T. A. Blakelock Grade 11 Biology
Evolution
Name:
Period:
Class:
1
UNIT 2 EVOLUTION
A. THE ORIGIN OF LIFE
1. The Early Earth
a. the earth was formed about ___________ billion years ago
b. it was _________, volcanic and bombarded by particles & __________ rays from space
c. it took about ____________ million years to settle down
2. Early Life
factor
a. Factors needed for early life
What was available on the early Earth
_____, _____, _____ and _____, were in the atmosphere;
Basic organic
molecules
in the lab, adding __________ & a ____________ to these gases in a
Miller-Urey apparatus will result in __________ & other molecules of life
certain types of ____________ converts ___________
Organizing basic
organic molecules
Energy source
carbon-based molecules to _____________ ones at hydrothermal vents
_____________ energy; _________________ energy provide lots of energy
____________________ will spontaneously form
Protective capsule
______________________ which are double layered membranes
Reproductive
molecule
__________ can reproduce without any enzymes because of an effect
called _________________
b. Threats to early life
Threat
strong UV LIGHT – no ozone
[DNA can only reproduce with enzymes]
How early life coped by living in the ocean
_________________ stops UV light
use deep sea vents as source of
If they avoid UV light, how do they
get enough energy
__________________ therefore early life
has to be ________________________
EXTREME TEMPERATURES – lots
of volcanoes
DESSICATION – low atmospheric
pressure so air very dry
3. Significant events in early life
water ________________ temperature changes
although it remains at temperatures over _________
water is _________________
see Timeline
2
3
4.0 by
3.0 by
2.0 by
prokaryote with
__________ membranes
_______ abundant in
the atmosphere
0.0
1.0 by
endosymbiotic life
_____________ lifeforms
with __________
the first __________ life
forms
endosymbiotic life
with ___________
600 my
500 my
400 my
300 my
200 my
100 my
0.0
___________ on land
early
dinosaurs
_________ appear
_________
invertebrates
first
_________ appear
first __________
_______
________fishes
__________ invade land
___________
appear
early
__________
first
________
___________
__________ invade land
__________ fish in seas
4
4. Mass extinctions
WHEN?
WHAT?
WHY?
_______ million
years ago
trilobites, brachiopods,
molluscs and echinoderms.
_______ million
years ago
Echinoderms, trilobites,
nautiloids but not as severe as
the last one
_______ million
years ago
_____% of all species vanished climate change, in this case a global _________, was
mostly in the sea and lakes
an important factor
_______ million
years ago
_____% of all marine species
were lost
_______ million
years ago
sponges, cephalopods,
brachiopods, insects and many
vertebrate groups
_______ million
years ago
____% of all species including
the dinosaurs, many fishes and
many plants either died out
completely or suffered heavy
losses
change in _______ level occurred at this time,
sea levels ____________ rapidly & the
beginning of the ___________
fluctuations in sea-level, a change in ocean
_________ and __________ activity plus climate
change
climate change seem to be important and, in
particular, an increase in _____________
a giant _____________ crashing into the earth,
severely disrupting the earth's ecosystem or
________________, climate change, environmental
pollution
B. Types of Fossils and Their Formation
INTRODUCTION:
A fossil is any evidence of a __________________ organism.
This includes casts, molds, footprints, track ways & feeding traces.
Ordinarily, only the _______________ parts of organisms are preserved (for example,
the __________ of invertebrates, & the _________ or __________ of vertebrates).
One of the keys to preservation is the absence of _______ & the presence of _________.
I. Body Fossils - actual ____________ or body parts of an organism are preserved, whether altered or not.
a. Unaltered Remains
-fossils which have undergone little or no change in ____________ and _______________.
-these are quite ________ as conditions to form them seldom occur
1. Encrustations -_____________ minerals in water form a thin crust on whatever lies in it.
When we dissolve away the encrustation, ________________________
This is usually __________________; Can study how organisms ____________________
5
2. Amber Entombment -insects may become trapped in ________, which may harden into amber.
We get original ___________________ We may be able to extract ___________________
If the insect has bitten a _________________________________________
3. Refrigeration -during the ______________ animals became trapped in ice.
This preserves lots of __________________
From this we may extract ______________________________
b. Altered Remains
As sediments become compressed by the __________ of overlying sediments,
they slowly undergo the process of ________________ [turning into stone].
1. Permineralization
-___________ in bones, shells, and plant stems become filled with mineral deposits.
We can see the _____________________, especially of _________________________
__________________ the original material is present so _______________
Usually we do not get __________________________
2. Replacement -____________ groundwater dissolves a hard structure in an organism
trapped in sediments & simultaneously _____________ a mineral
in its place--molecule by molecule.
