Download EVOLUTION

WHAT EVIDENCE DO
WE HAVE TO
SUPPORT THE IDEA
OF EVOLUTION BY
NATURAL
SELECTION?
FOSSILS


any remains of life from
an earlier time and the
most abundant evidence
for evolution
Sedimentary rock
contains the most fossils
and is formed from mud,
sand, and other fine
particles
How do scientists figure out how old something is?

Relative Dating —
looking at where
the rock is
located. Older
layers are deeper
than the layers
above. This
method only
provides an
estimated age of a
fossil.
How do scientists figure out how old something is?

Radioactive Dating —measuring how a
radioactive element in the fossil (like Carbon
or Uranium) has decayed. They compare the
amount of stable rock to amount of
radioactive element still present.
Not the same kind of dating… 
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html

Fossils document how organisms
changed over time, but much of the
fossil record is missing or incomplete
(like a book with pages ripped out)!
Fossil Hunting on the Galapagos
THERE ARE DIFFERENT KINDS
OF FOSSILS…AND DIFFERENT
WAYS THAT FOSSILS CAN
FORM…
Amber Fossils
Fossils that are hardened in
tree sap…
Prehistoric termites trapped in amber
Lizard in Amber
Frog in Amber
Bones…
Frozen in ice or
permafrost…
Woolly Mammoths
When do humans
“show up” on the
planet?
Additional Video Clips
Geologic Time by Brainpop
Fossils by Brainpop
Fossils Adv. by Brainpop
HOMOLOGOUS STRUCTURES
body parts that are similar in origin
and structure.
Example: arms, dolphin fin, bat wing,
bird wing

VESTIGIAL STRUCTURES

A body part that is reduced in size
and does not seem to have a function.
Examples: human appendix, wisdom
teeth and muscles that are for
moving the ears.
EMBRYOLOGY

study of the development of
embryos (an organism in its earliest
stages of development).
Examples: gills
and tailbones
in humans
What similarities do you see between these embryos?
COMPARING DNA CODES

the closer the DNA sequences are in
organisms, the more closely related
they are.
Example: DNA has shown that dogs are
the closest relatives of bears.
Human’s closest relatives are from
the ape family.
Cousins?

Example: Humans are most closely
related (99.9%) to chimpanzees.
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html
Other Video Clips
Woolly Mammoths
Elephant Evolution
WHAT CONCLUSIONS
CAN BE DRAWN FROM
THESE CONCEPTS?
DIVERSITY

over millions of years, the process of
natural selection has created all the
different life forms on Earth.
Scientists estimate anywhere from 5
million to 100 million species on the
planet, but have only identified about
2 million.
DIVERSITY
CLICK HERE FOR A
BIODIVERSITY
INTERACTIVE MAP:
http://www.biodiversityho
tspots.org/xp/Hotspots/p
ages/map.aspx
RELATEDNESS

since species evolve from one to the
other, there is always a degree of
similarity between them. Generally, the
more closely related they are, the more
recently they evolved or separated into
distinct species. All species are connected
on earth because they all share some level
of DNA.
RELATEDNESS
RELATEDNESS
TREE OF LIFE WEB PROJECT:
http://tolweb.org/tree/
EXTINCTION


occurs when an entire species dies out
Due to a change in the environment
without time to adapt/evolve to survive
in it
EXTINCTION BY BRAINPOP