Evolution1

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Evolution

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  should only be used for educational purposes
  (Fair Use Policy)

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Why are there so many different kinds of species?
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Lemurs of Madagascar
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Amazonian Frogs
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Did Humans Evolve from
Our ancestor was . . . ?!?!
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What is evolution?
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Notes

• Evolution genetic changes in a population of
  organisms over time
• Does not happen to individual organisms

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A brief history of evolution

• Charles Darwin

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How Do We Know that Evolution Has Occurred?
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Imprint Fossils
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Fossil Bones

• Bones and teeth of vertebrates are resistant
  enough to remain intact when the rest of the body
  has decayed.
• Dinosaur skeletons are among the most spectacular
  fossils ever found.

Sue, the largest, most complete T. rex fossil
ever found. It resides at the Field Museum in
Chicago.
A 12,000 year old mammoth skeleton
Back
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Formation of a Fossil
Water carries small rock particles to lakes and
seas.
Dead organisms are buried by layers of sediment,
which forms new rock.
The preserved remains may later be discovered and
studied.
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Insects in Amber
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Frozen Organisms
Right - Otzi, the famous Ice Man found frozen
in the Italian Alps
Left - Dima, a baby mammoth found preserved in
the Siberian permafrost by Russian miners.
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Tollund Man
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What Can You Learn From Fossils?
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What Can You Learn From Fossils?
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What Can You Learn From Fossils?
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What Can You Learn From Fossils?
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What Can You Learn From Fossils?
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What Can You Learn From Fossils?
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Trace fossils include burrows, tracks, even
fossilized poop!
Dinosaur tracks
Dinosaur Fish Poop
Fossil burrows
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Petrified Wood

• When wood is buried in ash or sandy sediments,
  silica can form within the wood structure,
  eventually replacing the organic material.

These petrified logs are found at Petrified
Forest National Park in Arizona.
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Footprints

• Dinosaur tracks are common occurrences in the
  southern and eastern U.S.
• Here is a section of tracks that were recently
  uncovered. Can you answer the following
  questions?

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Observation and Inference

• What is the size and nature of the organisms?
• Were the tracks made at the same time?
• How many animals were involved?
• Can you reconstruct the events that occurred?

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Observation and Inference

• In what direction did the animals move?
• Did they change speed or direction?
• Was the soil moist or dry?
• In what type of rock were the prints made?

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Observation and Inference

• The following summer some more digging revealed
  more of the track.
• What additional information have you gained that
  allows you to refine your answers?

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Observation and Inference

• Were the tracks made at the same time?
• How many animals were involved?
• Can you reconstruct the events that occurred?
• In what direction did the animals move?
• Did they change speed or direction?

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• In the final summer of the excavation one last
  part of the footprint trail was uncovered. Does
  this section provide additional information to
  refine your hypothesis?

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• So what happened?
• What part of your hypothesis is observation? What
  part is inference? What part is conjecture?

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Embryological Evidence
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Embryological Evidence
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Anatomical Evidence

• Homologous structures

Turtle
Alligator
Bird
Mammal
Ancient lobe-finned fish
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Anatomical Evidence
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Anatomical Evidence

• Vestigial Structures
• Ostrich wings
• Hind limbs on swimmers

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Snake Leg Spurs
Leg spurs are visible on the underside of this
female ball python.
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Reduced Eyes in Cave Dwellers
The fish Astyanax comes in two varieties the
surface-dwelling varitey is on the left, the
eyeless cave fish is on the right. The mutation
that eliminates eyes also gives the fish a larger
jaw and more taste buds.
Several examples of eyeless cave-dwelling animals
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Biochemical Evidence
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Biochemical Evidence
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Notes

• Evidence of evolution
• Fossils
• Embryological
• Anatomical
• Homologous (similar) structures, ex. Forelimbs of
  mammals have similar bone structure
• Vestigial (remnant, remaining, left over)
  structures, ex. Ostrich wings not used for flying
• Biochemical (molecular)
• DNA
• Amino acids

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Tiktaalik

• Evolution of four legs

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Evidence of Whale Evolution
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Evidence of Whale Evolution
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Evolution of Man
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Evidence of Human Evolution
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What Causes Evolution?
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Notes