-this results in fossils with a great deal of ______________.
Here we can see the feathers, or even see their ______________!
3. Recrystallization -conversion of the fossil usually to a new _______________
or to coarser crystals of the original mineral.
Crystals often form inside ____________________.
The lack of original material means ___________
The large size of the crystals mean we do not get ___________
4. Carbonization -under ________________ the volatile (liquid or gaseous) components are
forced out, leaving only a film of _______________.
Because of how they form, these fossil typically are of ______________
There are _____________ fragments remaining and only outside _________________
II. TRACE FOSSILS
1. Animal tracks
Can calculate the ___________ and therefore how the animal ___________
Also allows calculations of the ____________ of the animal.
6
2. Gastroliths -these are smooth, polished stones that helped herbivore dinosaurs ___________
vegetable matter in their ___________________
The surface ________________________ on these stones allow us to determine
the type of ____________________ eaten
3. Coprolites -fossil ____________ can be sometimes give definitive knowledge __________.
In carnivores, we find _____________________
and in herbivores we find ______________________________
III. DATING FOSSILS
1. few fossils can be dated __________________
2. the system depends on the rule that older things are buried _____________
3. this works by sediments being deposited over time by _____________
A
C
B
creature dies near site of
Dead creature is _________ over time, remains of newer
__________ and parts do
& other creatures die
dead creatures are buried
not decompose
in same area
____________ older remains
SOIL SURFACE
1. We know that A is ___________ than
volcanic ash # 1
A
2. We know that B, C and E are ________
VOLCANIC
ASH # 1
VOLCANIC
ASH OR
LAVA # 2
than volcanic ash # 1 and ________
than volcanic ash # 2
C
B
E
D
3.
We know that D is _________ than
volcanic ash # 2
4.
We assume that C is ________ than B
and E because it is shallower
5. We assume that B & E are the ______ age
by distance above volcanic
ash # 2
7
C. RADIOMETRIC DATING
1. Radio-isotopes --- atoms that decay with a set _______________
2. half life --- time required for ½ of the ________ isotope to decay to a _________ isotope
_______ % PARENTAL ISOTOPE
______ % DAUGHTER ISOPTOPE
%
P
A
R
E
N
T
A
L
I
S
O
T
O
P
E
75
______ % PARENTAL ISOTOPE
______ % DAUGHTER ISOTOPE
50
____ % PARENTAL ISOTOPE
____ % DAUGHTER ISOTOPE
25
_____ % PARENTAL ISOTOPE
_____ % DAUGHTER ISOTOPE
12.5
______ % PARENTAL ISOTOPE
______ % DAUGHTER ISOTOPE
_____ % PARENTAL ISOTOPE
_____ % DAUGHTER ISOTOPE
¼
½
1
2
3
4
5
half lives of the isotope
6
4. Examples of commonly used isotopes
PARENTAL
ISOTOPE
DAUGHTER
ISOTOPE
carbon – 14
14
potassium – 40
40
uranium – 235
235
C
K
U
HALF LIFE
in years
RANGE in years
nitrogen – 14
14
N
100 – 100000 yrs
argron – 40
40
Ar
100000 – 4.6 billion
lead – 207
207
Pb
Best for
10 million – 4.6 billion
5. What age are the following?
a. 3.125 % of the original 14C remains.
b. 87.5 % of the original 40K remains.
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Questions on the relative age of fossils.
Soil surface
E
Volcanic ash #1
A
I
B
C
Volcanic ash #2
F
J
D
Volcanic ash #3
K
G
L
H
Researchers have found 12 fossils in an area where there have been three volcanic ash deposits over time.
There is also evidence of an earthquake as all three ash layers have a split in them.
Samples of volcanic ash #1 shows that only 0.78125 % of the 40K has decayed into 40Ar.
Samples of the rock at volcanic ash #2 shows that 3.125% of the 235U has decayed into 207Pb.
Samples of volcanic ash layer #3 indicate that 96.875% of 40K still remains.
1. Show your calculations for the ages of each volcanic ash layer.
[6 marks]
2. EXPLAIN the relative age of each of the 12 fossils found.
[12 marks]
3. EXPLAIN which fossil will cause the researchers the most problem in aging,
either relative age OR absolute age.
