1. Evidence of Evolution

2. I. Biological Evolution:
• A change in a population from one generation
to the next

3. BUT ITS NOT THAT SIMPLE – all things can change
but if they do not involve descent through
genetic inheritance, it cannot be described as an
example of biological evolution

4. Changes are due to GENE FREQUENCY in
populations

5. Changes involve DESCENT of a different species
from a COMMON ANCESTOR over generations

6. Leaves on trees change color
and fall over several weeks.

7. Mountain ranges
erode over millions of
years.

8. A genealogy illustrates
change with inheritance
over a small number of
years.

9. Over a large number of
years, evolution produces
tremendous diversity in forms of
life.

10. II. Evidence of Evolution
a. Fossil Records: RELICS or IMPRESSIONS of
organism from the past preserved in ROCK
showing the succession of organisms

11. • Each layer is a boundary of CATACLYSMIC
CHANGES that destroyed many species at that
time in an area
Floods
Eruptions
Meteor Impacts

12. • The DIVERSITY of species increased the chance
of some species surviving these events due to
adaptation over time

13. b. Homology: different organisms share similar
characteristics from a COMMON ANCESTOR

14. • Structures may look similar, BUT HAVE A
DIFFERENT FUNCTION
• Altered version of ancestors

15. • Ex: All MAMMALS have same number of
bones in forelimb, but the
position, shape, and function are different
What are the
functions of each of
these limbs?
We call these
homologous
structures…similar
structure, different
function

16. c. Analogy: different organisms share similar
characteristics despite DIFFERENT ANCESTORS

17. • Structures look similar, AND HAVE THE SAME
FUNCTION
• Changes due to response to
ENVIRONMENT, nature shaped ADAPTATIONS

18. • Ex. Winged animals: insects, birds, and bats

19. d. Embryonic Development:
• Adult homology MAY NOT be apparent
• During mitotic divisions, stages of offspring
DEVELOPMENT of different species may have
similar appearances (morphologies)
• Similar structures may develop different functions

21. Ex. All vertebrates have PHARYNGEAL POUCHES
– which develop into gills in fish, or tubes in ears
that connect to throat in humans

22. e. Biochemistry:
similar species share
nearly the same
genetic machinery
• Similar DNA and
RNA sequences
• Similar AMINO
ACID sequencing
• Ex. Hemoglobin
and digestive
enzymes

23. Learning Check
Answer the following questions based on the
information covered in your notes.
Example:
1. Humans, chimpanzees, whales, and bats all have the same bones
in their arms, fins, or wings.
a. What type of evidence is this? homologous structures
b. Why is this evidence of evolution?
This is evidence of evolution because if all these animals have
the same bones, they probably all evolved from one creature
that had those bones a very long time ago. Some of its
children evolved (or changed) into humans, and other evolved
into whales or bats or chimpanzees.

24. 2. Scientists find fossilized bones of a huge
animal that doesn’t exist today.
a. What type of evidence is this?
b. Why is this evidence of evolution?

25. 3. The human gene for your muscle protein is
different from monkey muscle protein in 4
places and different from a chicken’s gene in 25
places.
a. What type of evidence is this?
b. Why is this evidence of evolution?

26. 4. Honey possums lick nectar from flowers using
a long tongue made of soft muscle. Butterflies
lick nectar from flowers using a long tongue
made of hard protein.
a. What type of evidence is this?
b. Why is this evidence of evolution?

27. 5. Humans, rabbits, and zebras all have an
appendix, an extra piece in their digestive
system, although in humans it’s much smaller.
a. What type of evidence is this?
b. Why is this evidence of evolution?

28. Let’s get this straight…
• Misconceptions about humans…The
phylogeny of living species most closely
related to us looks like this
It is important to remember that:
• Humans did not evolve from chimpanzees.
Humans and chimpanzees are evolutionary
cousins and share a recent common ancestor
that was neither chimpanzee nor human.
• Humans are not "higher" or "more evolved"
than other living lineages. Since our lineages
split, humans and chimpanzees have each
evolved traits unique to their own lineages.
From http://evolution.berkeley.edu