Transcript Mesozoic, Cenozoic and Evolution

The Mesozoic Era- Mammals Develop
 1. Pangaea began breaking apart resulting in
earthquakes, volcanoes, and mountain building.
 2. The Mesozoic has three periods: the Triassic,
Jurassic and Cretaceous.
Triassic
 hot climate, the Atlantic ocean forms
 mammals appear- They have hair or fur, and most
offspring are born live, not from eggs
 trees and ferns are still common
first dinosaurs
appear- They are
small, no bigger
than chickens, have
small heads, long
tails and walk on
their hind legs
Mesozoic: Jurassic
 “ Age of Dinosaurs” – “Jurassic Park”
 Two main groups of dinosaurs based on hip structure
 Ornothischia (bird hipped) had 5 main categories
Stegosaurus, ankylosaurs, ceratopsians,
pachycephalosaurs, & ornithopods
 They were mainly herbivores
Bob Gardner's "Dinosaurs" Planetarium Show, The
Evolutionary Relationships of Dinosaurs

 Sauruschia were the lizard hipped dinosaurs- there were
two types
 Sauropods- quadrupedal (four legs), herbivores
 Brachiosaurus, Brontosaurus, Apatosaurus
 Theropods- bipedal (two legs), carnivores
 Tyrannosaurus Rex
 Velociraptor
Sauropods
Mesozoic: Jurassic Cont…
 First bird appearedArchaeopteryx
 Means “ancient wing”
 Bird with teeth and
reptile skeletal structure
 Transition fossil
 Between reptiles and
birds
Cretaceous period
 Dinosaurs still flourishing
 sea level has dropped, waters dry up
 first flowering plants
End of the Cretaceous Period and Mesozoic Era
 At the end of the Cretaceous
period and the Mesozoic Era
is the mass extinction of
most life on earth. A
meteorite hit in the
Yucatan Peninsula off the
coast of Mexico.
 This caused enormous explosions, tsunamis,
wildfires, and so on. Over time, the dust from the
collision that rose into the atmosphere blocks out
the sunlight plunging the earth into colder
temperatures. This results in starvation of many
species or the inability to adapt to a new climate
and their extinction. Today we see a layer of
Iridium around the world to support this.
Cenozoic “Age of New Life”
 A world with people
 Began 65 million years ago,
after the meteorite impact
 Divided into 2 periods ->
Tertiary –for evolution of 1st
horses. Quaternary- for
evolution of 1st animals to
walk on 2 feet. Near end of
Tertiary, humanlike creatures
began to walk upright on
African plains-“Lucy” found
in 1977 (3.4 myo)
 3.Primates are mammals with opposable thumbs and
two eyes in the front of the skull. They have nails vs.
claws, they care for infants and they have higher
intelligence.
 4. Homonoids include three groupings- the great apes,
the lesser apes and the Hominids.
 Homonids are bipedal. The hipbone supports the
upright walking, also have larger brains, smaller faces
and greater dexterity.
Evolution: Change over time
 Evolution is change over time
 A species is a group of organisms that can
SUCCESSFULLY interbreed, produce fertile offspring
 Ex. Lions and tigers are similar and can breed
(producing Ligers or Tigons) BUT offspring are NOT
fertile- Not same species.
 Ex. A horse and a donkey can mate and result in a mule
but it’s not fertile- Not the same species.
 Ex. A beagle and a German shepherd look different but
share similar characteristics. Can breed and produce
fertile offspring –same species.
Liger
Tigon
Horse
+ Donkey = mule
+
=
 A gene is a unit of heredity that is passed from parent to
offspring. Ex. eye color, hair color, length of arms, etc.
 A mutation is a change in gene. Can be good or bad.
 Mutations: Agents of Change
 1. After most mutations the organism can’t survive and
dies, often before birth.
 2. However, sometimes it’s a positive change.
 3. A change that increases organisms’ chances of survival
is an adaptation.
 4. Better adapted =more offspring =so many adaptations
may take place that a new species evolves! May result in
extinction of previous species.
Evolution Example
Bacteria
Jellyfish
Fish
Worms
Amphibians
Reptiles
Dinosaurs
Birds
Lizards
Mammals
Primates
Felines
Humans
Lions
 TeacherTube Videos - Simpsons Evolution