Download HMS Beagle - Knappology

Evolution….
There is nothing constant in the
universe, all ebb and flow, and
every shape that is born bears in
its womb the seeds of change.
-Ovid
Genetic Diversity is…
Variety of genes in a population
Brought on by change, mutation or
evolution
Evolution is…
Change of an organism over time
Can be genetic, physical, metabolic,
etc.
How did the debate of
evolution begin?
HMS Beagle
Take a trip in 1831
Charles Darwin (pg 394)
Naturalist
Amazed by diversity
of life

What is diversity?
Studied anatomy
The World News in 1831
Earth’s
Earth’s
Populatio
Population
n
Exceeds
Its
Exceeds
Product
Product!
Could it be true?
Knew that species
reproduce more
offspring then
necessary. Why?
Not all survive.
Why?
A struggle exists.
What kind?
Which ones are
selected for
survival/reproductio
n?
Fitness
All organisms have
traits, traits that vary
throughout the
population.
Fitness is the ability
of an organism to
survive and
reproduce (pass
their genes on)
http://www.techapps.net/interactives/pepperMoths.swf
Selection
Artificial selection


Farmers use this
technique to breed
particularly desired
traits
If farmers select, why
can’t nature?
Natural selection


Survival of the fittest
Manner of change
that occurs when
organisms with
favorable traits for
their environment
survive and
reproduce
So who does nature
select for?
Organisms that have qualities that make
an organism successful or an organism
that has qualities that make an
organism unsuccessful?
Pg 395
HUGE DEAL!!!
Before Darwin, people believed that the
Earth and everything on it remained
unchanged.
Darwin was suggesting that new
species changed slowly over time from
pre-existing organisms.
English Peppered Moth
http://www.techapps.net/interactives/pepperMoths.swf
Scientist studied in
industrial areas

And rural areas
Usually white

rural
Black is favored

industrial
Why?
Fitness was the answer!
Black moths were more fit in industrial
areas
Pollution
 Coal burning (blackens trees)

White moths were favored in rural areas
Adaptation
Physical and behavioral traits that
enable an organism to survive and
reproduce
Types
Structural
Adaptations




Changes in “body”
parts
Tailbone
Thorns on a rose
Horse Hoof
Physiological
adaptations

Changes in
metabolism
Ancestors of the horse walked on spread-out
toes, a useful trait for walking on the soft,
moist grounds of primeval forests. As grasses
began to appear, diets shifted from foliage to
grasses, thus leading to larger and more
durable teeth. At the same time, horse's
needed to be capable of greater speeds in
order to outrun predators. This was attained
through the lengthening of limbs and the
lifting of some toes from the ground in such a
way that the weight of the body was gradually
placed on one of the longest toes, the third
(thus the lost of the minor digits)
Structural adaptations
Mimicry-organism copies appearance of
another species
Plant or Animal?
Mimicry
Monarch or Viceroy?
Owl moth
Structural Adaptation
Camouflage-organism blends in with the
surroundings
Camouflage
Camouflage
PS lab on page 398
Rate of Adaptation
Depends on the type of adaptation and
rate of reproduction
Physiological
adaptations
Changes in metabolism
EXN Science Wire...
Daily news from the
world of science.
Penicillin usually
kills all bacteria, but
now….
Fighting antibiotic-resistant bacterial
Pg 399
www.unitedstreaming.com
Bacteria Fight Back
 Bacterial resistance

http://www.pbs.org/wgbh/evolution/educ
ators/lessons/lesson6/act1notes.html
Resistant to Round-up?
Darwin’s Finches
Darwin Collected birds
He thought he had
various types
Closer inspection
suggested that they
were all finches

Skeletal and DNA
Each had own
adaptations

Why? (success)
What is a species?
A species is a group of organisms that
look alike and can interbreed (making
fertile offspring)
Speciation
Generation of a new species (occurs
only when interbreeding or the
production of fertile offspring are
prevented)
Pg 409
Physical barriers
Volcanoes split populations as lava
flows
Sea level changes can equal water level
barriers
Geographic isolation
Physical barrier separates a population
into groups
At first, organisms are the same
 Then organisms begin to change (adapt)
and their gene pool changes, therefore
creating a new species

Reproductive Isolation
Formerly interbreeding organisms are
prevented from producing fertile
offspring
DNA is so different that fertilization can’t
happen
Chromosome # differs
Behavioral

One group of frogs mates in fall, other in
summer
Order of events
Geographic isolation
Reproductive Isolation
Speciation
Visual of Speciation
The creation of a new
species challenges
scientists to ORGANIZE
Cladogram
Chart
Demonstrates how organisms relate to
one another over long/complex history
of change(s)
Reconstructs evolutionary change(s)
Cladogram
Evidence for Evolution
Fossils
Anatomical Studies
Functionless structures
Embryo development
DNA
(5) DNA
Same genes, different
function
100%
Chimps
90%
Sheep
71%
Snails
57%
Parsnip
(4) Embryo
development
Similarities in structure
In early development, we all have tails
and gill slits
Which is the human?
(3) Functionless
Structures
Vestigial structures
Example: wings of flightless birds, the
limb girdles of snakes, and the ear
muscles of humans
Why do vestigial structures continue to
be inherited?
Answer
Common ancestors did use them and
speciation hasn’t occurred far enough to
eliminate them completely
Vestigial or Not?
Appendix?
(located on the lower right hand side of the
abdomen)
 Was thought to function in filtering waste
and other materials
 Now…