• Adaptation A trait that allows an organism to be
  better suited to their environment.
• Behavior
• Anatomical (physical) feature

Feathers to attract females
Care for young
Producing thousands of eggs
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Observe

• What adaptations enable this organism to survive
  in its environment? How?
• Polar Bear

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Observe

• What adaptations enable this organism to survive
  in its environment? How?
• Armadillo

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Observe

• What adaptations enable this organism to survive
  in its environment? How?
• Star-nosed Mole

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Notes

• Source of adaptations (traits) are genes

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Notes

• Genetic variation genetic differences between
  organisms within the same population

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Notes

• Source of Genetic variation
• Mutations
• Must occur in the gametes to be passed on
• Sexual reproduction
• Independent assortment, crossing-over, and
  segregation creates different combinations of
  chromosomes in offspring

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Notes

• Mutations are changes in DNA.

Deletion
Substitution
Insertion
Frameshift Mutation causes the most changes
Point Mutation
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Notes

• Mutations
• can form new alleles
• can only be passed onto offspring if in
  reproductive cells (in gametes, not somatic
  body cells)

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Notes

• Crossing over when non-sister chromatids
  exchange genetic segments during meiosis

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Notes

• Segregation when homologous chromosomes
  separate during meiosis
• Independent assortment process by which genes
  segregate into different combinations

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Notes

• Mutation change in DNA
• Random
• DNA fails to copy correctly
• Mutagens anything that changes DNA
• Chemicals
• Radiation
• Not all matter to evolution
• No change to phenotype
• Small change (ears curl)
• Big change (genetic disease)
• can be beneficial, harmful, or has no effect at
  all depending on the environment.

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Notes

• Mutations and new combinations of genes create
  genetic variation
• More genetic variation -gt more phenotypic
  variation -gt evolution

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Why Sex?
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Notes

• Asexual Reproduction reproduction where the
  offspring has only one parent.
• Offspring is genetically identical to parent
• Low genetic variation
• Slower rate of evolution in species

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Notes

• Sexual reproduction reproduction where gametes
  from 2 parents form new offspring
• High genetic variation
• Higher rate of evolution in species

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• What are the similarities and differences between
  these two organisms?
• Are these the same species or different species?

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Moths!

• Both have the Scientific Name
• Biston betularia
• Both are the same moth, commonly called peppered
  moths, but with two different color variations.

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• During the early 1800s in Birmingham, England,
  birch trees had peppered trunks.
• 80 of the moth population was peppered
• 20 of the population was black
• Which had the better adaptation? Why?

What do you see?
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Notes

• Alleles
• N peppered color
• n black color
• 1800s 80 20

NN or Nn
(pepper)
nn
(black)
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Industrial Revolution occurred

• Factories created -gt more pollution

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Notes

• Alleles
• N peppered color
• n black color
• 1800s 80 20
• After the industrial revolution
• 1850s 20 80

NN or Nn
(pepper)
nn
(black)
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• In 1850
• 80 of the moth population was black
• 20 of the population was peppered
• What happened?

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• What do factories produce?
• Where does this stuff land?
• Peppered tree trunks were blackened by heavy
  pollution from factories.
• Which moth is better adapted to its environment?
  Why?

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Notes

• Gene pool all the alleles in a population
• Allele frequencies measure genetic variation.
• can be calculated for each allele in gene pool
• When the allele frequencies change, evolution has
  occurred

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How Does Evolution Occur?
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Notes

• Selection process where the most fit (adapted to
  environment) organisms survive and reproduce,
  passing their traits to their offspring.

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Notes

• Conditions for Selection
• Variation - different genes in Gene Pool and
  different phenotypes
• Adaptation organisms are selected to survive
  by Environmental pressures (predator, resources,
  climate, etc.) because of certain traits
• Overproduction some offspring survive to pass
  on selected trait
• Descent with modification the selected trait
  becomes more common in the population

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Notes

• Types of Selection
• Natural Selection
• Artificial Selection
• Sexual Selection

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Notes

• Fitness how well an organism is at leaving
  surviving offspring that can reproduce for the
  next generation
• depends on its environment

• Selection acts on the phenotype rather than the
  genotype of an organism
• Environmental pressures (predators, resources,
  climate, etc.) choose the best or most fit
  adaptation

Which has higher fitness in brown environments?
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How Does Natural Selection Work?
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Notes

• Natural selection process where certain forces
  of nature (predator, resources, climate, etc.)
  select which organisms survive to reproduce.

