Transcript Chapter 30 Evolution

Chapter 30
The Theory of
Evolution
Evolution
• A process of change
through time
Brain Size????
• One of the most important advancements was the
increase in the size of the human brain. Although
this is not the only factor in our advancement as a
species it was crucial. Brain size is not alone the
most important factor. If this were the only factor
the blue whale would be the most advanced
technological species on Earth. It has been proven
that Neanderthal and Cro Magnon both had
similar sized brains. Yet Cro Maganon is
considered more advanced or modern due to it's
much more sophisticated use of tools.(technology)
Theory of Evolution
1. Suggests that existing forms of life
on earth have evolved from earlier
forms over long periods of time
2. Evolution accounts for the
differences in structures, function,
and behavior among life forms as
well as changes that occur in
populations over many generations
(I) Evidence of Evolution
Five observations supporting the theory of organic
evolution can be made through the study of:
1. Geologic record
– Ex: Similar fossils
2. Comparative Cytology
– Ex: similar Ribosomes, nuclei, mitochondria
3. Comparative Biochemistry
– Similar DNA, enzymes, Proteins
4. Comparative Anatomy
– HOMOLOGOUS structures: like wings and arms having similar
bones
5. Comparative Embryology
– Similar development, seeds and embryos (within eggs, or uterus)
(1) Geologic Record
1. Earth is between 4.5 to 5 billion
years old (age was determined by
radioactive dating of rocks)
2. Fossils- are the remains of traces of
organisms that no longer exist.
Fossils have been preserved in ice,
sedimentary rock, amber, and tar
(1) Geologic Record
Apatosaurus??
3. Other fossils have been formed from
petrification, a process by which the tissues are
gradually replaced by minerals that produce a
stone replica of the original material
4. Imprints, casts, and molds of organisms or parts
of organisms are frequently found in sedimentary
rock
5. In undisturbed layers (strata) of sedimentary
rock, the lower strata contain old fossils while the
upper strata contain younger fossils
4. Imprints, casts, and molds of organisms or parts
of organisms are frequently found in sedimentary
rock
5. In undisturbed layers (strata) of sedimentary
rock, the lower strata contain old fossils while the
upper strata contain younger fossils
Archaeopteryx:
a remarkable
fossil that has
provided
paleontologists
with insight to
the origin of
birds.
(2) Comparative Anatomy
1. Evidence supports that
similarities of basic
structures exist between
different organisms
2. Homologous structures
are anatomical parts
found in different
organisms in origin and
structure
3. The presence of such
homologous structures
suggest that these
organisms have evolved
from a common ancestor
(3) Comparative Embryology
• Although certain adult
organisms may be
different from each
other, a comparison of
the earl stages of their
embryonic
development may
show similarities that
suggest a common
ancestor
(3) Comparative Embryology
(4) Comparative Cytology
1. All living things are made up of cells.
2. Cell organelles including the cell
membrane, ribosomes, and
mitochondria are structurally and
functionally similar in most
organisms.
(5) Comparative Biochemistry
• All living things contain similar
biochemical compounds
• Examples :
– DNA, RNA
– proteins
– enzymes
Think of the Biodiversity lab
-Homologous
Structures
_______________
– Similar
Embryonic Development
_______________
– Similar DNA
_______________
– Similar Proteins
_______________
– Similar Enzymes
_______________
– Similar Pigments
_______________
Comparative Cytology
Comparative Biochemistry
Comparative Anatomy
Comparative Embryology
Evidence of Evolution
1. Geologic record
2. Comparative Cytology
3. Comparative Biochemistry
4. Comparative Anatomy
5. Comparative
Embryology
(II) Theories of Evolution
1. Attempts to explain the similarities
and differences among species
2. Adaptations- are a major component
to these theories. Adaptations are
features which make a species better
suited to live and reproduce in its
environment
(A)
Lamark
• The evolutionary theory of Jean-Baptiste
Lamark was based on the principle of:
1. Use and Disuse
2. Inheritance of acquired traits
Principle of Use and Disuse
• For an organism, new structures appeared
in the course of evolution because they were
needed.
