Transcript Evidence for Evolution

RTW Friday, January
st
31
What is your definition for evolution?
Today’s Agenda
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Recommendations for 2014-15
 Anatomy/Physiology
 Anatomy/Physiology
 Biology
Honors
II
 Environmental Science
 Marine Science
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Test corrections
Start vocabulary
Evolution Vocabulary
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Endosymbiotic Theory
Evolution
Convergent Evolution
Coevolution
Punctuated Equilibrium
Descendant
Ancestor
Fossil
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Homogolous Sturcture
Vestigial Structure
Analogous Structure
Embryology
Biogeography
Hominid
Candidate Fossils
RTW Monday, February
rd
3
What came first, the chicken or the egg?
ORIGINS OF LIFE
Theories of the Origin of Life
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Abiogenesis
 Primordial
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soup
Endosymbiotic theory
Hydrothermal vents
Panspermia
Abiogenesis
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= "non biological origins“: hypothetical
generation of life from non-living matter.
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Spontaneous generation
Primordial Soup
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Famous Miller-Urey experiment (1953) suggested
that lightning might have helped create the key
building blocks of life on Earth in its early days.
 Over
millions of years, larger and more complex
molecules could form.
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Electric sparks can generate amino acids and sugars
from an atmosphere loaded with water, methane,
ammonia and hydrogen.
Endosymbiosis
Deep-Sea Vents
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The deep-sea vent theory
suggests that life may have
begun at submarine
hydrothermal vents
These vents spew key hydrogenrich molecules. Their rocky nooks
could then have concentrated
these molecules together and
provided mineral catalysts for
critical reactions.
Even now, these vents, rich in
chemical and thermal energy,
sustain vibrant ecosystems.
Panspermia
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= life did not begin on Earth at all, but
was brought here from elsewhere in
space
Rocks regularly get blasted off Mars by
cosmic impacts, and a number of
Martian meteorites have been found on
Earth that some researchers have
controversially suggested brought
microbes over here, potentially making
us all Martians originally.
“Happy Birthday Earth!”
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How old are you?
 The
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Earth is 4.6 BILLION years old!
In this activity…You will be designing a geological
birthday card for the Earth for a specific time
period.
To do this you will need to calculate your
“Geological Birthday”…
Calculating Your Geological Birthday
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1.) Divide the age of the Earth by the
number of days in a year.
2.) Next add the number of days from
the beginning of the year until your
birthday.
3.) Subtract this number of days from the
total number of days in a year.
4.) Figure out the equivalent number of
years on the geological time scale.
5.) Round to the nearest million years.
Month
# of
Days
January
31
February
28
March
31
April
30
May
31
June
30
July
31
August
31
September
30
October
31
November
30
December
31
Example Birthday: September
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th
5
1.) 4.6 billion/365 = 12,602,740 years per day
2.) 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 5 = 248
days
3.) 365 - 248 = 117 At the end of the year my birthday
was 117 days ago
4.) (12,602,740 years/day) x (117 days) =
1,474,520,580 years
5.) 1,474,520,580 rounds to 1,500,000,000 which can
also be expressed as 1,500 MYA or the Metoproterozoic
Now what?
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Design a birthday card for the Earth at that time
Your card should convey something about that time
period.
 Environment
 Presence
or absence of life
 Arrangement of continents
 Anything else you learned about that time
http://www.ucmp.berkeley.edu/help/timeform.php
RTW Tuesday, February
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th
4
What is one theory of the origins of life that we
discussed yesterday and what does it entail?