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How did giraffes get their long necks?

1. Creationism (God created them that way)
2. Stretch (Lamarck) use and disuse
3. Natural Selection (Darwin)

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Notes
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2
3

• Darwins Theory of Natural Selection
• Early giraffes had necks of various lengths
• Natural selection due to competition for food on
  trees lead to survival of the longer-necked
  giraffes
• Long-necked giraffes survive and reproduce this
  trait becomes more common in the following
  generations

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Natural Selection at Work

• Orchids fool wasps into "mating" with them.
• Non-poisonous king snakes mimic poisonous coral
  snakes.

• Katydids have camouflage to look like leaves.
• The male blue-footed booby exaggerates his foot
  movements to attract a mate.

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Camouflage and Coloration
This giraffe and grasshopper are not closely
related animals, but the same selective pressure
to blend in has led to similar color and markings.
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The monarch butterfly on the left is poisonous
and will make a bird that eats it sick. The
viceroy on the right is harmless, but the birds
that have made the mistake of eating a monarch
wont touch it.
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The yellow jacket on the right can afford to be
aggressive because it has a stinger to back up
its behavior. The hoverfly on the left is very
tame. It flies from flower to flower eating
nectar, confident that its colors will protect it
from any nosy predators.
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Mimicry (mimic environment)
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Mimicry (mimic other animal)
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Darwins Finches
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Toucan

• The toucan's beak is adapted to grab and crush
  fruit and nuts.
• It is strong like a nutcracker.

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Hummingbird

• A hummingbirds long thin beak can get to the
  nectar in flowers.

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Pelican

• The pelicans beak is adapted to scoop up fish to
  eat.

(Only in cartoons do they use their beaks to
transport fish to safety!)
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Woodpecker

• The woodpeckers chisel-like beak allows it to
  drill holes in trees and eat the insects within.

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Summary of Natural Selection
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What is Artificial Selection?How Does It Work?
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Notes

• Artificial Selection people (instead of nature)
  select which organisms get to reproduce

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Artificial Selection

• Selective breeding of dogs
• The ancestral dog (the gray wolf, Canis lupus)
• Modern dog breeds

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What do you think this dog was bred for? How can
you tell?

• Greyhound
• Egypt

• Since the Egyptian Fourth Dynasty (circa
  2575-2467 B.C.) and likely before, the greyhound
  has been known as a graceful and speedy animal,
  perhaps the fastest dog on Earth.

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What do you think this dog was bred for? How can
you tell?

• Alaskan Malamute
• Alaska

• This is the Alaskan malamute, an arctic sled dog
  named after the Mahlemut tribe of the breed's
  native Kotzebue Sound in northwestern Alaska.
  Bone and ivory carvings dated to 20,000 years ago
  show ancient malamutes almost identical to
  today's breed.

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What do you think this dog was bred for? How can
you tell?

• Chihuahua
• Mexico

• The Chihuahua, the smallest dog in the world, is
  named after the Mexican state of Chihuahua, where
  its type probably originated at least 9,000 years
  ago.

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Artificial Selection

• Selective breeding of pigeons

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Whats Sexual Selection?How Does It Work?
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Notes

• Sexual Selection process where mates choose with
  whom to reproduce based on certain traits.
• could produce features that are elaborate (ie.
  colorful feathers) but doesnt necessarily help
  against predators
• Male competition
• Female choice

Male elephant seals fight over territory
and females
Redback male gets bitten by female to mate
successfully
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Sexual Selection
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How are lethal alleles kept in the gene pool?
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Sickle Cell

• Red blood cells become sickle shaped and block
  blood vessels which cause pain, serious
  infections, and organ damage.
• Sickle cell is codominant
• H normal red blood cells
• S sickle blood cells
• HH normal
• SS all blood cells sickled
• HS half blood cells normal, half are sickled

