Interest Grabber

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Interest Grabber
Section 15-1

• A Trip Around the World
• While on his voyage around the world aboard the
  H.M.S. Beagle, Charles Darwin spent about one
  month observing life on the Galápagos Islands.
  There, he encountered some unique animals, such
  as finches and tortoises.

1. On a sheet of paper, list five animals that
you have encountered in the past two days. 2.
How do these animals differ from the finches and
tortoises of the Galápagos Islands? (Examine
Figures 153 and 154 in yourtextbook.) 3.
Propose a hypothesis to account for the
differences between the animals that you observed
and the finches and tortoises of the Galápagos
Islands.
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Section Outline
Section 15-1

• 151 The Puzzle of Lifes Diversity
• A. Voyage of the Beagle
• B. Darwins Observations
• 1. Patterns of Diversity
• 2. Living Organisms and Fossils
• 3. The Galápagos Islands
• C. The Journey Home

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Figure 151 Darwins Voyage
Section 15-1
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Charles Darwin

• Born February 12th, 1809 in England
• Degree Cambridge University
• Severed as a Naturalist on the HMS Beagle, for a
  survey of the coasts of South America.
• During this time he had time to examine local
  biota (plant and animal life of a region). He
  made a large collection of specimens, but more
  importantly he asked questions.
• 1859 The Origin of Species is released.

http//www2.lucidcafe.com/lucidcafe/library/96feb/
darwin.html
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The Theory of Evolution

• This book proposed Darwins hypothesis that life
  changes over time.
• What evidence is there?
• Fossil Record (Fossils are preserved remains of
  ancient organisms)
• The fossils found in the most recent strata
  (layer) are often very similar to still living
  species or, in some cases indistinguishable
• The older the strata are in which a fossil is
  found the more different the fossil will be from
  living representatives.
• Darwin reasoned earlier plant/animal life evolved
  into their descendents in the more recent strata
  (time).

What Evolution Is Ernst Mayr
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Darwins Observations

• Diversity
• Biota (Plants and Animals) are well suited for
  the ecosystem.
• Animal populations are specific to their own
  location.
• No kangaroos in England, despite similar
  ecosystems.
• Land tortoises varied in physical properties from
  one island to another. (Galapagos Islands)
• Finches varied from one island to another. The
  shape of their beak was specific to their food
  supply. (Galapagos Islands)

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Giant Tortoises of the Galápagos Islands
Section 15-1
Pinta
Tower
Marchena
Pinta IslandIntermediate shell
James
Fernandina
Santa Cruz
Isabela
Santa Fe
Hood Island Saddle-backed shell
Hood
Floreana
Isabela Island Dome-shaped shell
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Interest Grabber
Section 15-2

• My, How Youve Changed!
• Prior to the 1800s, life scientists knew that
  living things changed over generations. They just
  didnt know how these changes were brought about.

1. Divide a sheet of paper into two columns and
title the first one Inherited Characteristics.
Title the second column Acquired Characteristics.
In the first column, list the characteristics
that you believe you have always had. For
example, you may have brown eyes or curly hair.
2. In the second column, list your acquired
characteristics. For example, you may have
learned how to play a musical instrument. 3.
Which of the items in your lists do you think
you might pass on to your children? Explain your
answer.
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Section Outline
Section 15-2

• 152 Ideas That Shaped Darwins Thinking
• A. An Ancient, Changing Earth
• 1. Hutton and Geological Change
• 2. Lyells Principles of Geology
• B. Lamarcks Evolution Hypotheses
• 1. Tendency Toward Perfection
• 2. Use and Disuse
• 3. Inheritance of Acquired Traits
• 4. Evaluating Lamarcks Hypotheses
• C. Population Growth

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Geology and Fossils

• Before 1831 there were two beliefs about the
  world
• The world is young and all living things were the
  same as they always have been. (A constant world
  of short duration)
• The world goes through different cycles, each
  ending with a catastrophic event. ( A world of
  infinite duration)
• Hutton
• - Geological changes take millions of years.
  Some rocks are moved up due to forces within,
  while other rocks are buried and others form new
  land masses such as the Galapagos Islands. These
  masses are then shaped by wind, rain, heat and
  cold temperature.