[2 marks]
4. EXPLAIN for which fossil(s) we can most accurately determine the actual age.
[2 marks]
5. EXPLAIN for which fossil(s) we can determine very little about the actual age.
.[2 marks]
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D. DARWIN, WALLACE and OTHERS
1. PRE-DARWIN
a. pre – 1700’s: the Bible was taken as fact and the earth was only _________ years old,
_______________ since God created it
b. 1700’s:
people started to study the earth and find _________________,
noticing that ________________ happened over time
c. Cuvier – 1700’s: - catastrophism
– series of God sent _________________ had changed earth
Hutton – late 1700’s - actualism
– slow processes such as _______________ changed the earth
Lyell – early 1800’s - uniformitarianism
i] the past & present are ruled by the same _______ & forces
ii] geological change is very __________ [earth millions of years old]
d. biological theories before 1850
i] God created life ________________
ii] Buffon & Erasamus Darwin said that life ______________ over time
– from a ____________ species to _____________ species
iii] Lamarck – life changed because it _________________ traits
and then ________________ these traits to the next generation
eg. a giraffe stretches to get food
its offspring will be born with longer necks
2. DARWIN and WALLACE
Darwin
-well ______________
-well __________________
-young & _________________________
- careful _____________________________
-lots of time to _____________________
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HMS Beagle -____ year trip around the _______________
- Darwin as a __________________ companion & then as a _________________________
- stopped many places in ______________________________
- noted pattern of life ________________________ as he went south
- found ______________ fossil species that resembled_____________ species there
Galapagos Islands
-____________________ islands 1600 km from South America
-very few ________ animals present; all of which arrived ___________
- each island had _______________________ with slightly different
beaks and feeding habits
- Darwin’s Finches: each had different ________ & different ________.
- the giant tortoises on each island had slightly different __________
and ate slightly different __________________.
Darwin back in England
-did more ______________________ on collected specimens for the next _____ years [1835-1855]
-every Royal Navy vessel that landed on the Galapagos was required to collect ____________________
& note _______________ they were shot.
-he was ____________________ of his own theories as they related to the ____________________
Galapagos finches
-each _________________ has unique finches
-finches ________________ match their diet
-mainland only has _______________ finch
-DARWIN thought that _____________ may have helped select
or shape the __________________ of the finches
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Wallace
- not well __________
-___________________ specimens he collected
- careful __________________
- visited ________________
Wallace observed
Sailing 1000km from Java to Bali, saw only _____________ eating large fruit with big seeds
After crossing 32km of ocean, at Lombok, saw only _____________ eating large fruit with big seeds
Wallace wondered:
why had God had created two such ___________________ birds to eat the _______________
large fruit on two islands that were right ______________ each other?
Wallace concluded:
the _____________________ had selected the best ____________________ bird [the hornbill] and
the best __________________ bird [the cockatoo] to match the same fruit
Darwin / Wallace each concluded:
-__________________ somehow shapes species
-species vary due to ______________________
12
Natural selection
Darwin & Wallace were both influenced by: ______________ – “Essay on populations”
key idea – more_________ occur than can be supported so only the ______ survive
Wallace wrote to Darwin
-they shared similar ________________
-Darwin was afraid Wallace would_________________ him
-they agreed to publish a_________________ 1855
DARWIN published: 1859
“On the Origin of ________________ by Means of Natural Selection,
or the Preservation of Favoured Races in the Struggle for Life.”
Reaction to “The Origin of Species"
_________________ fled to his country house and would see no visitors
___________________________ was a friend who agreed to speak for Darwin.
He became known as “Darwin’s __________________”
There was a famous evolution ____________________ on June 30, 1860
between Huxley and Bishop ____________________.
Bishop Wilberforce was ________________ the debate until he strayed into
Human Evolution. At some point he challenged Huxley about his __________.
Huxley responded that “I would rather be descended from an _________________
than from a ____________________ like you!”.