Purpose of appendix
believed found
The function of the appendix seems related to
the massive amount of bacteria populating
the human digestive system. There are more
bacteria than human cells in the typical body.
Most are good and help digest food.
But sometimes the flora of bacteria in the
intestines die or are purged. Diseases such
as cholera or amoebic dysentery would clear
the gut of useful bacteria. The appendix's job
is to reboot the digestive system in that case.
Whale
(2) Anatomical Studies
(pg 401)
Do these forelimbs look similar?
Homologous structure
Skeleton is the same in structure but
NOT in function (homologous structure)
Example: Bone structure of a bird wing
and a human arm
Bird Wing and Human
arm (pg 401)
Anatomical Studies
Suggests common ancestor with same
basic structure
Over time, ancestor moved into different
environments so structures were used
for different functions because of
different needs for survival
Analogous Structure
If structures are similar in function, but
NOT in structure (analogous structure)
Do not suggest a common ancestor
Examples: Bird wings and butterfly
wings
Analogous Structures
http://www.fieldmuseum
.org/evolvingplanet/prec
ambrian_14.asp
Is there proof?
As the physical processes of Earth
changed, rock was constantly formed
and destroyed

Oldest rocks are 3.9 billion years old
Fossils
(1) Fossils
Evidence of an
organism that lived
long ago
Paleontologists
Study fossils to tell a story (CSI)
Fossil teeth can indicate the size of an
animal, how they moved, and what they
ate
 Fossils like Figure 14.1 (pg 371) could
suggest ideas on climate


PS lab pg 372
How do fossils form?
Figure 14.3 on page 373
http://www.fieldmuseum.org/evolvingpla
net/cambrian_14.asp
Dating a fossil ()
Figure 14.2 on page 372

Relative dating

Radiometric dating

Radioactive isotopes in rocks

Unstable Atoms that break down in predictable ways.
Based on these, an age can be obtained for a fossil
 Similar to what you see in CSI when an autopsy
is done and age is determined by presence of
wisdom teeth, growth plates, etc.
Geographic timeline
Timeline of Earth’s history
Divisions are based on organisms that
lived during that time
 Mass extinctions lead to a new division or
era


A period of time where a large group of
organisms DISAPPEARS from the fossil record
Eras
Precambrian



Cyanobacteria
Prokaryotes only at
first
At the end of the era,
the first eukaryotes
appear AND
multicellular
eukaryotes like
sponges and jellyfish
Paleozoic




Worms, sea stars,
arthropods (oceans)
Fish appear
Early seed plants
Amphibians and
reptiles
Eras
Mesozoic

Mammals appear





Cenozoic (Your Era)

Small and mouse-like
Dinosaurs
Birds at the end of
this era
Flowering plants
Continental drift


Mammals began to
flourish
Primates appear
Humans
(1) Fossils
Fossil record is full of skeletal remains
that seem to be changing
Camel
Whale (land dwelling, dog-like)
How? (page 402)
 http://www.pbs.org/wgbh/evolution/educato
rs/teachstuds/unit3.html

Fossil record suggests a
geological timeline
4.5 Billion years ago….
What happened?

Suggested that the Earth formed
Primitive Earth did not
have…
It did not have
oxygen
It did not have an
ozone
It did not have any
life
What changed?
Earth was very hot
Volcanoes spewed lava
and gas (relieving some
of Earth’s core
pressure)
Gases help create
original atmosphere
Next…
Earth began to cool
and water vapor
condensed = rain
Lightning brought
nitrogen to the “soil”
Series of suggested
events
Atmosphere changes
Organic molecules form
Molecules organized into proteins,
carbs, lipids and NAs
Cells appear (protocells, then
prokaryotes, then eukaryotes)


Protocell-Chains of AA linked
together=membrane; able to complete some
basic functions (make ATP, PS without
ribosomes)
Endosymbiont theory
Endosymbiont Theory
First eukaryotes came from
prokaryotes? How?
Page 385 (figure 14.15)
Symbiotic Relationship

Choroplasts and mitochondria have:
Their own DNA
 Ribosomes
 Ability to reproduce on their own

Biogenesis: Life comes
from life
However, how did life begin on Earth?
So far, no one has yet to scientifically
prove how life on Earth began.
 Several theories exist

The fossil record
suggests that the
earliest organisms
were…
Prokaryotes
What are those?
 They appeared 3.5-4 billion years ago
 For food, they used organic molecules