Evidence for Evolution Project
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You will be placed into groups of 6
Each group will have specialists:
 Anatomist-
study the structure of organisms
 Physiologist- study the function of organisms
 Paleontologist- study fossils
 Molecular biologist- study genetics
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Within your group you need to have 2 of the same
specialists (one specialist will not be represented)
Evidence for Evolution Project
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With your role you will research 4-5 examples of
evidence for evolution
Find specific examples, so when you present to the
class you will have different examples to share (also
find the dates when the evidence was discovered)
To start your research: Google “Evidence for
evolution webquest”
 Scroll
down and utilize the links for your role
Evidence for Evolution Project
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As a group you are creating a poster that will be
presented (“Evidence for evolution webquest”)
Organize your information in a chart:
Evidence for Evolution
Special Areas of
Interest
Anatomy
Molecular Biology
Paleontology
Evidence
(descriptions or
drawings)
Significance
RTW Wednesday, February
th
5
What is one piece of evidence for evolution (think
about what you researched yesterday)?
RTW Thursday, February
th
6
How does this picture provide support for the theory
of evolution?
RTW Friday, February
th
7
What is a vestigial structure and what is an example
of one?
HAPPY FRIDAY!
Key Concept
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Evidence of common ancestry among
species comes from many sources.
Evidence for evolution came from
several sources.
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Fossils provide evidence of evolution.
 Fossils
in older layers are more primitive than
those in the upper layers.
Paleontology provides evidence to
support evolution.
The study of geography provides
evidence of evolution.
Island species most closely resemble nearest
mainland species
 Populations can show variation from one
island to another
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Embryology provides evidence of
evolution.
Identical larvae, different adult body forms
 Similar embryos, diverse organisms
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The study of anatomy provides
evidence of evolution.
Homologous structures are similar in
structure but different in function.
 Homologous structures are evidence of a
common ancestor.
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Human hand
Mole foot
Bat wing
The study of anatomy provides
evidence of evolution.
Analogous structures have a similar
function.
Human hand
Mole foot
 Analogous structures are NOT evidence of a
common ancestor.
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Fly wing
Bat wing
Structural patterns are clues to the
history of a species
• Vestigial structures are remnants of organs or structures
that had a function in an early ancestor.
• Ostrich wings are examples of vestigial structures.
Molecular & genetic evidence
support fossil & anatomical evidence
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Two closely-related organisms will have similar DNA
sequences.
Humans share a common ancestor
with other primates.
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Primates are mammals with flexible hands and feet,
forward-looking eyes and enlarged brains.
Anthropoids are humanlike primates.
So why are humans so advanced?
BRAINSTORM with a shoulder partner about what
makes us more advanced than other primates and
organisms
So why are humans so advanced?
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Bipedal means walking on two legs.
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foraging
carrying infants and food
using tools
HUGE brains!
 Language
 Use of tools
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Article Review
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Read the article.
Write down the answers in your notebook (part of
the notebook check).
When done, turn to your shoulder partner and
summarize your article.
RTW Monday, February
th
10
Based on embryology & developmental patterns, what can
you infer from this diagram?
A.
B.
C.
D.
They are offspring are from a
common parent
They have a distant common
ancestor
They developed in the same
location
They evolved into the same
species
NATURAL SELECTION
Or, how did we get here….
Natural Selection
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Natural selection is a mechanism by which
individuals that have inherited beneficial
adaptations produce more offspring on average
than do other individuals.
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Heritability is the ability of a trait to be passed down.
There is a struggle for survival due to overpopulation
and limited resources.
Darwin proposed that adaptations arose over many
generations.
Natural selection explains how
evolution can occur.
• There are four main principles to the theory of natural
selection.
– variation
– overproduction
– adaptation
– descent with modification
ADAPTATION
DESCENT
VARIATION
OVERPRODUCTION
with
MODIFICATION
Variation
1. Reproduction occurs with variation
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This variation is heritable (traits inherited from parents)
Variation
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Variation is a difference in a physical trait.
 Galápagos
tortoises that live in areas with tall plants
have long necks and legs.
 Galápagos finches that live in areas with hard-shelled
nuts have strong beaks.
Overproduction
2. Overproduction of offspring (too many babies!)
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There is competition among living things
More are born or hatched or whatever, than survive and
reproduce
Adaptations
3. An adaptation is a feature that allow
an organism to better survive in its
environment.
