1. 7. Class - Mammalia ~4500 species in 19 orders
Characteristics
hairy animals with glands that produce milk
maintain constant body temp.
most develop in the uterus where they are nourished by a placenta
limbs are under the body, directed downwards
fully mobile jaw and socket teeth

2. Origins
probably arose from therapsids (200mya) which are mammal-like reptiles

3. survival was probably enhanced by carrying embryos within the body, bearing live young, and the constant food supply (milk)
by the end of the Mesozoic era (65 mya) mammals diverged from the original line to three “groups” (probably sub-classes) -- Monotremes, Marsupials, and Placentals

4. 1. Monotremes Subclass: Protothereia, Order: Monotremata
egg (leathery)-laying mammals
have a sense of electroreception to locate their prey
only five species exist, the duck-billed platypus and four sp. of spiny anteaters (Echidna)
single hole that serves the urinary tract, anus, and reproductive tract
Ornithorhynchidae
(Ornithorhynchus anatinus)

5. 2. Marsupials Subclass – Theria or Metatheria Supercohort-Marsupialia
the pouched animals- 272 species.
short gestation time is due to having a yolk-type placenta in the mother marsupial
young are typically born in a practically embryonic state (2cm).
Ex. Opossum, koala, wallaby, wombat, kangaroo, and Tasmanian Devil....

6. 3. Placentals (subclass Eutheria)
nourished in the uterus through a specialized embryonic organ attached to the uterus wall called the placenta allowing longer gestation times.
4000+ species. whales, bats, elephants, armadillos, dogs, sheep, cattle, and humans....

7. Order – Primates Characteristics and origins
233 living species placed in 13 families
most have long arms, prehensile (grasping) tail and hands with fingernails
stereoscopic vision with eyes in front of head
brain adapted for learning
probably arose about 65 mya
early primates were more like rodents that lived in trees

8. Human classification/taxa
Kingdom:   Animalia      Phylum:   Chordata           Subphylum:   Vertebrata                Class:   Mammalia                     Subclass:   Theria                          Infraclass:   Eutheria                               Order:   Primates                                    Suborder:  Anthropoidea                                         Superfamily:   Hominoide                                             Family:   Hominidae                                                   Genus:   Homo                                                        Species:   sapien
Animalia
Chordata
Mammalia
Primate
Hominidae
Homo
sapiens sapiens
Did Humans Evolve video clip