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Lyells Principles of Geology

• Charles Lyell
• Title Principles of Geology
• Thesis Scientists must explain past events in
  terms of processes that they can actually
  observe, since processes that shaped the Earth
  millions of years earlier continue in the
  present.
• Examples
• Volcanic eruptions forming new land masses.
• Earthquakes disrupting coast lines.
• Glaciers carving and creating water ways.
• Could life change as well?

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Movement of Earths Crust
Section 15-2
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.
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Figure 157 Lamarcks Theory of Evolution
Section 15-2
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Living Organisms Change

• Jean-Bastiste Lamarck (1809)
• Lamarck proposed that by selective use or disuse
  of organs, organisms acquired or lost certain
  traits during their lifetime. These traits could
  then be passed on to their offspring. Over time,
  this process led to change in a species.
• -Tendency for perfection
• Use and disuse (Use wings? Increase size
  Do not use wings? Decrease size)
• - Inheritance of acquired traits (Build muscle
  for your kids)
• Lamarcks hypothesis was wrong. Why?

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Population Growth

• Thomas Malthus published a book stating that more
  human offspring were being born than people were
  dying. If this continued, the human population
  would grow and sooner or later there would be
  insufficient living space and food for everyone.
• Factors against War, famine, and disease
• Darwin looked more at plants and other animals
  that produced large numbers of seeds or eggs.
  These organisms did not overpopulate the Earth.

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Interest Grabber
Section 15-3

• When Is a Flipper a Wing?
• All living things are related. Some relationships
  are easy to seeyour pet cat may not roar like a
  lion, but it clearly resembles one.Other
  relationships are less obvious.

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Interest Grabber continued
Section 15-3

• 1. On a sheet of paper, construct a table that
  has five columns and six rows. In the columns,
  write the following heads Animal Group, Example,
  Legs, Fins, and Tail. Then, place the following
  animal groups in their own row Mammal, Bird,
  Fish, Amphibian, Reptile, and Insect.
• 2. Give one example for each group, and then fill
  in the informationfor that example. For Legs,
  write in the number of legs that eachanimal has.
  Do animals with fins have legs? Do animals with
  wingshave legs? If so, how many?
• 3. Can you tell from your table if a fish is more
  closely related to a birdor to an amphibian?
  Explain your answer.

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Section Outline
Section 15-3

• 153 Darwin Presents His Case
• Publication of On the Origin of Species
• 1. Darwin and Wallace
• B. Inherited Variation and Artificial Selection
• C. Evolution by Natural Selection
• 1. The Struggle for Existence
• 2. Survival of the Fittest
• 3. Descent With Modification
• D. Evidence of Evolution
• 1. The Fossil Record
• 2. Geographic Distribution of Living Species
• 3. Homologous Body Structures
• 4. Similarities in Embryology
• E. Summary of Darwins Theory
• F. Evolutionary Theory Since Darwin

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Concept Map
Section 15-3
Evidence of Evolution
includes
which is composed of
which indicates
which implies
which implies
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Darwin and Wallace

• Darwin and Alfred Russel Wallace had similar
  theories about change in living organisms.
• Darwins book The Origin of the Species and
  Wallaces essay were presented together.
• Galapagos Island Finches
• 13 Species
• Theories of evolution
• -Modification by Natural Selection
• -Descent with modifications
• Common ancestry

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Natural Selection

• Natural Selection aka Survival of the fittest
• Individuals that are better suited to their
  environment survive and reproduce most
  successfully.
• Over time changes increase a species fitness in
  its environment.
• This takes time, genetic diversity and
  environment selective pressures.
• Fitness is an individual organisms ability to
  survive and reproduce in it specific environment.
• Darwin proposed fitness is the result of
  adaptations. Adaptations is an inherited trait
  that increases an organisms chance of survival.
• Struggle for existence
• Each organism must compete to obtain food, living
  space, and other necessities.

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Common Descent

• All species were derived from common ancestors.
  This is called common descent.
• Each living species has descended, with changes
  from other species over time. This principle is
  descent with modification.
• All living organism are related to one another
  and if you go back in time you will find common
  ancestors.