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Species are able to adapt to their
environment.
Adaptations can lead to genetic
change in a population.
Descent with Modification
4. Selection determines which individuals enter the
adult breeding population
 This
selection is done by the environment
 Those which are best suited reproduce
 They pass these well suited characteristics on to their
young
 Fitness
describes how reproductively successful an
organism is in its environment.
This lecture keeps evolving…..
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Survival of the Fittest means those who have the most
offspring that reproduce
‘Descent with modification from a common ancestor,
NOT random modification, but, modification shaped
by natural selection’
Natural selection acts on existing
variation.
• Natural selection can act only on traits that already exist.
• Structures take on new functions in addition to their
original function.
five digits
wrist bone
Other Evolutionary Theories
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Lamarckism
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Inheritance of acquired characteristics
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E.g., giraffes really wanted leaves, so they stretched their necks
and…..
‘Cave dwelling fish don’t use their eyes so they disappear’
‘We don’t use our appendix so it is disappearing’
RTW Tuesday, February
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th
11
Explain why some animals have more or fewer
offspring at a time. Which do you think is the better
strategy?
Mechanisms of Change
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Gene Flow
 Migration
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& Emigration
Genetic Drift
 Bottleneck
Effect
 Founder Effect
 Speciation
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Non-random mating
 Sexual
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Selection
Genetic Recombination
Gene flow is the movement of
alleles between populations.
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Gene flow
 occurs
when individuals join
new populations and
reproduce.
 keeps neighboring
populations similar.
 Low gene flow increases
the chance that two
populations will evolve into
different species.
bald eagle migration
Migration & Emigration
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Gene flow moves alleles from one population to
another.
Genetic drift is a change in allele
frequencies due to chance.
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Genetic drift causes a loss of genetic diversity.
It is most common in small populations.
A population bottleneck can lead to genetic drift.
 It
occurs when an event
drastically reduces
population size.
 The bottleneck effect is
genetic drift that occurs
after a bottleneck event.
Genetic Drift
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Genetic drift has negative effects on a population.
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less likely to have some individuals that can adapt
harmful alleles can become more common due to chance
Genetic drift changes allele frequencies due to chance alone.
Founder effect
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The founding of a small population can lead to
genetic drift.
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It occurs when a few individuals start a new population.
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The founder effect is genetic drift that occurs after start of
new population.
Sexual selection occurs when certain
traits increase mating success.
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Sexual selection occurs due to
higher cost of reproduction
for females.
 males
produce many sperm
continuously
 females are more limited in
potential offspring each cycle
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Sexual selection selects for traits that improve
mating success.
Types of Sexual Selection
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There are two types of sexual
selection.
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intrasexual selection:
competition among males
intersexual selection: males
display certain traits to females
Genetic Recombination
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Mutations produce the genetic variation needed for
evolution.
Exit Slip
There are many different species of birds, but they all
have different songs. Explain what kind of
mechanism of change this is and how it works.
Vocab
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Evolution
Natural selection
Variation
Fitness
Adaptation
Descendant
Vestigal structure
Homologous structure
Analogous structure
RTW Wednesday, February
th
12
Write down an example of an animal that
has adapted to survive in its
environment.
Ipad Activity
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Google “Natural Selection Examples” and click first
option (Discovery Channel)
Pick five examples
For each example, answer the following IN YOUR
NOTEBOOK:
1.
2.
3.
Name of species
Describe the trait being selected.
How does the trait help the organism survive in its
environment?
Peppered Moths
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An example of evolution of a species over the past
200 years
Before the Industrial Revolution in England the trees
were a mottled white color.
Coal burning factories began producing soot that
covered the forests, making the trees black in color.
The peppered moth population responded to this
change, by adapting to their environment
Moth Activity
Instructions
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You will be given a moth outline
Cut it out
Color it (AT LEAST 2 COLORS)
Camouflage the moth for a specific surface around
the room