This document provides an overview of prehistory and how life has changed and evolved over time. It defines key terms like adaptation, species, population, and evolution. It describes how fossils are formed and how scientists use fossils and dating techniques to reconstruct evolutionary histories and sequence fossils. Examples of homologous and analogous structures in different species are given. Charles Darwin's theory of natural selection and evidence for it, like peppered moths and pesticide-resistant insects, are summarized. The concepts of speciation and examples of geographic separators are also outlined.

1. Prehistory 2:
Life Changes
ppt. by Robin D. Seamon
HOOK VIDEO: COSMOS- World
Set Free

2. DEFINITIONS:
Adaptation- physical characteristic or behavior
that allows an organism to survive and
reproduce in its environment
Species- group of organisms that can mate to
produce fertile offspring
population- groups of same species living in the
same place
evolution- process in which inherited
characteristics within a population change over
generations such that new species sometimes
arise

3. Fossil- remains or imprints of once-living
organisms found in layers of rock
Fossil record- historical timeline based on fossils
found in Earth’s crust
CONNECTING:
* Fossils are hard to form & find (esp. on land)
* There are blank places in our record
* Disturbances in the strata/rock record
1858: 1st almost complete dino skeleton found

4. HOW DO FOSSILS FORM?
Petrified Fossil: fossil completely turns to stone
1. Organism dies in right place: sediments cover (lake
bottom, mud flats)
2. Soft parts decay or are eaten
3. Sediments layer; pressure causes sediments to
fuse together, encasing organism like a shell
4. Ground water with minerals seeps around the
bones; minerals left in bone spaces & may replace
whole bone
5. Rock layer needs uplifted & layers above eroded
for fossil to be DISCOVERED

5. Scientists use logic & carbon dating to
sequence & draw connections among fossil
findings all over the world

6. http://abyss.uoregon.edu/~js/lectures/age_of_the_earth/age_of_the_earth.html

7. What do scientists do?
Geologists & Paleontologists
Compare skeletal structure
Compare DNA
Date the fossils
Put into logical order as new fossils are found

8. http://www.ucmp.berkeley.edu/fo
srec/McKinney.html
Which rocks
are oldest?
Most recent?
Which fossils
would be
oldest?
Most recent?
A: Most recent
rocks-
Those on top &
those cutting
through others

9. Rocks on the top & those intruding are the
youngest.
Rocks on the bottom are older.
Erosion on a layer with other layers piled on top
means the eroded layer is older.
Erosion (unconformity) means an environmental
change: physical weathering-wind, water,
temperature

10. SIMILAR STRUCTURE? = TWO REASONS:
Homologous structures same structure,
different function; evolved from common ancestor
human arm, horse leg, bird wing
Analogous structures performs same function;
evolved from different origins (independently)
WINGS: birds, bats, butterflies
ADVANCE

11. Analogous Structures
http://web1.d25.k12.id.us/home/staff/rudeer/homoanalvestig.html

12. Homologous Structures
BACKhttp://itc.gsw.edu/faculty/bcarter/histg
eol/paleo2/homol1.htm

14. EXAMPLE:
Whale
Evolution
p. 619
http://evolution.berkeley.edu/evosite/e
vo101/images/whaleancestors.gif

15. Vistigial Structures: structures that have
lost their ancestral use in a species but
have been retained
through evolution

16. Similar skeletal features reveal
important evolutionary links
among vertebrates. Structures
such as bones that have a
common
origin but different function are
called homologous structures.
COMPARING SKELETONS LAB
Homologous structure- body part with same origin in different species but
may not serve the same functions now.
DIRECTIONS: Color the homologous bones the same color in each species.
Header: CS 1
Activity 1:
Activity 2: Choose 3 colors. Decide which skeletons appear most similar. Color similar skeletons the same color.

17. COMPARING SKELETONS LAB 2

18. http://www.indiana.edu/~ensiweb/lessons/gr.fs.fd.html
Make a poster to show your final interpretation of the fossils as well as how your
interpretation changed as you got more information.
Each person’s handwriting must be on the poster.
Include in your poster:
• The type of animal you think your fossils were
• A drawing of what the animal might look like
• Where the animal might have lived (in water, on land, on land and in the air) and why
you think so
• What you originally thought the animal was on Day 1
• The biggest piece of evidence that caused you to change your interpretation from Day1
to Day 5
• What new pieces of evidence (such as another fossil from the animal) might support
your hypothesis about these fossils?
• What new piece of evidence might prove that your interpretation of these fossils is
inaccurate?
LAB:
The Great Fossil Find Lab

19. A HISTORY LESSON:
Charles Darwin: 1809- 1882, naturalist who
voyaged on the HMS Beagle as a young man & is
know as the founder of the idea of natural selection
later in life…
…really a THINKER, who put
together the ideas of many
contemporaries.
www.victorianweb.org/science/darw
in/index.html

