Most familiar organisms:

1
Most familiar organisms

• Mammals

2
MAMMALS

• Mammals (or Class Mammalia)
• are an ancient group of vertebrates.

3
Geological time scale

• Cenozoic
• 65 MYA to present
• Mesozoic
• 245 MYA to 65 MYA
• Paleozoic
• 540 MYA to 245 MYA
• Proterozoic or Precambrian not shown

4
MAMMALS

• Origin in latest Paleozoic--early Mesozoic
• from "mammal-like" reptiles
• Mesozoic mammals (fossils) small
• shrew to housecat size

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MAMMALS

• Mass extinction at end of Mesozoic
• Cretaceous-Tertiary K-T boundary
• large dinosaurs all died,
• most old mammal groups died too.

6
MAMMALS

• Mammals evolved radiated to diverse group
  during early Cenozoic (Tertiary).

7
Distinguishing characters

• Distinguishing character
• trait or characteristic found throughout a group
  and not in any other group.

8
Distinguishing characters of Mammals

• http//facstaff.gpc.edu/apennima/Diversity/mammal
  s.htm

9
Mammal sub-classes

• Sub-class Monotremes
• egg-laying mammals,
• 3 living spp. in one order
• Sub-class Marsupials
• pouched mammals,
• about 240 living spp.
• Sub-class Placentals
• embryo/fetus attached to placenta in uterus

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Sub-class Monotremes

• Ancient group w/ few survivors
• echidnas
• platypus
• Intelligent, highly specialized
• Retain cloaca ("one hole") for urination,
  defecation, reproduction

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Sub-class Monotremes

• Retain cloaca ("one hole") for urination,
  defecation, reproduction

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Sub-class Marsupials

• Pouched mammals,
• about 240 living spp.
• Embryo attaches to uterus, temporarily
• born immature, still embryonic
• "embryo" creeps from vagina to marsupium (pouch),
  attaches to nipple, grows in pouch
• Origin in S. America (?) in late Mesozoic (?)
  early fossils from N. America.

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Sub-class Marsupials

• S. America
• 6 families in late Cenozoic, 2-3 MYA
• 2 families still living (opposums)
• Australia
• 10 living families
• evolved to most ecological roles
• herbivores kangaroos, wombats, koalas
• carnivores marsupial "cat," Tasmanian "wolf,"
  T. devil
• insectivorous small dasyurids, bandicoots,
  numbat (anteater-like), etc.

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Sub-class Placentals

• Most (about 4000 species) living mammals
• Embryo attaches to uterus, forms placenta
• exchange nutrients, wastes with mothers
  bloodstream
• born more mature (variable)
• Orders
• http//facstaff.gpc.edu/apennima/Diversity/mammal
  s.htm

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Domestication of mammals

• Uses ?
• Domestic species ?
• Why these species ( not others) ?