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The Puzzle of Life’s Diversity, Ch 15
Voyage of the Beagle
–In 1831, Darwin set sail from England aboard the ___________________ for a voyage around the world.
–Darwin went ashore and collected ____________ and ________________ _______________ for his collection
and filled many notebooks with his ____________________ and thoughts.
–During his travels, Darwin made numerous observations and collected evidence that led him to propose a
hypothesis about the way life changes over time.
-That __________________ has become the _________________________________.
- Evolution is the process by which _____________________ have descended from _________________.
–A ______________________________ is a well-supported testable explanation of phenomena that have
occurred in the ________________________________.
Darwin’s Observations
–Darwin observed that many plants and animals were ________________________ to the environments they
inhabited.
–He was impressed by the ways in which organisms __________________ and _________________________.
–Darwin was puzzled by where different species lived and did not live.
Ideas that Shaped Darwin’s Ideas
1. ____________________
–During the 18th and 19th centuries, ____________________________________________ gathered information
suggesting: Earth is VERY old, and the processes that changed the earth in the past are the same processes
that operate in the present (_____________________________).
–_____________________________________________________________________________.
This understanding of geology influenced Darwin:
–If the Earth could change over time, life might change as well.
–It would have taken many years for life to change in the way Lyell suggested.
This would have been possible only if the ____________________________________.
2. ____________________________________________________________
Jean-Baptiste Lamarck (1744-1829) recognized that:
–_________________________ have changed over time.
–all species were ___________________ from other species.
–organisms were __________________ to their environments.
Lamarck’s Assumptions
a. ________________________________- organisms change because they “want” to better themselves
Example: ____________________________________________________________________________
b. _______________________________: organisms could alter their appearance by using them or not using
them
c. ________________________________: if an animal acquired a trait during their lifetime, they could pass on
that trait to their children
Example: ____________________________________________________________________________
–Lamarck’s hypotheses of evolution are incorrect in several ways.
Lamarck did not know:
–how traits are _________________________.
–that an organism’s behavior has no effect on its ______________________________.
3. _______________________________________:
–In 1798, ______________________________ published a book in which he noted that babies were being born
faster than people were dying.
–The only forces he observed that worked against this growth were ____________________________________
–Malthus reasoned that if the human population continued to grow unchecked, sooner or later there would be
______________________________________ and ___________ for everyone.
–When Darwin read Malthus’s work, he realized that this reasoning applied to plants and animals.
Natural Selection and Evidence for Evolution, Ch15
Name:____________________
Publication of On the Origin of Species
 In ____________, Darwin published his book, On the Origin of Species. In his book, Darwin:
o Proposed a ________________ for evolution called natural selection.
o Presented _________________that evolution has been taking place for __________________ of
years and continues in all living things.
Inherited Variation and Artificial Selection
 Members of each species ___________ from one another in important ways.
 In Darwin’s day, __________________ were thought to be unimportant, minor __________.
 Darwin noted that plant and animal breeders would breed only the largest hogs, the fastest horses, or the
cows that produced the most milk.
 Darwin termed this process _______________________ ______________________.
Evolution by Natural Selection
 Darwin compared processes in ________________ to artificial selection.
 He developed a scientific _________________ to explain ______ evolution occurs.
 Darwin realized that high ____________ rates and a ________________ of life's basic needs would force
organisms to __________________ for resources.
 The ____________________________________________ means that members of each species
compete regularly to obtain food, living space, and other necessities of life.
Survival of the Fittest
 The ability of an individual to survive and reproduce in its specific environment is ________________.
 Darwin proposed that fitness is the result of _______________________.
 Individuals with characteristics that are not well suited to their environment either _____________ or leave
few _____________________.
 Individuals that are better suited to their environment _________________ and ____________________
 Darwin called this process ____________________________________________.
 Because of its similarities to artificial selection, Darwin referred to the survival of the fittest
______________________________.
 In natural selection, ___________________________________________________________________.
