Name: ___________________
Period:____
History of Biological Diversity
Evolution: Darwin’s travel
Developing the Theory of Evolution
The Galápagos Islands
Darwin noticed that the different islands all seemed to have their own, _________ different
varieties of animals.
Somewhat similar species that suited their _________________ environment.
Origin of Species: _________________________
 In 1859 On the Origin of Species presented evidence and proposed a mechanism for
evolution that he called __________________ ________________.
Today, scientists use _______________ to mean cumulative change in a group of
organisms through time.
Natural selection is _____ synonymous with evolution – it is a _________________ by
which evolution occurs.
Peppered Moth: Natural Selection
• The light colored form was the predominant form in ___________ prior to the
Industrial Revolution.
•
•
th
Around the middle of the 19 century the darker form began to appear. It was first
reported in 1848. By 1895 _______ of the moths in Manchester were the dark variety.
In recent years, the burning of cleaner fuels and Clean Air regulations has reduced
the pollution there and the lighter colored moths have increased in numbers.
Types of Selection
a. ____________ _____________ – humans select for variations
in plants and animals that they find useful.
b. _____________ ___________also means “Survival of the Fittest”.
- Fitness in this sense does ______ mean strongest.
- Fitness in Darwin terms means reproduction. The one who ____________ long enough
to reproduce the most is the one with the ________________ fitness.
Types of Natural Selection
Evolution acts on the phenotype of the individual, not the genotype.
There are 4 types of selection that can occur on a population.
1. Directional Selection
– when individuals at _________end of the curve have a higher fitness than individuals in the
middle or at the ___________ end of the curve.
1
 2. Stabilizing Selection
 – when individuals near the _____________ of the curve have higher fitness than individuals
at either end of the curve, narrowing of the graph.
3. Disruptive Selection
– when individuals at either end have a higher fitness and individual near the _____________ of
the curve are selected against.
Over time with enough selection a population can go through genetic drift.
a. ____________ _________________ – random change in allele frequency.
4. Sexual Selection: the ability to attract a ______________
Support for Evolution
Evidence for evolution comes from:
1. The ____________ record: remains in layers of rock
2. Comparative ________________
a. ______________ Structures
b. ______________ Structures
c. _______________Structures
3. Comparative _______________________
4. Comparative _______________________
5. ___________________ distribution
1. Support of Evolution: Fossil Record
• Fossil Record – Fossils are the remains of ancient organisms found in
________________ of rock in the Earth.
• The layers of rock tell the _____________ of the Earth, while the fossils found within the
rock tell a history of life.
• The fossils are thought to be the _________ _________ as the rock they are found in.
2
Researchers consider __________ major classes of traits when studying transitional
fossils:
• __________ traits are newly ______________ features, such as feathers, that do
not appear in the fossils of common ancestors.
• __________ traits are more ______________ features, such as teeth and tails, that
do appear in ancestral forms.
•
2. Support for Evolution: Comparative Anatomy
•
A. Homologous structures are anatomically similar ________________ inherited from a
common _______________.
• Similar _____________ with ________________ function (similar bones)
• (common ancestor)
•
•
•
•
•
B. Analogous structures can be used for the same ____________ and be
superficially similar in construction, but are ______ inherited from a common
ancestor.
Structures are ______________ but have _____________ function
C. Vestigial structures are structures that are the _____________ forms of functional
structures in other organisms.
Evolutionary theory predicts that features of ancestors that __________ longer
have a function for that species will become _____________over time until they
are lost.
3. Support for Evolution: Comparative embryology
•
Embryos of many animals with back-bones are very __________________.
4. Support for Evolution: Comparative Biochemistry
________________ ancestry can be seen in the complex metabolic molecules that many different
organisms share.
The more ______________ related species are to each other, the greater the biochemical
similarity.
Similarities in _________ and protein sequences suggest relatedness.
5. Support for Evolution Geographic distribution
The distribution of ______ and animals that Darwin were what first suggested evolution to him.
3
The distribution of plants and animals around the world is studied in the field of ____________.
Evolution is linked to migration patterns, climate, and geological forces (such as plate tectonics).
_________________- an inherited trait that increases a population’s chance of survival and
reproduction in a particular environment
_______________ is a measure of the relative contribution an individual trait makes to the next
generation.
The better an organism is _______________ to its environment, the greater its chances of
survival and reproductive success.
Through _______________, populations often become suited to a specific job called a niche.
•
1. niche – the role a population plays in a habitat
- job, profession, role
•
2. Competition arises when 2 populations ____________ the same niche.
Adaptation
Types of adaptations
________________ is a suite of morphological adaptations that allow an organism to blend into
its environment.
______________ is a type of morphological adaptation where a species evolves to resemble
another species.
Antimicrobial resistance develops in some bacteria in response to sub-lethal exposure to
__________________.
Population Genetics - study of the traits in a population
A. Population – a group of interbreeding organisms (a species) living in a ______________ area
B. Gene Pool – ____________ genetic material of all the members of a population
C. Gene Flow-the transfer of allele or genes from __________ population to ___________
D. Genetic Drift- any change in the allelic frequency in a population that results from
__________.
E. Allele – forms that a _________ can take
F. Allele Frequency – the number of each allele for a trait
 This “changing of the gene pool” (allele frequency) has a name —› Evolution.
 Evolution – the changes in the gene pool of a population over time.
Speciation – formation of a _______ species
 Reproductive Isolation
- 2 or more species _________ _________ interbreed
Prezygotic: Its happens ___________ fertilization: different reproductive times and different
mating songs.
Postzygotic: Its happens ___________ fertilization: fertilization has occurred but results in
sterile offspring (Mule)
4
 1. Behavioral Isolation occurs when 2 populations are capable of interbreeding
but have differences in _________ ________ or breed at different ___________
 2. Geographic /Allopatric Isolation: 2 populations are separated by
_____________barriers ●examples: rivers, mountains, bodies of water
Types of Evolution
 Convergent Evolution: less alike to __________ alike
 Divergent Evolution=Adaptive Radiation: more alike to _________ alike
 Coevolution: evolve _____________
 Punctuated equilibrium: happens in _________ period of time
Convergent Evolution:
 Occurs when ______________ organisms that live in ____________ environments
become more alike in appearance and _______________.
 Less alike to more alike
 Examples: - Bird wings/insect wings
- Shark fins/dolphin fins
Divergent/Adaptive Evolution
 __________ species give rise to _______
species
 More alike to less alike
 Also known as adaptive radiation.
 Examples: - Darwin’s Finches.
- Brown bears and polar bears
Co-evolution
 Co-evolution occurs when, ___________or more organisms evolve _____________.
Gradual equilibrium
 Predicts that little of evolutionary change takes place in _________ gradual steps
Punctuated equilibrium
 predicts that a lot of evolutionary change takes place in ____________ periods of time
tied to speciation events.
5
6