E. DARWIN’S EVIDENCE OF EVOLUTION
1. Fossils
- fit a _______________
2. Homologous structures
[pg 523]
similar structures doing very different functions
a. ___________ in adults
b. ____________ in embryos
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3. vestigial features [pg 525]
structures with ____________ in one organism but have a __________ in similar organisms
eg human ______________,
whale ______________
4. artificial selection
a. ________________
b. _________________
5. Mechanisms of Darwinian Evolution by Natural Selection
ASSUMPTIONS
1. offspring _______________
2. some of this variation is __________________
3. more offspring are born than can ________________
4. populations generally do not increase in ________________
INFERENCES
1. individuals of the same species will ___________________
2. the survivors will pass on their ‘favourable’ ___________ to the next generation
3. over time, there will be more ___________ from the survivors in the population
6. Macroevolution vs Microevolution
Macroevolution – change to form new ___________
eg Darwin’s finches
this takes a very ___________ time [________________ of years]
Microevolution - change _________________ a species
this takes only a __________ time [_____________ of years]
eg bacteria _____________ resistance; weeds ____________ resistance
eg. peppered moths
-in this one species there are two ____________ of moth
-prior to industrialization the ______________ form was most common
-after industrialization, the _______________ form became the most common
-studies showed that _________________ selected the easier to find moths
EVIDENCE OF EVOLUTION # 1-7
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EVIDENCE OF EVOLUTION
Identify if it is evidence of ‘MICRO-EVOLUTION’[with-in a species], ‘MACRO-EVOLUTION’ or ‘NOT
EVIDENCE’ EXPLAIN your choices
1 For over 100 years, nicotine has been used on islands to control grasshopper populations. Nicotine is
a deadly poison that kills all animals exposed to it. Most islands where nicotine has been used now
have fewer grasshoppers.
2. The findings of ancient crocodiles, sharks and rhinos indicates that in the past, representatives of
these families were much larger than current species.
3. The proteins for eye lenses in moths, fish, cows, mice and frogs are all quite similar, with those from
mice and cows being the most similar.
4. When digging down into the earth, scientists encounter older samples at deeper depths. At 8.2
metres, no trees were found with seeds possessing coats. At 2.4 metres, all trees had seeds
bearing seed coats. At 4.7 metres, some trees had partial seed coats. [consider these depths!]
5. On most islands with heavy lead pollution from mines, few grass plants can grow. However, on some
islands with long term lead mining, researchers have noticed populations of grass growing quite
well.
6. A study of birds, bats and flies indicates that in the egg or womb they all show well developed eyes &
wings.
7. The fish in small lakes differ more from the fish in similar, but distant, small lakes than they do from
fish found in large lakes located nearby but not attached by rivers.
F. RANDOM CHANGE IN A POPULATION
evolution happens with ______________________, NOT individuals
we say that a population has ___________________ when it is different from the original population
in its allele_____________________ or genetic make-up
this difference in genetic make-up results from ____________ alleles being passed on to the next
generation in a ____________________ pattern
1. Genetic Drift
in small populations, alleles can be lost at __________________ from the population
eg. if there are two populations each with a _____________ allele at a frequency of 1%
in one population of 50,000 [_______ have it] and in another population of 500 [____ have it]
if some random event kills 20 % of the population it may kill the _______ who have it,
but is unlikely to kill all of the ________________ in the larger population
15
1b. Bottleneck Effect
this is a large, usually temporary, _______________ in the population that
usually results in a significant genetic drift
eg. there were once ____________ elephant seals but we hunted them
by the 1890’s there were only _____________ elephant seals
now there are ____________ elephant seals and all are descended from
the ____________ so much genetic __________________ was lost
eg. cheetahs were once captured by Romans to use as ________________ pets
now if we do skin transplants among these cheetahs,
all __________ Africa cheetahs _____________ foreign tissue which implies limited diversity
with __________ African cheetahs, we see lots of ______________ implying diversity
1c. The Founder Effect
this results when a small population___________________ a new area,
again causing a limited number of ___________ to be present which is a form of genetic drift
eg.
1990 a video camera noted the arrival of ________________ from a floating log onto
one of the islands in the Caribbean that previously had ________________ of this species
there were 5 lizards, 3 ____________ and 2 ________________ all of the
_____________________ will from these 5 animals and so will differ at
_______________________ from related lizards on other islands
2. Gene Flow
often animals live in __________________ colonies; however, once a year, _____________ are
______________ of the home colony and move to a new colony [eg lions] depending on the
species, ______________ may be driven out instead [eg bees]; in either case, these individuals
bring their ____________ with them and will likely ________ the genetic balance in the new colony
3. Mutation
the random process of making ____________ in alleles themselves most mutations appear to be
___________ [no visible change] or ____________ but a very few will be _________________.
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3b. Gene Duplication
a segment of a chromosome or a single gene is accidentally ________________
during DNA replication
this duplication has no ________________ effect, positive or negative
Possible benefits of gene duplication
the organism now has a ________________ copy of a gene
so that when a change is made, in the duplicate a _________________ copy remains
if the change produces a _______________ useful protein, the organism still has the original and
so does not _____________________
if the change produces a ____________ useful protein, then organism directly ______________
G. TYPES OF SELECTION
in all populations, individuals are born in which there is a _______________ in the size of a trait
if there was _______ selection, the population would become more and more __________ over time
in theory, you could have a _______________ in which both an elephant and a weasel were just two
extremes of the same species this does not normally happen, due to ________________
for specific traits in a population
range for the trait
frequency of
individuals in
the population
with a trait
mean value for the trait
17
1. Stabilizing Selection
this is the most ____________ form of selection in which the extreme values for a trait are
selected _________ over time,
the mean of the populations remains _____________ , but the range is _______________
2. Directional Selection
selection___________________ one of the extremes and so over time the population mean
shifts ________ or ___________ and the range generally ________________ a bit
3. Disruptive Selection
selection favours both of the __________________ in a population and so the result is
_______________ populations each with an _____________________ mean
and a ______________________ range
18
4.