20. •He collected plant and animal samples, esp. off
the coast of Ecuador in the Galapagos Islands
http://upload.wikimedia.org/wikipedia/commons/4/42/Voyage_of_the_Beagle.jpg
VIDEO:
Galapag
os Island
3 min

21. •Noticed that plants and animals on the islands
looked similar to those in Ecuador with minor
variations (differences)
•This got him to thinking
The beaks were
suited to what
the birds ate on
each island!
: www.biology-
online.org/2/11_natural_selection.htm

22. •traits- specific characteristics that can be
passed from parent to offspring through genes
•Genes-
•An example:
•Selective breeding- humans select desired
traits in plant/animal and breed it for more
(150+ breeds of dogs)
•What is DNA? HSW VIDEO DNA Videos 3 min
Understanding Genes: HSW VIDEO 3 min

23. •Thomas Malthus wrote An Essay on the
Principle of Population: an essay that said
humans had the potential to reproduce too fast
for the food supply
•Said that human populations are LIMITED to
choices humans make & available
resources/disease

24. Malthus POPULATION EGG CARTON STUDY
READ Book: The Global Village
Add popcorn kernels to the rows as follows:
TOP Food Supply: 1, 2, 3, 4, 5, 6
BOTTOM Human Population: 1, 2, 4, …

25. •Darwin thought then, that populations of all
species were limited:
•Starvation
•Disease
•Competition
•Predation
•So, only a limited number survive to reproduce
What was special about the survivors?

26. •Offspring inherit traits to survive in the
environment
•Darwin thought species could evolve over time
***MOST geologists at that time thought the Earth
wasn’t old enough for that
What was special about the survivors?
VIDEO: Evolution Adaptation 2 min

27. •Charles Lyell a geologist, wrote Principles of
Geology; said Earth was formed by natural
processes over a LONG period of time
•Darwin struggled with ideas for 20 yrs
•Alfred Russell Wallace 1858 a naturalist, writing
to Darwin; shared the same ideas
•1859 Darwin published his ideas: On the Origin
of Species by Means of Natural Selection
VIDEO HSW Charles Darwin & Evolution2

28. • Natural Selection process by which individuals
are better adapted to survive and reproduce than
others & pass along those genes to offspring
• Theory lacked some evidence, but later
scientists filled in the holes
1. Overproduction: producing more potential babies
than will survive
2. Inherited variation: each individual is slightly
different, not exactly like parent
3. Struggle to survive: some will die, disease,
competition, predators, but ALL won’t
4. Successful reproduction: those most adapted to
environment will have offspring with traits like them
ADVANCE
•PICTURE
VIDEO 1 Evolution of organic life 2min VIDEO 2 Natural Selection 2 min

29. B
A
C
K
A
D
V
A
N
C
E
Textbook:
HoltScience&Technology6thGrade

30. Natural Selection
NEXT

31. BACK
http://evolution.berkeley.edu/evolibrary/
article/bergstrom_02
CC VIDEO: #14 Natural Selection (12 min)

32. •Tusk-less elephants are proving
beneficial against poachers &
are living to reproduce offspring
without tusks as well
EXAMPLES:
African Elephant
http://www.wildlife-pictures-
online.com/elephant_epkp4.html
HSW- LINK (elephant evoln) 4 min

33. •During Industrial Revolution,
soot covered the trees in
Europe. White moths stood
out & were eaten; black moths
reproduced & white moths
almost gone
EXAMPLES:
Peppered moth
http://sisu.typepad.com/sisu/pepperedm
othslichen.jpg
www.amentsoc.org/about/news/0111/
http://radaractive.blogspot.com/2009/07/in-regards-to-canards-
natural-selection.html

34. •Pesticide
resistance:
resistant
individuals live to
reproduce &
pass on resistant
genes. Insects
produce LOTS of
offspring
EXAMPLES:
http://www.grapes.msu.edu/images/pesticResist.
gif
www.grapes.msu.edu/pesticideResist.htm

35. •Super viruses
•Same flu shots not work each year
•Antibiotic resistance
EXAMPLES:
virusBacteria: staph
www.healthheap.com/tag/bacteria
http://health.howstuffworks.com/medicine/mo
dern/light-virus.htm

36. •Speciation formation of a new species; species
become so different, they can’t mate any longer
•Separation new adaptation can’t
mate when go
back to
original
population
SEPARATORS:
Canyon
Mountain range
Lake
humans
Textbook:
HoltScience&Technology6thGrade
CC VIDEO: Speciation of Ligers & Men (12 min)

37. VIDEOS:
Discovery Education: Greatest Discoveries with Bill Nye: The
Origin & Evolution of Life pr25173 45 min DISC LINK
HSW- LINK (evolution) 20 min
Earth’s geologic History LINK (30 min)
CC #20 Evolution: It’s a Thing (12 min)
CC Big History: #6 Human Evolution (12 min)