Transcript Chapter 10 Principles of Evolution

Principles of
Evolution
Chapter 10
Early Ideas About Evolution
 Carolus
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Linnaeus
Botanist
Classification of
organisms
(Taxonomy)
Still used today
Developed the
species idea
• Species-organisms
so related that can
interbreed
Early Ideas About Evolution
 Georges
Louis
Leclerc de Buffon
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Proposed species
shared ancestors
Felt Earth was
older than 6000
years
Comparative
anatomy – similar
structures in
related species
Early Ideas About Evolution
 Erasmus
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Darwin
Darwin’s
grandfather
All living things
from a common
ancestor
Gave rise to his
grandson’s
theory
Early Ideas About Evolution
 Lamarck’s
Evolution
Hypotheses
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Living things have
changed over
time—and that all
species were
descended from
other species.
Organisms change
to adapt to their
environment
Early Ideas About Evolution

Tendency Toward
Perfection
• All organisms strive to
be complex and
perfect
• This leads to constant
change
• This change is a
response to the
environment and a
desire to be perfect
Early Ideas About Evolution
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Use and Disuse
• Organisms could
alter the size or
shape of an organ Use it or lose it
• If you don’t use the
structure it will go
away
• If you use it
continually, it will get
larger
Early Ideas About Evolution

Inheritance of
Acquired Traits
• Animals can
change their body
• If they do they
can pass on the
new trait
• Ex. – Giraffes
and long necks
Early Ideas About Evolution

Evaluating Lamarck’s Hypotheses
• Many of Lamarck’s ideas were incorrect
Early Ideas About Evolution
 Georges
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Cuvier
Species can’t
change, but the
can go extinct
Fossils –
preserved remains
of living things
Catastrophism
• Natural disasters
shape Earth
• Cause species to
become extinct
Early Ideas About Evolution
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Hutton and Geological
Change
• Gradualism - geological
forces shape the earth
• Layers of rock form very
slowly
• These layers are
shaped by natural forces
• Due to the slow nature
of the forces, he
concluded Earth is very
old
Early Ideas About Evolution

Lyell’s Principles of
Geology
• Uniformitarianism
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To understand the
past, you have to
look in the “now”
• Earth process
Volcanoes
 Earthquakes
 Erosion
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Darwin’s Observations
Biodiversity –
The variety of
living things in life
 Evolution –
change over time

15-1 Life’s Diversity
 Voyage
of the
Beagle
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The Beagle was
British Naval ship
 Charles Darwin
• The father of
evolution
Darwin’s Observations
• As a member of
H.M.S. Beagle
Darwin collected
animal and plant
specimens
 These specimens
were later used to
create the theory of
evolution

Darwin’s Observations
–
difference in
physical traits
 Variation
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He found 68
different species
of beetles in one
day in a Brazilian
forest!
Found variations
when traveling
from place to
place
Darwin’s Observations
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Patterns of Diversity
• Types of animals in
similar places
• Ways that animals
reproduce
• Ways that animals
survive
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Adaptation – feature
that makes an
organism better suited
to its environment
Darwin’s Observations
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Living Organisms
and Fossils
• Darwin found
Glyptodon
• Rationalized that
extinct animals
looked much like
existing animals
Darwin’s Observations
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The Galapagos Islands
• A group of islands
northwest of South
America
• Darwin spent a lot of
time collecting there:
Iguanas
 Birds
 Tortoises
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Darwin’s Observations
Darwin’s Observations

The Journey Home
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Darwin observed that the
characteristics of many
animals and plants varied
noticeably among the
different islands of the
Galapagos.
According to this
hypothesis, these separate
species would have
evolved from an original
South American ancestor
species after becoming
isolated from one another.
Theory of Natural Selection
 Inherited
Variation and
Artificial Selection
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Variation within
domesticated species
species
• Breeders select
characteristics they want
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Pigeons
• Heritable
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For variations to be bred for
characteristic must be able to
be passed on
Theory of Natural Selection

Survival of the Fittest – individuals that
can survive and reproduce
• This is also called Natural Selection
Theory of Natural Selection
 Population
Growth
Malthus - 1798
 A population can
not grow forever

• Food
• Space
Theory of Natural Selection
 Evolution
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Struggle for
Existence
• Members of one
species compete
with each others
(populations) for
resources
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Food
Living Space
• Predators that are
the fastest or are
adept hunters will
be more
successful
Theory of Natural Selection
 The
reason for a
structure or feature
is because of
adaptations
 Ultimately,
natural selection
results in either
an organism
changing traits,
OR it dies
Theory of Natural Selection
 Alfred
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Wallace
Developed a
similar theory
Sent his
manuscript to
Darwin
Wanted to
publish the same
findings Darwin
had
Theory of Natural Selection
 Publication
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On the Origin of
Species
Darwin was
nervous about
publishing
It challenged
every
fundamental
scientific belief
Theory of Natural Selection
Four
main principles of Natural
Selection
Variation
 Overproduction
 Adaptation
 Descent with modification
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Theory of Natural Selection
 Variation
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Exist in all
populations
Result from
differences in
genetic make up
• Parents
• Mutations
Theory of Natural Selection
 Overproduction
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Produce more
offspring
• More chance for
survival
• Increase
competition
Theory of Natural Selection
• Adaptation
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An inherited trait that
improves the organism’s
chance of survival
Successful adaptations
make animals better
suited to their
environment
Adaptations can be
anatomical, structural,
characteristics,
physiological, or functions
Theory of Natural Selection
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Descent with
modification
• These adaptations will
lead to different
species over time
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Different:
• Structures
• Niches
• Habitats
Theory of Natural Selection
• Common descent

All living things have a common ancestor
Theory of Natural Selection
Theory of Natural Selection
• Fitness - the ability of an individual to
survive and reproduce
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Fitness happens because of adaptations
Theory of Natural Selection
 The
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Grant’s
Studied finches
on Daphne Major
1977 Drought
Reduced the
number of seeds
Drop in species
numbers
Theory of Natural Selection
 Grant’s
predicted a trait already in
the population would survive
 This was passed on to future
generations
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Increase in numbers
 As
environments change,
different traits become beneficial
Theory of Natural Selection
 Adaptations
and
Compromise
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Some
adaptations
become new
functions
• Panda thumb
Evidence of Evolution
 Fossil
Evidence
Bone structure, age,
location of discovery
 Fossils found in
deeper layers are
older than more
superficial layers
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Evidence of Evolution
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Geographic Distribution
• Species move from place
to place
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Ancestral species to
islands
Certain traits may be
beneficial when moving
• Ex. Finches
• Biogeography
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Study of the distribution of
organisms around world
Evidence of Evolution
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Similarities in
Embryology
• Crab and barnacle
larvae
• Vertebrate embryos
look very similar early
in development
• Evidence for common
descent
Evidence of Evolution
Evidence of Evolution

Homologous Body
Structures
• Structures that come
from the same
embryonic tissues
• Homologous
structures – bat wing
and human hand
• Analogous
structures – bird wing
and insect wing
Evidence of Evolution
 Vestigial
organs – organs
with little to no
function

Natural selection
has caused the
organ to shrink
or “disappear”
Evolutionary Biology Today
 Paleontology
Study of fossils
 No fossil
evidence to
contradict
evolution has
been found
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Evolutionary Biology Today
Molecular
and Genetic
evidence
DNA sequencing
 Pseudogenes
 Homeobox genes
 Protein comparisons
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Evolutionary Biology Today
 Evolutionary
biology is a fast
growing field
New technology
 New discoveries
 Benefits?
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• How does the idea of a common
ancestor help understand new
diseases?