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Name: ________________________ Period:______ Unit Exam Date_____________

Unit 8: History of Biological Diversity

Developing the Theory of Evolution

Charles Darwin

Developed the _________________ Theory of _________________

_________________ of Evolution

Traveled around the world for 5 years on a ship called ______ ___________

_________________ animals and plants on the _________________ _________________

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.

6 Evidences (Support) for Evolution

Evidences 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

6. Mechanisms of Natural Selection

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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.

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. Support for Evolution: 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. Support for Evolution: 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.

Ex. Whales pelvis bone: no longer live on land

Human appendix: do not forage and eat as many plants

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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.

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).

6. Support for Evolution: Mechanism of Natural Selection

Natural Selection: _____________ ______________ (differences) in the __________ of a

______________ will cause individuals with “better” ______________ in an ______________ leave

______________ ______________ than other individuals.

“Survival of the fittest”= most ______________

Practice:

There are four female mice that live on a beach. The color of the sand is tan.

Color of fur Black Tan Tan and Black Cream

Age at death 2 months 8 months 4 months 2 months

Number of babies produced by each female 0 11 3 0

Running speed 8 cm/sec. 6 cm/sec. 7 cm/sec. 5 cm/sec.

What are the genetic variations of this mice population? ________________ & _________________

According to the definition given for fitness, which mouse would biologists consider the fittest? _____________________________

Explain why this mouse would be the fittest. _____________________________________________________________________

What adaptive trait do you think helped the ones who survived? ______________________________________________________

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Genetic Variation in a _______________ can lead to

________________!

Genetic _______________ produces different adaptations.

Allows a population to become _______________

_______________for their _______________ over time

(Change over time = _______________)

Peppered Moth: Natural Selection

• The light colored form was the predominant form in ___________ prior to the Industrial

Revolution.

• Around the middle of the 19th

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.

Example of natural selection leading to evolution: bacterial resistance to medicine

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.

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4 Types of Natural Selection (graphs)

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.

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 (create new species).

a. ____________ _________________ – random change in allele frequency.

4. Sexual Selection: the ability to attract a ______________

ex. Male peacocks needs to have colorful tail feather

to attract female mate.

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Adaptations

Adaptation- an ______________ trait that increases a ______________ chance of survival and

reproduction in a particular environment

Fitness- is a ______________ of the relative contribution an individual ______________ makes

to the ______________ generation.

The better an organism is ______________to its ______________, the greater its chances of

survival and reproductive ______________.

Through _______________, populations often become suited to a specific job called a niche.

1. Niche – the role a population plays in a habitat ex. job, profession, role

2. Competition arises when 2 populations ____________ the same niche.

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.

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 _____________.

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E. Allele – forms that a ___________ can take ex. fur color gene can be B (black) or b (white)

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: It happens ___________ fertilization:

different reproductive times and different mating

songs.

Postzygotic: It happens ___________ fertilization:

fertilization has occurred but results in sterile offspring

(Mule)

Behavioral Isolation *postzygotic occurs when 2 populations are capable of interbreeding but

have differences in ________________ _____________ or breed at different _____________

Geographic /Allopatric Isolation *prezygotic

2 populations are separated by

____________________barriers

examples: rivers, mountains, bodies of water

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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.