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THEORY OF
EVOLUTION
Chapter 16
Idea of Evolution
◦ Charles Darwin (1809-1882)
◦ English ________________
◦ Took a trip around the world on a ship called ________________
Mostly fascinated with the ________________ Islands
◦ Best known for his theory of ________________ by natural selection
Darwin’s Journey
◦ Began in ________________
◦ Sailed on a ship called the H.M.S. Beagle
◦ Five year voyage sailing around the coast of ________________
________________ and ________________
Observations Aboard the Beagle
◦ Darwin collected 68 species of ________________
◦ Wrote about the different characteristics of habitats and species
that live there
◦ Species vary ________________
◦ There are similar organisms around that world with similar ecological
________________
◦ Ex: Rhea birds in S. America and ________________ in Africa
Observation Aboard the Beagle
◦ Species vary ________________
◦ Related animals species often occupy different habitats within a
________________ area
◦ Ex: Tortoise ________________ ________________ among Galapagos
Islands
Observation Aboard the Beagle
◦ Species vary ________________ ________________
◦ Some fossils of ________________ animals were similar to living
species
◦ Ex: Armadillo ________________ compared to modern day armadillos
Darwin’s Findings
◦ Galapagos Islands
◦ Groups of animals ________________ from island to island
◦ Ex: tortoises on each island resemble each other but differ in the shape and
function of their ________________
◦ Ex: finches on each island resembled each other but differ in the shape and
function of their ________________
◦ Darwin believed these unique animals all came from a ________________
________________ and they changed/adapted to their environment
Idea of Evolution
◦ Evolution
◦ Development of new types of organisms ________________
________________
◦ Heritable ________________ in the characteristics within a
population from one generation to the next
Ideas of Darwin’s Time
◦ Scientists thought all species were ________________ and
unchanging
◦ The Earth was believed to only be a few ________________
(not billions) of years old
◦ During Darwin’s time, new research was being done to figure
out the ________________ of the Earth
Ideas that Influenced Darwin
◦ James Hutton was a geologist in 1700’s
◦ Made connections between mountains, valleys, and layers of
________________
◦ Believed the ________________ was older than thousands of
years -- a time so old for the human mind to image
◦ The Earth changes very ________________ and some layers
can accumulate as the environment is changing
Ideas that Influenced Darwin
◦ Charles Lyell was a English
________________ that believed the
Earth’s surface continues to change
◦ He explained that past processes that
occurred are still occurring now
◦ Ex: ________________ erupted in the past and still
today
◦ Published a great work called ________________
______ ________________ in 1830 that built on the
work of Hutton
◦ Darwin read this book while on his journey around
the world
Ideas that Influenced Darwin
◦ Jean-Baptiste Lamarck
◦ French naturalist that ________________ the idea that populations of
organisms change over time
Ideas that Influenced Darwin
◦ Proposed two hypotheses: Called Theory of ________________
________________
◦ Organisms could ________________ during their lifetime by using or not
using selected parts of the body
◦ Individuals could pass these ________________ traits on to their offspring
◦ Ex: Giraffes could ________________ their neck by stretching over a
period of time to get the height they needed to eat and survive and
then pass the longer neck trait to their ________________
Ideas that Influenced Darwin
◦ Thomas Malthus was an English economist in the 1790s
◦ Reasoned that if the human population grew continuously, there would not be
enough ________________ for everyone
◦ His reasoning explained why plants and animals produced more a high amount
of ________________ since a portion will not ________________ due to
environmental factors
◦ Ex: Maple tree produces ________________ of seeds each summer
◦ Ex: Oysters produce ________________ of eggs each year with the
understanding that only a fraction will survive
Darwin’s Ideas
◦ Around the same time Darwin and Wallace formed ________________ to
explain evolution
◦ Darwin was able to publish his book first called _______ _______
_____________ ______ ____________ in 1858
◦ Book explained how evolution occurs by means of ________________
________________
Artificial Selection
◦ Darwin studied ________________ breeders
◦ Farmers would select to breed only _____________ with the largest fruit,
or the _____________ that produce the most milk
◦ Darwin called this process ________________ ________________
◦ Nature provides the ________________, and humans select hose they
find to be useful and allow them to breed and pass on
________________ to offspring
Evolution by Natural Selection
◦ Mechanism from descent with
_____________
◦ 1. Struggle for Existence
◦ Organisms produce more offspring
than can _____________
◦ Ex: grasshoppers lay over 200
_____________ at a time, but only
a fraction survive
