Download Aim: What the evidence that supports Evolution?

Aim
Evolution: What evidence do
scientists have?
How do we know that we have evolved
from ancestors that are different from us?
FOSSILS
Hint: How do we
know dinosaurs
existed?
http://www.amnh.org/exhibitions/permanent-exhibitions/foss
halls/paul-and-irma-milstein-hall-of-advanced-mammals
What is a fossil?
Remains or traces
of organisms that
lived in the past
Ida- 47 MILLION years old
3D Model_
http://news.bbc.co.uk/2/hi/science/natur
e/8057465.stm
Lucy!
"Lucy" is one of the most complete skeletons found to
date from the early hominids that flourished between 4
and 2 million years ago. The skeleton consists of bones
from a single individual, presumably female, who stood
well under 4 feet tall.Discovered by scientists in 1974,
the 3.18-million-year-old Lucy was named after the
Beatles song "Lucy in the Sky with Diamonds," which the
researchers listened to as they celebrated their
remarkable find.
What do we learn from fossils?
We compare current species to fossils to
get clues about:
• What species may it have evolved from?
• What species is it similar to?
• How long did individuals live in the past?
• How do organisms change over time?
• Why do organisms change in appearance?
http://www.ucmp.berkeley.edu/education/explorations/tours/stories/middle/C7a.h
tml
The fossil record shows…
• Life has evolved from simple to more
complex over time
Did all ancestral species evolve into
modern species?
• No, some became extinct because they
were not able to adapt to the changing
environment
Evolution- fossils
https://www.youtube.com/watch?v=ewtw_nZUIDQ
7:00
Other types of Evidence for Evolution
COMMON ANCESTOR
Comparative Studies
Study of similarities between living things.
Why do scientists use comparative
studies?
• To observe how closely related organisms are to each other
•
To see patterns in how species have changed over time
If species are similar – It provides evidence that they are
related
• Who are we closely related to?
– Chimpanzees!
• Who are we distantly related to?
– Orangutan
Comparative Anatomy
What is anatomy?
– Study of how
organisms look on the
inside (structure).
Comparative
anatomy:
Study of structural
similarities and
differences in living
things
• How are they similar?
• How are they different?
Which two organisms are the most
closely related?
VESTIGIAL ORGANS
The appendix and the tail
bone are both VESTIGIAL
organs.
Vestigial structures- have
no function.
Why would an organism have
organs with little or no
function?
They were useful to the
ancestor it evolved from.
Hind leg in whales
Which is Which?
Which is the
gorilla, fish and rabbit?
Comparative Embryology
• Compares the embryos of organisms
• The babies develop in a similar way- shows
they are related
Comparative Biochemistry
• Compares the DNA or Amino Acids (Proteins) of
organisms in order to find relationships
The more DNA they have in common, the closer related
they are
Who is the most closely related to
humans?
Common Ancestor
• This evidence of similarities between organisms
leads to the idea of:
COMMON ANCESTRY
• All species living and extinct came from a
common ancestor – they are all related – some
more than others!
Evolution videos
• http://www.pbs.org/wgbh/evolution/
educators/teachstuds/svideos.html
•
https://www.youtube.com/watch?v=p3D3KX0l7M8
The Human Family Tree