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Malaria/Plasmodium

• Transmitted by Anopheles mosquito
• Plasmodium multiplies within red blood cells,
  causing fever, chills, nausea, flu-like illness,
  coma and death

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Sickle Cell and Malaria

• Sickled blood cells resistant to malaria
• Allele stays in population because heterozygous
  individuals have a higher fitness

Areas with sickle cell trait
Areas with malaria
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Huntington's Disease

• Huntingtons Disease degenerates brain cells
• Caused by a dominant allele
• Allele stays in population because symptoms dont
  show up until after people reproduced

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Notes

• Alleles in the gene pool
• New random mutations are constantly being
  generated in the gene pool
• Some of these alleles are lethal in a homozygous
  individual
• Example, the genotype aa is an individual with
  Tay Sachs disease
• However, the lethal allele may persist in the
  population if carried in a heterozygote
• Example, Aa is an individual who carries the
  allele for Tay Sachs, passes it onto the next
  generation, but does not show the disease

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Genetic Drift
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Notes

• Genetic drift chance events changes the
  frequency of genes in a population
• more common in small populations.
• causes a loss of genetic diversity.
• less likely to have some individuals that can
  adapt
• harmful alleles can become more common due to
  chance
• 2 Kinds
• Bottleneck
• Founder effect

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Notes

• Bottleneck effect genetic drift that occurs when
  an event drastically reduces population size.
• Natural disasters
• fire, flood, asteroid,
• volcano, tsunami,
• earthquake, hurricane
• Overhunting by humans

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Bottlenecks Reduce Variation
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Notes

• Founder effect genetic drift that occurs when a
  few individuals start a new population.
• Migration

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The Amish

• Ellisvan Creveld syndrome

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What Causes New Species to Arise?
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Notes

• Species organisms that interbreed under natural
  conditions producing viable offspring
• Are horses and donkeys the same or different
  species?

Horse
Mule (not viable, cannot reproduce)


Donkey
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Are these species?

• These spiders look different
• Can interbreed
• Yes
• Theridion grallator

• Bacteria reproducing asexually by dividing
• Yes, but asexual reproduction does not fit
  definition

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Are horses and donkeys one species?

• Donkeys and horses can interbreed to produce
  mules and hinnys
• Mules and hinnys are sterile
• No, because the offspring are not viable or
  fertile

Horse
Donkey
Mule
Hinny
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Notes

• Speciation the rise of a new species from one
  existing species.
• Caused by
• Reproductive isolation

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How do new species evolve?

• Fruit fly, Drosophila

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How do new species evolve?

• The scene
• Fruit flies eating bananas and laying eggs

• Disaster strikes
• Hurricane washes bananas and eggs on an island
  away from mainland

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How does isolation happen?

• Different fruits on island
• Selected to specialize in a different fruit
  preference

• Populations diverge
• Different environment and selective pressures on
  island. Anatomy and behavior change over time.
  Larger genetic differences build up.

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How do new species evolve?

• So we meet again
• Another storm takes island flies to mainland, but
  cant mate with mainland flies

• Island flies will not mate with mainland flies
  because they hang out on different fruit

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Notes

• Causes of speciation
• Low or no gene flow
• Gene flow movement of genes from one population
  to another (interbreeding)
• increases genetic variation
• The less gene flow, the more speciation.
• Isolated populations adapt to their own
  environments.
• Genetic differences adds up over generations.
• Reproductive Isolation members of different
  populations cannot mate successfully
• Types
• Geographic
• Behavioral
• Temporal

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New species form after a barrier prevents gene
flow
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Notes

• Geographic isolation
• physical barriers divide population
• land
• water
• mountains
• cliffs
• climate

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In the Beginning . . .

• Universe began with the Big Bang
• Earth is approximately 4.6 billion years old

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In the Beginning . . .

• As Earth cooled . . .
• Life arose on earth spontaneously
• Earliest life were bacteria

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In the Beginning . . .