Summary of Darwin’s Theory
1. There is _______________ among populations.
 Variations are ____________________ and passed from parent to offspring
2. Some variations are ___________________- favorable variations improve the ability to function.
3. Not all young produced in each generation can __________________.
4. Individuals that survive and reproduce are those with ______________________________.
Evidence of Evolution
1. ______________________________
 Darwin saw fossils as a _____________________ of the history of life on Earth.
 By comparing fossils from _______________ rock layers with fossils from ______________________
layers, scientists could document that life on Earth has _____________________ ________ _________.
2. ______________________________
 Structures that have different mature forms but develop from the same ______________________ tissues
are called ___________________________________.
 Similarities and differences in homologous structures help biologists __________________ animals
according to how recently they last shared a common ____________________________.
 The organs of many animals are so reduced in size that they are just vestiges, or traces, of homologous
organs in other species. These organs are called _________________________________________.
3. _________________________________
 The early stages, or ________________, of many animals with ____________________ are very similar.
 The same groups of embryonic ________________ develop in the same ___________________ and in
similar ______________________________ to produce the tissues and organs of all vertebrates.
4. _________________________________
 ____________________ is a protein involved in using energy in the cell. Over time, _________________
in the DNA sequence occur. As a result, the amino acid sequence of Cytochrome C also changes.
 _____________- branching diagram showing relationship of animals based on shared anatomical features
Evolution of Populations, Ch 16
Where do variations come from? _______________________ and _______________________
Natural Selection and Populations
______________gene traits- controlled by 1 gene.
______________ trait- controlled by 2 or more genes.
-______________________________: those at _________________________________________________
-______________________________: those at _________________________________________________
-______________________________: those at _________________________________________________
Speciation
- Natural selection and chance events can change the relative ____________ of alleles in a ____________ and
lead to speciation. ______________________ is the formation of new species.
-A _________ is a group of organisms that breed with one another and produce ___________ _____________.
What factors are involved in the formation of a new species?
-The ________ __________ of two populations must become ______________ for them to become new species.
Reproductive isolation- When members of the two populations can’t breed with each other and produce fertile
offspring, ___________________ ______________ has occurred
Isolating Mechanisms: How can reproductive isolation occur?
1. ______________ ______________: when two populations are capable of interbreeding, but have differences
in courtship rituals or other reproductive behaviors. Ex: Meadow Larks...
2. _______________ _______________: two populations are separated by _______________ ____________,
like rivers, mountains, or bodies of water. Ex: Grand Canyon Squirrels
3. ___________ _____________: when two or more species reproduce at ____________ __________ (ie.
different months or seasons). Ex: Leopard Frog, American Bullfrog
Genetic Drift- ______________________ in allele frequency that occurs in ___________ populations.
1. ________________________- new population started by a small group, that can skew the gene pool.
2. ________________________- when a large population is reduced by disaster, leading to loss of variation
Patterns of Evolution
1) Mass Extinction
Causes of Mass Extinction:
- _________________________- rapid changes in early weather patterns, ex: Ice age
-_________________________- sudden oozing of millions of cubic meters of lava, releasing poisonous gasses
-_________________________- Meteors or asteroids impacting the earth.
2) Adaptive Radiation:_______________________________________________________________________
_________________________________________________________________________________________
3) Convergent Evolution:_____________________________________________________________________
_________________________________________________________________________________________
4) Coevolution:_____________________________________________________________________________
_________________________________________________________________________________________
5) Punctuated equilibrium:_____________________________________________________________________
_________________________________________________________________________________________
2) Gradualism:_____________________________________________________________________________
_________________________________________________________________________________________
Strata- ___________________________________________________________________________________
Geologic Time- ____________________________________________________________________________
There are four eras:
Precambrian (______ billion- ______ million years ago)
Paleozoic (__________________ million years ago)
Mesozoic (____________________ million years ago)
Cenozoic (____________________________________)