e)
f)
Begin development inside female’s body
Born immature and finish developing in a
pounch in mother’s abdomen
Attach there to nipples of mammary gland
and continue development
Mainly found in Australia
Underwent adaptive radiation there w/o
competition with placental mammals
Include koalas, kangaroos, Tasmanian
devil,
Mammals (continued)
3.
Placental mammals
a)
b)
c)
d)
e)
f)
Vast majority of mammals
Extraembryonic membrane adapted for internal
development within the uterus
Attachment to placenta through umbilical cord
(allows for nutrient, gas and waste exchange
b/t mother and fetus’ blood)
Extremely well-adapted to life on land (hair,
large lungs)
Very developed brain
Differentiated teeth