• Millions of species arose on earth over billions
  of years

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Pangea
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Pangea would break apart . . .
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. . . to form the continents we know today
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Geographic Distribution of Living Species
Beaver
Beaver Muskrat Beaver andMuskrat Coypu
Capybara Coypu andCapybara
NORTH AMERICA
Muskrat
Capybara
SOUTH AMERICA
Coypu
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Notes

• Behavioral isolation
• includes differences in courtship or mating
  behaviors between populations

Satin bowerbird builds a channel between upright
sticks and decorates with bright blue objects
MacGregors Bowerbird builds a tall tower of
sticks and decorates with bits of charcoal
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Notes

• Temporal isolation
• timing of reproductive periods prevents mating
  between populations
• Ex. Frogs that mate in the spring dont mate with
  frogs that mate in the fall

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Other Reproductive Isolations

• Anatomy
• Lack of "fit" between sexual organs
• Offspring inviability or sterility

Mules are generally infertile
These damselfly penises illustrate just how
complex insect genitalia may be.
Chihuahuas and Great Danes are nearly impossible
to mate due to genitalia incompatibility
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How does isolation happen?

• Geographic isolation can start a speciation event
  but genetic changes are necessary to complete
  the process.

• Different selection pressures on island made
  population diverge genetically

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How does isolation happen?

• Different fruits on island
• Selected to specialize in a different fruit
  preference

• Island flies will not mate with mainland flies
  because they hang out on different fruit
• Larger genetic differences build up

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Evidence of Speciation
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Practice

1. A farmer wants to breed a much juicier orange, so
   he cultivates the seeds from the best oranges
   with that trait and crossbreeds the resulting
   trees. Is this an example of natural selection,
   sexual selection, artificial selection, or
   genetic drift? Explain.

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Practice

1. Suppose there is a population of lemmings
   inhabiting a prairie in the Great Plains. Heavy
   rains flood the area, leaving a few lemmings left
   alive. Is this an example of natural selection,
   sexual selection, artificial selection, or
   genetic drift? Explain.

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Practice

• Suppose that dolphins were hunting tuna in the
  Pacific Ocean. Tuna that can outswim the
  dolphins survive. Is this an example of natural
  selection, sexual selection, artificial
  selection, or genetic drift? Explain.

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Practice

1. An asteroid falls from space and creates a
   massive explosion in the Yucatan Peninsula. Most
   of the dinosaurs living in the area die from the
   impact. Is this an example of natural selection,
   sexual selection, artificial selection, or
   genetic drift? Explain.

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Practice

1. The male gray dove makes a cooing sound when
   attracting a mate. Is this an example of natural
   selection, sexual selection, artificial
   selection, or genetic drift? Explain.

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Practice

• Among kangaroo mice, even though there are
  variations in coat color, the mottled tan coat
  color seems to be the color of the majority of
  the mice. This may camouflage them from
  predators. Is this an example of natural
  selection, sexual selection, artificial
  selection, or genetic drift? Explain.

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Practice

1. Among the elephant seals, only the toughest male
   gets to breed with a harem of females. Is this an
   example of natural selection, sexual selection,
   artificial selection, or genetic drift? Explain.

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Practice

1. Suppose a guava fruit that contained fruit fly
   eggs was blown onto an island that didnt have
   other fruit fly populations. The eggs hatch, and
   the resulting flies populate the island. Is this
   an example of natural selection, sexual
   selection, artificial selection, or genetic
   drift? Explain.

150
Practice

1. Scientists want to see if they can breed hairless
   rabbits. So they take the ones with the least
   amount of fur to interbreed together over a span
   of many generations. Is this an example of
   natural selection, sexual selection, artificial
   selection, or genetic drift? Explain.

151
Practice

1. A farmer wants to breed a much juicier orange, so
   he cultivates the seeds from the best oranges
   with that trait and crossbreeds the resulting
   trees. Is this an example of natural selection,
   sexual selection, artificial selection, or
   genetic drift? Explain.

152
Practice

1. Suppose there is a population of lemmings
   inhabiting a prairie in the Great Plains. Heavy
   rains flood the area, leaving a few lemmings left
   alive. Is this an example of natural selection,
   sexual selection, artificial selection, or
   genetic drift? Explain.

153
Practice

1. An asteroid falls from space and creates a
   massive explosion in the Yucatan Peninsula. Most
   of the dinosaurs living in the area die from the
   impact. Is this an example of natural selection,
   sexual selection, artificial selection, or
   genetic drift? Explain.