Sexual Selection
Human Beauty
Some of the benefits to attractive looking people are:
-their partners tend to be more _______________________;
-they are thought to be more ___________________ and sociable by their teachers
who tend to give them ___________________ grades in school;
-the _________________ tend to treat them more leniently.
Good looks were a sign of being __________ and relatively _____________free. Research shows
that even _____ month old babies stare at photos of the faces of _____________ people
__________________ than at photos of unattractive people.
____________________ in men is attractive-it suggests dominance, status, and power and
therefore the possibility of resources.
Those faces considered to be the most _________________ are typically those which have the
greatest number of facial features _______________ to any particular culture/race.
It is thought that the typically _________________ is attractive because this suggests
something which has ___________ to its environment and is _______________.
SELECTION by the FEMALE # 8 –10
In many species, the female selects a mate based on characteristics that she perceives will help her
offspring. In each of the situations below, the female selects the ‘b’ male. EXPLAIN why she does so in
each case.
8. Peacocks:
a] the male has a short tail, is not brightly coloured and flies well, hiding from
or avoiding most predators
b] the male has a long tail, colourful body and flies poorly, getting chased by
more predators and having a high fatality rate
9. Cheetah
a] The male stays with the female and attempts to help raise the young
b] The male impregnates the female and then immediately moves away
10. Squirrels
a] The male spends some time keeping a small area free from competitors and
eats quite well, keeping itself vigorous
b] The male spends all its time keeping a very large area free from competitors
and eats poorly, letting itself get run down
19
H. REPRODUCTIVE ISOLATING MECHANISMS
in order for one population to become very __________________from another, they must be
reproductively _____________, this means that there will no longer be a free exchange
of _________________ between the two populations
there are Prezygotic mechanisms that prevent ___________ or ______________
and Postzygotic mechanisms that prevent development of a ___________________
1. PREZYGOTIC MECHANISMS
a. Ecological Isolation
two populations do not exchange ___________ with each other because they are in different
______________ places or at different places within the same ________________
eg. _____________ and ___________ do not meet because one is in Africa and one in Asia
eg. Asiatic lion and Bengal tiger are both in northern India, but lion is on _______________
and tiger in _________________
b. Temporal Isolation
two populations do not exchange alleles because they are only _______________ to
exchange alleles at different __________________ of year or even of the day
eg. morning glory opens its flower at __________; cactus opens its flowers at ___________
eg. purple finch mates in __________ so babies have access to lots of berry seeds;
goldfinch mate in ___________ so that babies have access to lots of thistle seeds
c. Behavioural isolation
two populations do not exchange alleles because they do not _______________
to each others ______________ rituals
eg. male grey crickets rub legs at ___________ times a second and male black crickets
at ________ times a second the females of each species only ____________ to
the sound made by the male of that same species
20
d. Mechanical Isolation
two populations do not exchange alleles because of some physical ____________ that prevents this
eg. many insects have modifications on their _______________ such that the male and
female parts are a perfect ________________ fit
eg. orchids are shaped so that only certain beetles can reach the _________ and therefore pick up
the ________, that beetle will the go to another orchid of the same type to deposit the pollen
e. Gametic isolation
two populations exchange sperm and eggs but __________ markers prevent the eggs from
being fertilized by the ______________ sperm and so no alleles are exchanged
eg. wind blows the pollen of _______ onto the flowers of _________, but the pollen can not
grow down through the stigma because it does not possess the correct _________
eg. clams and fish both shed eggs and sperm into the same ________, but the clam sperm
can not penetrate the fish eggs and vice versa, due to_______________ not being
able to eat through zona pellucida
REPRODUCTIVE ISOLATING MECHANISMS # 11-17
Identify the type of reproductive isolating mechanism and EXPLAIN your choices.
11.
Two snake populations share an over-wintering burrow and eat the same diet, but mate at different
optimal temperatures.
12.
Two grasshopper populations are different in colour & so do not share the same predators, one
grasshopper type eats tree leaves & one eats grass leaves.