• Structures that were present and were used
became better developed and increased in
size; structures that were not used
decreased in size and eventually
disappeared
Ex: muscles of an athlete vs. appendix
Inheritance of Acquired Traits
• Useful characteristics acquired by an
individual during its lifetime can be
transmitted to its offspring
• These acquired traits results in species
that are better adapted FOR their
environment
• Ex: a giraffe’s neck became longer as a
result of stretching to reach higher
branches. This acquired trait was then
passed down to the offspring
Inheritance of Acquired Traits
• Useful characteristics acquired by an
individual during its lifetime can be
transmitted to its offspring
• These acquired traits results in species
that are better adapted FOR their
environment
• Ex: How did giraffe necks became longer?
What would Lamark say?______________
_____________________________________
Lamark’s Giraffes
(B)
August Weisman
1. Did not agree with Lamark’s theory of
acquired traits
2. So how did he disprove Lamar's theory ?
__________________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
(B)
Weisman
1. August Weisman did not agree with Lamark’s
theory of acquired traits
2. In a series of experiments, Weisman removed the
tails of mice.
3. The mating of these tailless mice produced offspring
with tails of normal length.
4. Weisman removed the tails of these mice and
allowed them to mate.
5. Again, offspring were produced with tails of normal
length.
6. The acquired condition of “taillessness” was not
inherited.
(C) Charles Darwin
• Charles Darwin devised a theory of
evolution based on:
1. variations with in a population
2. natural selection
• Included in his theory were five
main ideas:
Charles Darwin, and his 5 main ideas:
1. Overproduction: to create more offspring then can
survive
2. Competition: Organisms compete for resources, ex.
Food, shelter and water
3. Survival of the Fittest (fitness): The organisms best
adapted “FIT” to an environment will survive
4. Reproduction : If an organism survives long enough
they may reproduce passing down there genes
5. Speciation: If species continue to past down “NEW”
genes then that species will change over time. Ex, his
finches and penicillin resistant bacteria
Galapagos Islands
Do Now 5/31
review book page 87 #s 1-15
Beaks of Finches Lab
Objectives:
• To identify which beak adaptation is most
beneficial.
• To identify which adaptation will be passed on
to future generations.
Beaks of Finches Lab
Materials
•
•
•
•
•
4 Tools (2 different pairs)
2 Aluminum Tray
2 Petri dishes
2 bags of ONLY Lentil Beans
2 bags of Mixed Beans, lentils and Lima Beans
Period 6
Beaks of Finches Lab
Int
Round 1
Svvd
Forceps 8
8
Cloth
7
Pin
Wrench 4
Tongs 4
6
2
2
Round 2
Svvd
Round 3
Svvd
Period 1Beaks of Finches Lab
Int
Round 1
Svvd
Round 2
Svvd
Round 3
Svvd
Forceps 8
8
Cloth
8
Pin
Wrench 6
Tongs 4
4
4
0
Period 8
Beaks of Finches Lab
Int
Round 1
Round 2
Round 3
Svvd
Svvd
Svvd
Forceps
8
8
8
8
Cloth
Pin
Wrench
6
4
0
0
6
2
6
0
4
0
4
0
Tongs
Beaks of Finches Lab
PEPPERED MOTH
Mutations Revisited
1. Overproduction
• Within a population, there are
more offspring produced in
each generation than can
possibly survive
2. Competition
• Natural resources; like food,
water, and space available to a
population is limited
• Because there are many
organisms with similar
nutritional requirements, there
must be competition between
them for the resources needed to
survive
3. Survival of the Fittest
• Variations among
members of a population
make some of them better
adapted for the
environment than others
• It is generally the bestadapted individuals that
will survive
• The environment is the
agent of natural selection
determining which
species will survive
4. Reproduction
• Individuals that survive and
then reproduce transmit these
variations to their offspring
5. Speciation
• The development of a new species
occurs as variations or adaptations
accumulate in a population over
many generations
This would be Darwin’s View of
Lamark’s giraffes .
DARWIN'S REPRESENTATION OF
EVOLUTION
Time line of Hominids
Niches
1. Sketch the following
2. Theorize Why Sparrows A-D
are successful at those
locations. (make something
up about their food)
3. Why can all of these
sparrows live in the same
environment?
4. What would happen if
sparrow E entered this
Environment?
Niches
1.
2. Variation of Food sought after.
3. Each species occupies such a
specific niche that there is no
competition for resources.
4. Direct competition the best fitted
would survive.