154
Practice

• Suppose that dolphins were hunting tuna in the
  Pacific Ocean. Tuna that can outswim the
  dolphins survive. Is this an example of natural
  selection, sexual selection, artificial
  selection, or genetic drift? Explain.

155
Practice

1. The male gray dove makes a cooing sound when
   attracting a mate. Is this an example of natural
   selection, sexual selection, artificial
   selection, or genetic drift? Explain.

156
Practice

• Among kangaroo mice, even though there are
  variations in coat color, the mottled tan coat
  color seems to be the color of the majority of
  the mice. This may camouflage them from
  predators. Is this an example of natural
  selection, sexual selection, artificial
  selection, or genetic drift? Explain.

157
Practice

• Among snowshoe hares, some are born with thicker
  fur than others, which allows them to survive
  harsh winters. Is this an example of natural
  selection, sexual selection, artificial
  selection, or genetic drift? Explain.

158
Practice

1. Among the elephant seals, only the toughest male
   gets to breed with a harem of females. Is this an
   example of natural selection, sexual selection,
   artificial selection, or genetic drift? Explain.

159
Practice

1. Suppose a guava fruit that contained fruit fly
   eggs was blown onto an island that didnt have
   other fruit fly populations. The eggs hatch, and
   the resulting flies populate the island. Is this
   an example of natural selection, sexual
   selection, artificial selection, or genetic
   drift? Explain.

160
Practice

• Among one species of the Galapagos finches, some
  birds have longer, more slender beaks than
  others, and therefore have an advantage in
  catching more insects. Is this an example of
  natural selection, sexual selection, artificial
  selection, or genetic drift? Explain.

161
Practice

1. Scientists want to see if they can breed hairless
   rabbits. So they take the ones with the least
   amount of fur to interbreed together over a span
   of many generations. Is this an example of
   natural selection, sexual selection, artificial
   selection, or genetic drift? Explain.

162
How Do You Show Evolutionary Relationships
between Species?
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Notes

• Phylogenetic tree Diagram that shows ancestry
  among different species (like a family tree)

164
Phylogenetic Tree
165
Phylogenetic Tree for Mammals
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Phylogenetic Tree

• Shows the common ancestor

167
What are the Differences?

• Human DNA
• AGGCATAAACCAACCGATTA
• Chimpanzee DNA
• AGGCCCCTTCCAACCGATTA
• Gorilla DNA
• AGGCCCCTTCCAACCAGGCC
• Common ancestor DNA
• AGGCCGGCTCCAACCAGGCC

168
Which one is the correct tree?

• G gorilla
• C chimpanzee
• H human
• A common ancestor

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What Happens When Whole Species Die?
170
Notes

• Extinction When all organisms in a species die.

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Notes

• Genetic variation increases the likelihood that
  some members of a species will survive changes in
  the environment

172
Notes

• Biodiversity amount of different species living
  in a region
• A higher biodiversity increases the chances that
  some organisms survive major changes in the
  environment
• Which environment has the higher biodiversity?

Environment A 3 Oak Trees 4 Pigeons 5 Squirrels
Environment B 35 Gophers
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Notes

• Biodiversity amount of different species living
  in a region
• A higher biodiversity increases the chances that
  some organisms survive major changes in the
  environment
• Which environment is more stable?

Environment A 3 Oak Trees 4 Pigeons 5 Squirrels
Environment B 35 Gophers
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How do you read sedimentary layers?
175
How do you read sedimentary layers?
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Movement of Layers
Sea level
Sea level
Sedimentary rocks form in horizontal layers.
When part of Earths crust is compressed, a bend
in a rock forms, tilting the rock layers.
As the surface erodes due to water, wind, waves,
or glaciers, the older rock surface is exposed.
New sediment is then deposited above the exposed
older rock surface.
179
Practice

• Which layer is the oldest and youngest? How do
  you know?

180
Practice

• Which layer(s) shows biodiversity? How?

181
Practice

• Which layer(s) shows evidence of mass extinction?
  How?

182
Practice

• Which layer(s) show new species arising? Whats
  the evidence?