13.
Two turtle populations share a pond & general diet; but the female of one type has a tall shell and
the other a flat shell; the male of the first has a hollow in its lower shell, the second male has
a flat lower shell.
14.
Two sparrows populations share a similar diet, winter in different places but share mating & breeding
grounds with one type singing from the tops of trees and one type from small bushes.
15.
Two vole populations hibernate in different places, occasionally mate but the sperm & egg do not
fuse.
16.
One short, bushy, red hibiscus flower type is pollinated by bees and a tall, white hibiscus is
pollinated by hummingbirds
17.
One hawk type returns north in April and builds a new nest in mid-May, a second hawk type returns
north in mid-May and uses an old nest at that time.
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2. POST-ZYGOTIC ISOLATING MECHANISMS
a. Zygotic mortality - even though the zygote is created, it fails to __________ to maturity
b. Hybrid inviability- even though the hybrid is born, it does not live long or is not as ____________
c. Hybrid infertility - even though the hybrid is healthy and vigourous, it is not able to ___________
eg. donkey X horse --> healthy, strong mule but mules are sterile
3. SPECIATION
when two populations become completely ____________ and no longer exchange
____________, they are said to have formed separate ______________
a. Allopatric speciation - this is a situation in which the two populations are geographically
___________ prior to them becoming separate species
b. Sympatric speciation - this is a situation where the two populations remain in _______________
with each other but still stop exchanging alleles and become separate species
I. DIVERGENT and CONVERGENT EVOLUTION
1. Divergent evolution
results from two or more species evolving increasingly different __________ as a result of
_______________ selective pressures
this is what we classically think of as _____________: start with one cat and over time
get tigers, lions, leopards, cheetahs, jaguars, pumas, bobcats, ocelots etc.
2. Convergent Evolution
results from two unrelated species being subjected to _____________ selective pressures
with the result that they produce ________________ phenotypes
eg.
_____________ are a bony fish, ______________ are a mammal
but sharks and dolphins both ________________ fish in the open ocean
as a result, both have a similar body __________ and similar type and number of fins
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eg.
in Australia there never were any ______________ mammals so all of the niches
had to be filled by marsupials, many of whom greatly _______________ their
placental mammal counterpart
pg 603 shows equivalent species
J. NATURAL SELECTION
1. when a new allele arises in a population, one of three fates awaits it
a. if it confers an advantage, _____________ of the allele will appear in the population
b. if it conveys a disadvantage, ______________ of the allele will appear in the population
c. if it has no effect on survival, it will _______________ at its current level
2. alleles that confer an advantage must affect one of the following:
a. increase the __________________ of offspring with this allele that survive until they
are of _________________ age
b. increase the survival of _________________ with this allele even though children
may be _________________
c. increase the survival of ____________ with the same allele such as nephews or nieces
3. alleles that confer a disadvantage may take several forms
a. directly __________________ the number of offspring born
b. reduce the __________________ of offspring that reach reproductive age even while
increasing the number _________________
c. keep the allele in a ______________ population such that random chance is more likely
to completely __________________ all of those individuals with the allele
NATURAL SELECTION # 18-25
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NATURAL SELECTION - nature selects for alleles in populations.
If the allele is passed on in large numbers, it is successful regardless of how odd the phenotype may seem
to us. Some allele will become more common and some less common through the selection process.
SELECTION IN EARLY HUMANS
[Assume all traits are like modern humans unless otherwise stated]
If an allele is selected for, it will produce a population with: ‘MORE of ALLELE’; if an allele is selected
against, it will produce a population with ‘LESS of ALLELE’, and if an allele is neutral in effect it will produce
a population with ‘SAME amount of ALLELE’. Identify which of these will occur for # 18 – 25 and EXPLAIN
for each: Be sure to consider all of the aspects outlined on the previous page.
18. A new allele causes females to have children every 18 months instead of every 27 months.
19. A new allele reduces human life span to 40 years.
20. A new allele causes females to pretend to be monogamous, but she has [the same number] of
children with several different fathers.