Niche + Competitions
• The diagram represents a tree containing three
different species of warbler, A, B, and C. Each
species occupies a different niche.
A fourth species, D, which has the same
environmental requirements as species B, enters the
tree at point X. Members of species B will most
likely
• (1.) live in harmony with species D
• (2.) move to a different level and live with species A
or species C
• (3.) stay at that level but change their diet
• (4.) compete with species D
(III) Modern Theories of Evolution
• The modern theory of evolution
includes both Darwin’s ideas of
variation and natural selection
and the current knowledge of the
sources of variations
(A) Sources of Variations
1. Genetic Shuffling:
• Segregation (during Meiosis)
• Crossing Over (during Meiosis)
• Recombination of alleles (during
sexual reproduction)
2. Gene mutation occurs
spontaneously and at random
(B)
Natural Selection
1. Natural selection involves the struggle of
organisms to survive and reproduce in a
given environment
2. Traits which are beneficial to the survival
of an organism in a particular
environment tend to be retained and
passed on, and therefore, increase in
frequency within a population
Do Now:
The graphic above shows that:
Do Now: ANSWER
The graphic above shows that:
–All of these primates had a common ancestor, the ancestral primate.
–The human and chimpanzee have the closest evolutionary relationship as
their DNA is the most similar.
(B)
Natural Selection
3. Traits which have low survival value to an
organism tend to diminish in frequency
from generation to generation leading
towards extinction.
4. If environmental conditions change, traits
that have low survival value may now
have a greater survival value. Therefore,
traits that prove to be favorable under
new environmental conditions will
increase in frequency
Adaptations
• An adaptation is a variation which assists an organism or
species in its survival.
• Biological adaptations include changes in structures,
behaviors, or physiology that enhance survival and
reproductive success in a particular environment.
Ex: Insects resistant to insecticides
1. How did insects become resistant to
insecticides?
• Include terms:
•
•
•
•
Overproduction,
Variations
Adaptation
Natural selection (selecting agent)
Ex: Insects resistant to insecticides
Insect resistance to insecticides:
• Insecticides kill insects not resistant to
the insecticide, while insects resistant to the
insecticide live to reproduce. The insecticide
acts as a selecting agent.
Bacterial resistance to antibiotics:
• Bacteria not resistant to an antibiotic are killed
by it, while resistant bacteria live to
reproduce. The antibiotic is a selecting agent
for these bacteria.
Ex: Insects resistant to insecticides
1. Genetic make-up of some insects make them resistant
to the effects of insecticides
2. Before the widespread use of insecticides, this trait was
of no particular survival value
3. With the increased use of insecticides, this trait
developed a very high survival value
4. Therefore, insects with resistance to insecticides
survived and reproduced much more successfully than
those lacking the trait
5. As a result, the frequency of insecticide resistance has
increased greatly in insect populations
Do Now:
• Why has this slow flying moth survived?
Do Now:
• Why has this slow flying moth survived?
• The Zaretis ellops (Holey Leafwing) looks like
leaf litter
Camouflage
•
•
•
•
•
Cryptic Camouflage:
Disruptive Markings:
Warning Coloration:
Mating Coloration
Mimicry:
– Batesian , bees and fly
– Mullerian, bees and wasps
– Automimicry, AKA extensive misdirection.
Why the mimicry??
• "Batesian" mimicry: Form of mimicry in which
an innocuous mimic species gains protection by
resembling noxious or dangerous model species.
1. Geographic isolation
ex: Pangea,
2. Reproductive isolation
(C) Geographic Isolation
•Gene frequency- the percentage of organisms in a
population that carry an allele
1.Isolation of a population increases the chances for
speciation (the development of a new species) by
separating a small group of organisms from the
main population with its large gene pool (inheritable
traits)
2.Changes in gene frequency are more likely to occur
in small populations than in large ones
3.Geographic isolation of a population is caused by
natural barriers like mountains, large bodies of
water, and deserts
Pangea and Continental Drift
http://www.scotese.com/pangeanim.htm
Pangea and Continental Drift
http://www.scotese.com/pangeanim.htm
Continental Drift
Geographic isolation leads to a
genetic drift.
A classic example of genetic drift can be observed in the
white-tailed deer population of Seneca Army Depot, an
11,000 acre reserve that was fenced off in the 1950s.
