Monday 2/8/2016
Agenda: Evolution Part II
 Activity: Darwin’s Natural Selection Worksheet
 Notes: Rate of Evolution
Homework/Class Work:
No Homework Tonight….unless…….
Start: Q3 WK4 D4&5
Darwin’s Natural Selection
Worksheet
Q3 WK4 D4&5
The Rate of Evolution
Different kinds of organisms evolve at
different rates
Bacteria evolve much faster than complex cells
The rate of evolution also differs within the same
group of species
In punctuated equilibrium, evolution occurs in
spurts
In gradualism, evolution occurs in a gradual,
uniform way
Punctuated equilibrium
Gradualism
GRADULISM
PUNCTUATED
EQUILIBRIUM
Evidence of Evolution
1. Fossil Records
2. Molecular Records (Carbon Dating and DNA)
3. Anatomical Records
Fossil Records
Fossils are the preserved remains, tracks, or traces
of once-living organisms
Fossils form when organisms become buried in
sediment and calcium in hard surfaces mineralizes
Arranging fossils according to age often provides
evidence of successive evolutionary change
Robert Hooke in 1668- 1st to propose that fossils
are the remains of plants & animals.
Provides the most direct evidence for
macroevolution
Missing Links
Ardi (Ardipithecus ramidus) : stood about 47
inches tall and weighed about 110 pounds.
Took 15 years to unearth.
Lived 4.4 million years ago
Lucy (Australopithecus afarensis) : 40 % complete skeleton.
Lived 3.2 million years ago


Fossils have been
found linking all
the major groups
The forms linking
mammals to
reptiles are
particularly well
known
Fig. 13.4 Whale
“missing links”
More Missing
Links
Archaeopteryx. The most primitive known
bird. Lived ~150 million years ago.
Ambulocetus: The walking
whale. This animal could walk
as well as swim. It lived ~50
million years ago.
Tuesday 2/10/2016
Agenda: Evolution Part II
 Notes: Fossil Records
 Activity: Radioactive Dating Worksheet
Homework/Class Work:
Radioactive Dating Practice Worksheet due
Wednesday/Thursday 2/10-2/11/2016
Fossil Records
• Relative Dating (aka Law of
Superposition) by Nicolaus
Steno
• By looking at where the
fossils are in relation to the
rock depth or layers,
scientists can see when an
organism goes extinct or
when there is a mass
extinction
• In other words, in a cross
section of the Earth or rock
layers, the lowest layer is the
oldest
Molecular Records
• Certain atoms are known to decay (break down) at a
specific rate. Scientists can look at these atoms to
determine how old an organic object is.
• Radioactive isotope 14C- gradually decays over time back to
14N (known as Carbon Dating)
• It takes 5600 years for half of the 14C present in a sample to be
converted to 14N.
• This length of time is called the half-life.
• Half life (t1/2): the time needed for half of the atoms of
the isotope to decay
• For fossils older than 50,000 yrs scientists use potassium
isotope
• t1/2 of 40K = 1.3 billion years to turn to argon (40Ar)
How do we use the method?
Uranium-235 has a half-life of 700 million years. How much of the 12 g sample of
Uranium-235 will be left after:
• a. 700 million years _______
• b. 1400 million years _______
Radioactive Dating
Practice worksheet
• Lets practice radioactive dating
• Attach into your sci. ntbk 
Wednesday/Thursday 2/10-2/11/2016
Agenda: Evolution II
 Review: Radioactive Dating Worksheet
 Activity: Dating the Iceman Worksheet
 Activity: Iceman Murder Mystery
Homework/Class Work:
 Finish Radioactive decay worksheet due Friday
2/12/2016
Radioactive Dating
Practice
Lets practice radioactive dating to better understand the homework:
How much of 20.0 grams of a substance will be left after 1 hour if the half life is
15 minutes (answer in grams)
The half life of thorium-27 is 16.32 days. How many days are required for 2.63 to
remain if you start with 84.25 grams?
Notebook Check
• Notes: Rate of Evolution
• Activities: Natural Selection of Cacti, Blood Donor
Mix Up Questions, Darwin’s Natural Selection
worksheet, Adaptations of Rabbits Foldable
Friday 2/12/2016
Agenda: Evolution Part II
 Notes: Anatomical Records
 Activity: Anatomical Records Foldable
Homework/Class Work:
Radioactive Dating Practice Worksheet due
Wednesday/Thursday 2/10-2/11/2016
Anatomical Record

Similar structural forms can be seen in
different living organisms
3.
Homologous structures
Analogous structures
Vestigial structures

All vertebrates share a basic set of developmental instructions
1.
2.
Relict
developmental
forms

Homologous structures: have same structure,
DIFFERENT function. However, the structures
are derived from the same part of a common
ancestor
The same basic bones
are present in each
forelimb
Fig. 13.8
Homology among
vertebrate limbs

Analogous structures: resemble each other as a
result of needed adaptations to similar
environments (Different animals adapt in similar
fashion when challenged by similar opportunities)
 The feature has the same function but looks
different.

Vestigial structures:
 Although the structure(s) had a purpose &
function in the past but they are largely or
entirely functionless now.
 a vestigial structure may retain lesser
functions or develop new ones.
The blue whale has tiny hind leg bones under its tail.
The blind mole rat has tiny eyes completely
covered by a layer of skin.