21. A new allele causes males to shun hunting with their brothers and choose to hunt with non-relatives.
22. A new allele causes males to frequently scold and yell at children and partner.
23. A new allele causes females to continue ovulation well past 60 years of age.
24. A new allele causes males to become infertile at age 45.
25. A new allele causes females to kill all of their very sickly children.
24
K. RATES of EVOLUTION
1. Theory of gradualism
a. ____________________ changes result from many small changes
b. this implies there should be as many of the ________________ form as of the final forms
c. the evidence is that there are few _______________ forms
2. Theory of punctuated equilibrium
a. large changes happen relatively ___________________
followed by long periods of little or no _____________________
here ‘rapidly’ refers to 100,000 years or a 1000 ________________________
b. this corresponds to large and sudden changes in the ______________________
c. ex. 65 million years ago the ________________ disappeared and we saw lots of new
_______________________ in a short period of time
MODEL
gradualism
puncuated equilibrium
no change
in both models, the time of change from box to circle is the ____________________
but.....in punctuated equilibrium the actual change was more ___________________
and the transition forms[hexagon & octagon] are less ___________________
as they are around for less ______________________
L. PHYLOGENY - the theoretical evolutionary ______________________ of a species
1. Cladogram – diagram depicting the proposed evolutionary ____________________ of a
group of species
- these are also called phylogenetic____________ or family___________
25
a. example 1
A is the common ancestor of all _______________________
B is the common ancestor of all land ___________________
C is the common ancestor of all ________________ shell laying animals
D is the common ancestor of all animals with ___________ covering some or all of body
E is the common ancestor of all animals with a single opening in side of __________
F is the common ancestor of all animals with ‘___________-like’limb bones
RAY-FINNED FISHES
AMPHIBIANS
TURTLES
CROCODILES
BIRDS
DINOSAURS
MAMMALS
TIME
PRESENT
note that all _______________ species end up at the same point on the page eg. dinosaurs are __________
the length of the line indicates how long it has been since the species ___________________________
b. example 2 pg 608 and 609 builds another caldogram
note that all living species end up at the same point on the page
the length of the line indicates how long it has been since the species branched off
c. pg 609 TRY THIS do this as exercise
d. Using Genetic Evidence
pg 611
e. there will be an in class [work on your own] assignment on this
26
CLADOGRAM WORKSHEET
1.
Construct a simple cladogram based on the table below.
TRAITS
thylacine
Lamprey
Rhesus
monkey
placenta
Bullfrog
X
paired appendages
X
X
Human
Snapping
turtle
Tuna
X
X
X
X
skull atop spine
X
X
paired legs
X
dorsal nerve chord
X
amniotic sac
X
mammary glands
X
species is extinct
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
2. The example below makes for a more complex cladogram, that will require more planning to
ensure that the set up works out logically.
TRAIT
COW
covered in hair
X
has keeled sternum
ROBIN
WOMBAT
OSTRICH
X
has placenta
X
eggs with no shell
FROG
RAT
X
X
X
X
X
X
X
X
X
covered in feathers
skin must stay moist
HORSE
X
rotates shoulder joint
has vertebrae
HUMMING
BIRD
X
X
split hooved
has hooves
TOAD
X
X
X
X
X
X
X
X
X
X
X
X
X
27
Restriction Map of Human and Various Primate DNA in a Cluster of Genes Coding for Hemoglobin Elizabeth
Zimmer and Alan Wilson developed the map reproduced below (as cited in Alberts, et al. Molecular Biology of the
Cell. Garland Publishing, 1983).
From the following list, predict which are the most and which are the least closely related: human, chimp, pygmy
chimp, gorilla, orangutan, and gibbon.
A difference in the maps above exists if the
LETTER for the allele is moved, or is absent in
the ‘ape’ compared to the human pattern
Compare each map to humans and determine the
number of differences.
Use that to complete the cladogram to the right.
Questions
1.
2.
3.
4.
5.
Hemoglobin is the molecule in the bloodstream which transfers oxygen from the lungs to the body's cells; it is, therefore,
important that it work properly. Is an animal born with large changes in its hemoglobin likely to survive to produce
offspring? Reason?
Some small changes in the hemoglobin molecule may give an animal an advantage in one environment and a
disadvantage in some other environment. Are these sorts of changes likely to accumulate in the hemoglobin gene over
long periods of time, or be changed back and forth as the outside environment changes? Explain.
Some small changes in the hemoglobin molecule are selectively neutral--they do not affect the animal's fitness in any
change of environment. Are these sorts of changes likely to accumulate in the hemoglobin gene over long periods of time,
or be changed back and forth as the outside environment changes? Why?
Of the three sorts of change introduced in questions 1 - 3, which sort is the most likely to accumulate in the hemoglobin
gene from generation to generation?
If the changes we are counting are a) random, b) selectively neutral, and c) tend to persist in the genes from generation to
generation, would you expect the genes of two closely related organisms to have more differences or fewer differences
than the genes of two distantly related organisms?