◦ 2. Variation and Adaptation
◦ Traits vary within a species and
their environment called
_____________
◦ These adaptations help increase
_____________ to survive
◦ Ex: _____________ with coral
snake and scarlet snake
Natural Selection (cont’d)
◦ 3. Survival of the Fittest
◦ Organisms best _____________
for an environment will survive
best and _____________
◦ The ability for an organism to
_____________ and pass on
adaptations
◦ 4. Natural Selection
◦ Process by which organisms with
_____________ most suited to
their local environment survive and
leave more _____________
◦ Organisms _____________ their
mate based on desired traits
Common Descent
◦ Idea that every species must have ___________ by reproduction
from pre-existing ___________ that arrange over time
◦ Ex: finch ___________ at Galapagos
◦ All species – living and extinct – are descended from ancient
_____________ ancestors
Transitional Species
◦ Organisms with features that are _____________
hypothesized ancestors
Age of the Earth & Fossils
◦ Noted that fossils of extinct
animals _____________ living
species
◦ Relative Age
◦ Age _____________ to other fossils
in order of old to young
◦ Absolute Age
◦ Using radioactive dating to get
_____________ _____________ age
Age of the Earth and Fossils
◦ Age of the Earth
◦ Geologists are certain based on
evidence via radioactive dating to
indicate the Earth is about _______
_____________ years old
◦ Fossils
◦ _____________ of an organism that
died long ago
◦ Many fossils form a series that can trace
back to an ancient extinct
_____________
◦ Superposition
◦ Idea that _____________ form in layers
where the layers closest to the _______
are the younger than below
Biogeography
◦ Study of where organisms live _____________ and where they
and their ancestors lived in the _____________
◦ Darwin used this method when exploring islands and observed
_____________ vary based on their _____________
◦ Closely related but Different
◦ Darwin believed that the finches of the _____________ all came
from a common ancestor in the _____________
◦ Over time, _____________ selection produced a variation of species
of finches
◦ Distantly Related but Similar
◦ Darwin noted that organisms that are _____________ related and
inhabit similar environments have _____________ qualities
Anatomy and Embryology
◦ Anatomy: study of the __________
◦ Embryology: study of
_____________
◦ Homologous structures
◦ Anatomical structures that originated
from the _____________ common
_____________
◦ Ex: bones in arms of humans,
penguins, alligator and bat
◦ Related _____________ but
_____________ may differ
Anatomy and Embryology
◦ Analogous Structures
◦ When structures have similar
_____________ , but did not
develop the same way
◦ Ex: wings of bat vs. bird
◦ Vestigial Structures
◦ Organs that no longer serve a
_____________ in an
organism
◦ Ex: human tail bone,
appendix
Anatomy and Embryology
◦ Embryology
◦ Similar patterns of
embryological
_____________ provide
further evidence that
organisms have descended
from a _____________
ancestor
◦ Many animals look
_____________ during
development and produce
_____________ tissue
Genetics and Molecular Biology
◦ At the molecular level, the _____________ _____________
and homologous molecules provide _____________ of
common descent
Phylogeny
◦ _____________ among
groups of organisms
◦ Can make a “__________”
of animals evolved
◦ Trunk of the tree would
represent species that are
_____________ related
◦ Branches represent a
_____________ population or
lineage
Caribbean Anole Lizard
◦ Found in the Caribbean islands of Cuba, Hispaniola, Jamaica, and
Puerto Rico
◦ Each lizard species body type differs by their habitat
◦ Ex: stocky body and long legged lizards are best adapted for tree truck environments,
slender bodies and long tails are best adapted for grassy environments
◦ Hypothesis #1: An ancestral anole species specialized for living on
twigs originally lived on one island and later migrated to other islands
OR
◦ Hypothesis #2: Each twig-dwelling species evolved independently on
each island from distant ancestor anole species
Evolution in Action
◦ Biologists tested the hypothesis by comparing
_____________ from the various species
◦ DNA evidence supported hypothesis 2 that each lizard evolved
_____________ on each island
◦ Convergent Evolution
◦ Process by which _____________ species
evolve _____________ traits
◦ Ex: twig-dwelling species came from
different ancestors but evolved similar
adaptations to their environment
Divergence & Radiation
◦ Divergence evolution
◦ Process by which the descendants of a _____________
ancestor diversify into species that each fit
_____________ parts of the environment
◦ Ex: All breeds of dog share a common ancestor with wolves
Divergence & Radiation
◦ Adaptive Radiation
◦ Pattern of diversity when a new population in a new _____________
undergoes divergent evolution
Coevolution
◦ Evolution is on-going and many species may evolve
_____________
◦ Coevolution
◦ When _____________ or more species have evolved adaptations to
each other’s _____________
◦ Ex:
◦ Predator/Prey Interactions
◦ Introduction of new species
◦ Creating antibiotics