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Figure 1514 Geographic Distribution of Living
Species
Section 15-3
Beaver
Beaver Muskrat Beaver andMuskrat Coypu
Capybara Coypu andCapybara
NORTH AMERICA
Muskrat
Capybara
SOUTH AMERICA
Coypu
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Evolution in Process

• Evidence
• Homologous and analogous structures
• Homologous structures are characteristics in
  different species which were inherited from a
  common ancestor. (Forelimb structure)
• Analogous structures are characteristics in
  different species that perform the same or
  similar function but evolved through different
  pathways. (Bird and insect wings)

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Figure 1515 Homologous Body Structures
Section 15-3
Turtle
Alligator
Bird
Mammal
Ancient lobe-finned fish
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• Vestigial Structures are homologous structures
  that serve no important functions. (Human
  appendix)
• Embryology (Study of embryos)
• The embryonic stages of vertebrates (animals with
  a backbone) are very similar.

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Artificial Selection

• Artificial Selection is the selective breeding of
  specific organisms for a specific trait. (Goes
  against natural selection.)
• Example Breeds of dogs
• Agricultural products
• Beefalo (Cow and Buffalo)
• Mule (Donkey and Horse)

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Artificial Selection

• All breeds of dog are descended from canis lupus
  - the grey wolf

http//www.bbc.co.uk/schools/gcsebitesize/biology/
variationandinheritance/3evolutionrev9.shtml
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Internet
Go Online

• The latest discoveries in evolution
• Interactive test
• Articles on evolution
• For links on evolution, go to www.SciLinks.org
  and enter the Web Code as follows cbn-5151.
• For links on Darwin, go to www.SciLinks.org and
  enter the Web Code as follows cbn-5152.
• For links on natural selection, go to
  www.SciLinks.org and enter the Web Code as
  follows cbn-5153.

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Section 1 Answers
Interest Grabber Answers
1. On a sheet of paper, list five animals that
you have encountered in the past two
days. Sample answers dogs, cats, insects,
snakes, birds, and so on. 2. How do these
animals differ from the finches and tortoises of
the Galápagos Islands? (Examine Figures 153 and
154 in yourtextbook.) Students may not see a
noticeable difference between birds in their area
and finches. However, the land tortoises, which
are very large, would be very different from any
turtles that students may have on their lists. 3.
Propose a hypothesis to account for the
differences between the animals that you observed
and the finches and tortoises of the Galápagos
Islands. Sample hypothesis Animals become well
suited to their surroundings.
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Section 2 Answers
Interest Grabber Answers
1. Divide a sheet of paper into two columns and
title the first one Inherited Characteristics.
Title the second column Acquired Characteristics.
In the first column, list the characteristics
that you believe you have always had. For
example, you may have brown eyes or curly hair.
Students should list traits that are
genetically influenced. 2. In the second column,
list your acquired characteristics. For example,
you may have learned how to play a musical
instrument. Remind students that many features,
including skills, appearance, and athletic
ability, can be changed to some degree by
effort. 3. Which of the items in your lists do
you think you might pass on to your children?
Explain your answer. Genetically influenced
traits are passed on. Some items, such as musical
or athletic talent, may have both inherited and
learned components.
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Section 3 Answers
Interest Grabber Answers

• 1. On a sheet of paper, construct a table that
  has five columns and six rows. In the columns,
  write the following heads Animal Group, Example,
  Legs, Fins, and Tail. Then, place the following
  animal groups in their own row Mammal, Bird,
  Fish, Amphibian, Reptile, and Insect.
• 2. Give one example for each group, and then fill
  in the informationfor that example. For Legs,
  write in the number of legs that eachanimal has.
  Do animals with fins have legs? Do animals with
  wingshave legs? If so, how many?
• Fish do not have legs. Birds have two legs,
  while insects have six legs (three pairs).
• 3. Can you tell from your table if a fish is more
  closely related to a birdor to an amphibian?
  Explain your answer.
• It is difficult to tell from the table that a
  fish is more closely related to an amphibian than
  to a bird. Accept all reasonable explanations.
  Students may say that the fish is more closely
  related to the amphibian than to the bird because
  an amphibian and a fish spend time in the water.

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