What are organic molecules?
Eventually, the food will run out! So…
Evolution generates…
Organisms that can make their own
food
First form of competition (between
producers and consumers)
The Earth Changes…
As photosynthetic bacteria increase, so
does the amount of OXYGEN
With OXYGEN comes the OZONE
OZONE blocks UV and increases the
amount of LIFE that can survive on
EARTH (more evolution)
Next to appear were…
Eukaryote organisms

1-2 billion years ago
Sequence of life was…
Bacteria
Protist
Fungi
Plants and Animals (seem to overlap)
Sequence of animal life
was…
Fish
Amphibians
Reptiles
Mammals
What about us?
Have we evolved?
How fast do new
species form?
Gradualism
(Darwin believed in this)
Idea that species originate through
gradual buildup of new adaptations
Camels
 Horses

Another idea was
Punctuated equilibrium
The idea that speciation occurs in
bursts (rapid) with long periods of
stability in between

Elephant
Mechanisms of
Evolution
Populations evolve;individuals don’t
Changes in genetic equilibrium equal
evolution
Natural Selection
Populations evolve;
individuals do not
Gene pool-entire collection of genes in
a population
Allele frequency-percent of a particular
allele in a population
Genetic equilibrium-allele frequency
doesn’t change from generation to
generation (so no evolution)
Changes in genetic
equilibrium equal
evolution
Mutation-change in the gene pool (DNA
change)

Most are harmful and selected against in a
population = no change, but sometimes a
mutation is selected FOR and = a change
Genetic Drift-change in allele frequency
by chance in a species (small
populations are more impacted)
How can you change
genetic equilibrium?
Cause the allele frequency to change
How do you change an
allele frequency?
Move organisms in and out of a
population (gain or lose genes)
“Altering the gene pool”
(Discussion)
What Darwin couldn’t
explain
Darwin knew that changes occurred in a
population (evolution), but he couldn’t
prove HOW they were happening
genetically.
What scientist genetically proved
Darwin’s theory of evolution with the
discovery of genes and alleles?
Gregor Mendel
Natural Selection
(acts on a population)
Selects which organisms pass their
genes on so allele frequency changes
from one generation to another
Types of Natural
Selection (pg 408)
Stabalizing selection
Directional selection
Disruptive selection
Stabalizing selection
Selection favors “average” individuals
resulting in a decrease of variation in a
population
Example: Human babies
Stabalizing Selection
Directional selection
Selection favoring individuals with
extreme forms of a trait
Can equal rapid evolution of a
population
Example: Finches and their bird beak
Directional Selection
Disruptive selection
Selection favors individuals at both ends
of extreme forms of a trait
Eliminate the intermediate
Can equal evolution of TWO new
species
Example: Insects that mimic vs. a
random insect
Disruptive Selection
Patterns of Evolution
Adaptive Radiation
Divergent Evolution
Convergent evolution
Adaptive radiation (pg
412)
Process of evolution of an ancestral
species into an array of species that
occupy different niches
(Newly evolved species evolve into
different species very fast)
Hawaiian Creepers
What could cause
adaptive radiation?
Geographic isolation
Happens on Islands a lot
Form of Divergent evolution
Divergent Evolution
Pattern of evolution in which species
that once were all similar to the
ancestor become more and more
distinct
(same become different)
(become less and less alike due to
changes base on environmental needsn.s.)
Adaptive radiation is
A form of divergent evolution
Example of Divergent
Evolution
Darwin’s Finches
Hawaiian Creepers
Convergent Evolution
(pg 413)
Pattern of evolution in which distantly
related organisms evolve similar traits
Different become similar
Happens when unrelated organism
occupy similar environments and face
similar selection pressures
Convergent Examples
Dolphins and fish
Swim in a streamlined environment
Convergent Examples
Birds, bats and
insects
Fly
Convergent Examples
Woodpeckers and
opossums
How they obtain
food
Critical Thinking
Hummingbird moths are night-flying
insects whose behavior and
appearance are similar to those of
hummingbirds. Explain how these two
organisms demonstrate convergent
evolution.
Skill Review
Biologists discovered two squirrel
species living on opposite sides of the
Grand Canyon. They hypothesize that
the species evolved from a common
ancestor. What observations or
experiments could provide evidence for
this hypothesis?
What geographic isolation event could
have started it all?
Another theory
associated with
evolution is how/where
did life come from.
Origin of life
Spontaneous Generation

Idea that nonliving materials could produce
life
Observation: Every year in the spring, the Nile River
flooded areas of Egypt along the river, leaving behind
nutrient-rich mud that enabled the people to grow that
year’s crop of food. However, along with the muddy
soil, large numbers of frogs appeared that weren’t
around in drier times.

Conclusion: It was perfectly obvious to people back then
that muddy soil gave rise to the frogs.
Observation: In many parts of Europe, medieval
farmers stored grain in barns with thatched roofs (like
Shakespeare’s house). As a roof aged, it was not
uncommon for it to start leaking. This could lead to
spoiled or moldy grain, and of course there were lots
of mice around.

Conclusion: It was obvious to them that the mice came
from the moldy grain.
Disproving the theory
Redi’s experiments

Pg 380 Figure 14.10
Pasteur’s experiments

Pg 381 Figure 14.11