Transcript Natural Selection and Evolution of mammals

Natural Selection and Evolution of
mammals
http://www.youtube.com/watch?v=FNz9aHUTAT8
6:40
Evolution are the changes in the gene pool of a
population over time.
Natural selection process by which individuals that are
better suited to their environment survive and
reproduce most successfully.
Adaptation is an inherited characteristic that increases
an organism’s chance of survival.
13:13
http://www.youtube.c
om/watch?NR=1&v=s
vHQ4BQY__o&feature
=endscreen
Darwin
Wolf
Pinta
Marchena
Genovesa
Santiago
Bartolomé
Fernandia
Råbida
Pin zon
Seymour
Baltra
Santa Cruz
EQUATOR
Santa Fe
Tortuga
Isabela
San Cristobal
Española
Floreana
Galåpagos
Islands
Marine Iguana
Land Iguana
KONA
FINCH
extinct
KAUAI AKIALAOA
AMAKIHI
LAYSAN
FINCH
IIWI
AKIAPOLAAU
APAPANE
MAUI
PARROTBILL
fruit and seed eaters
insect and nectar eaters
FOUNDER SPECIES
Based on his
observations,
Darwin proposed
that EVOLUTION
occurs by
NATURAL
SELECTION.
Darwin’s Postulates
• 1. Individuals within populations vary.
• 2. Some of these variations are passed on to offspring.
• 3. In every generation some individuals are more
successful in surviving or reproducing than others.
• 4. Survival and reproduction are not random.
Individuals with the most favorable variations are
more likely to survive and reproduce.
MONOTREMES
Platypus
Spiny anteater
MARSUPIALS
Koala
Tasmanian Devil
PLACENTAL MAMMALS
Bat
Arctic Fox
Walruses
Manatee
RACCOON RED PANDA
DIVERGENCE
approximately
40 million years ago
GIANT PANDA
SPECTACLED
BEAR
SLOTH SUN
BEAR BEAR
BLACK
BEAR
POLAR
BEAR
BROWN
BEAR
DIVERGENCE
15-20 million years ago
Fig. 20.10, p. 319