28
M. Early hominid evolution
Lemurs, lorises, pottos
tarsiers
New World Monkeys
Old World Monkeys
Gibbons
Orangutans
50
40
30
20
10
0
MILLIONS OF YEARS AGO
Proconsul heseloni
Distribution of species
______________________
Date of specimen
About ___________________
Cranial capacity
_________________ than chimpanzee, about 320cc
CHANGES in PRIMATES
WHERE?
________________
WHEN?
________________
WHY?
________________
29
CONDITIONS in AFRICA
- _______________________________
-land is covered in ___________________
-much of Africa then was like ______________ is now
PRIMATES PRESENT THEN - monkeys living in __________________
- -apes living in ____________ or on the _____________ under the trees
- lots of ______________, lots of _______________, BUT lots of ___________________
CHANGING CONDITIONS
-6 my BP, East Africa became ___________________
-forests began to _______________________
-food ran ___________________ and some primates had to ___________ the forest or ________
OPEN LAND PRIMATES
eg. modern baboons
-live in _________________
-search for food by _______________
-return to trees for safety _____________________
FOOD TO EAT…..as herbivores?
- quality of food is _______________
- availability of food is ______________
FOOD TO EAT – as carnivores?
-what is out there?
-how to catch it?
-how to kill it?
COMPETITION
SOLUTION
____________ and _______________
Use your _________________
30
The ancestors of Homo sapiens sapiens
Sahelanthropus tchadensis
Lived
6-7 million
Range
Diet
Range
4.2 – 3.9 million
3.9 - 3.0 million
Australopithecus africanus:
million
Fruit, nuts, seeds, tubers
insects.
Soft fruit, nuts, seeds, tubers
and bird eggs.
Noticed canines, large
molars .protruding jaw
less than 100 cm
cm; sexes differ
cm
small canines, large molars;
protruding jaw
150 cm; sexes differ 30 cm
cm; sexes differ
cm
150 cm; sexes differ 20 cm
30% / no crest
none
Paranthropus aethiopicus:
Lived
Australopithecus afarensis:
East africa
_____ plants
less _____ than chimpanzee
Brain size
Sagittal crest
Tools
million
Australopithecus anamensis
East Africa
Jaw
Size
Ardipithecus ramidus
million
Ethiopia
38 % / no crest
none
none????
Paranthropus boisei:
Paranthropus robustus
2.3 - 1.2 million
1.9 – 1.0 million
East Africa
Jaw
No canines, massive
molars protruding jaw;
Size
130 cm; sexes differ 10 cm
cm; sexes differ
Brain size
Sagittal crest
37% / crest
Tools
none
Homo habilis:
million
Homo rudolfensis:
2.2 – 1.9 million
East, south Africa
Nuts, tubers, termites,
possibly papyrus
rhizomes.
Diet
simple rock
cm
Nuts, tubers, termites,
possibly papyrus
rhizomes.
No canines, massive
molars protruding jaw
Omnivorous diet
including scavenged
meat
chiseled incisors;
medium molars
140 cm; sexes differ 10 cm
131cm; sexes differ 10 cm
cm; sexes differ
cm
47 % / no crest
complex, shaped stones
31
Homo ergaster
Homo erectus:
Lived
Range
Homo heidelbergensis:
1.8 million - c.30,000
all of Africa
Omnivorous with
quantities of meat.
chiseled incisors small
molars
Size
Tools
East Africa & ??
Relied heavily on meat.
chiseled incisors; small
molars
180 cm; sexes differ 20 cm
Brain size
Sagittal crest
/ no crest
75 % / no crest
complex, shaped stones
Homo sapiens idaltu
230,000-28,000
Africa, Europe.
Diet
Jaw
Homo neanderthalis:
chiseled incisors; small
molars
166cm; sexes differ 10 cm
/ no crest
very complex, shaped
stones for many
purposes
100% / no crest
stone, wood, bone, antler
tools including bows
Other changes in Hominids over time
The pelvis _______________________
as our ancestors became bipedal
The feet became__________________,
with the_______________ less widely spaced
and with a broader _____________
to assist bipedalism
32
Human Evolution Summary
Changes from earliest Hominid to Australopithecus
Trait
Trend
Time
Range
Diet
Teeth & Jaw
Sagittal crest
Height
Brain size
Tools
Changes from Australopithecus to Paranthropus
Trait
Trend
Time
Range
Diet
Teeth & Jaw
Sagittal crest
Height
Brain size
Tools
Changes from Australopithecus to Homo
Trait
Trend
Time
Range
Diet
Teeth & Jaw
Sagittal crest
Height
Brain size
Tools
33
34