Security is tight and hunting is not allowed at this
ordnance depot. What is unusual is about this deer
population is that rare white-phased deer can be found in
significant numbers within the fenced in area. In 1993, it
was estimated that there were
150 albino deer and 300 normal colored deer.
Mountains Form
The evolution of an isolated population into a new
species may involve the following factors:
a) the gene frequency in the isolated population
may have been different than the gene frequency
in the main population to begin with
b) different mutations occur in the isolated
population and in the main population
c) different environmental factors may also have
exerted different selection pressures on each
population (natural selection was different)
(D) Reproductive Isolation
• If the isolated population becomes so
different from the main population that
members of the two cannot interbreed and
produce fertile offspring, then they have
become two distinct species.
(E) Time Frame for Evolution
• There are two different theories proposed
by scientists to address the rate of
evolution:
1. Gradualism- proposes that evolutionary
change is slow, gradual, and continuous
2. Punctuated Equilibrium- proposes that
species have long periods of stability
(several million years) interrupted by
geologically brief periods of significant
change during which a new species may
evolve
Gradualism
Time
vs.
Punctuated
Equilibrium
Time
Gradualism
vs.
Punctuated
Equilibrium
Possible Explanations of how
life arose.
Heterotroph Hypothesis
•Based on Scientific studies
Creation
•Based on religious belief
system
Millers experiment
• Stanley Miller, a graduate student in biochemistry, built
the apparatus shown here. He filled it with
• water (H2O), methane (CH4) , ammonia (NH3) and
• hydrogen (H2) but no oxygen
• He hypothesized that this mixture resembled the
atmosphere of the early earth. (Some are not so sure.) The
mixture was kept circulating by continuously boiling and
then condensing the water.
• The gases passed through a chamber containing two
electrodes with a spark passing between them
• . At the end of a week, Miller used paper chromatography
to show that the flask now contained several amino acids
as well as some other organic molecules
Millers
experiment
(IV) Heterotroph Hypothesis
• Is one proposed explanation for how
life arose and evolved on primitive
earth
• According to this hypothesis, the first
life forms were heterotrophic and had
to obtain their nutrients from the
environment
Primitive Earth
Wrong
Answer,
Human
(A) Primitive Earth
• Based on assumption
1. Earth was very hot consisting of inorganic
substances in all states: solid, liquid, and gas
2. Many energy sources including heat, lightning,
solar radiation(x-rays and U.V. rays), and
radiation from radioactive rocks
3. The atmosphere: water vapor, hydrogen,
methane gas, and ammonia
4. As the earth cooled, water condensed in the
atmosphere and rain fell forming seas described
as “hot, thin soup”
Primitive Earth (cont)
• Based on assumption
As the earth cooled, water condensed in the
atmosphere and rain fell forming seas described
as “hot, thin soup”
(B) Synthesis of Organic Compounds
1. In the seas, chemical bonds formed between
the dissolved substances
2. Eventually, various types of organic molecules
formed in the seas, including amino acids and
simple sugars
3. More complex organic compounds were then
formed by the interactions between the
simpler molecules
(C)
Nutrition
1. Some of the large. Complex molecules
formed groupings or clusters called
aggregates
2. These aggregates developed a surrounding
“membrane”
3. It is believed that aggregates absorbed
simple organic molecules from the
environment for food
4. Therefore, they carried on a form of
heterotrophic nutrition
(D)
Reproduction
1. In time, as these aggregates became more
complex and highly organized, they
developed the ability to reproduce
2. At the point where the ability to reproduce
had evolved, the aggregates were
considered to be living cells
(E) Heterotroph to Autotroph
1. It is thought that these early heterotrophic life
forms carried on a form of anaerobic
respiration known as fermentation
2. As a result of the extended periods of
fermentation, carbon dioxide was added to the
atmosphere
3. Eventually, as a result of evolution, some
heterotrophic forms developed the capacity to
use carbon dioxide from the atmosphere to
form organic compounds (food)
4. These organisms were the first autotrophs
(F) Anaerobes to Aerobes
1. Autotrophic activity (photosynthesis) added
free oxygen to the atmosphere
2. Over time, the capacity to use oxygen in
respiration (aerobic) evolved in both autotrophs
and heterotrophs
3. Present day organisms may be heterotrophic or
autotrophic; aerobic or anaerobic