Name:_____________________________________________________________Period:_____________

Natural Selection Notes

TEKS 7C: Analyze and evaluate how natural selection produces change in populations, not individuals

TEKS 7D: Analyze and evaluate how the elements of natural selection, including inherited variation, the potential of a population to produce more offspring than can survive, and a finite supply of environmental resources, result in differential reproductive success

TEKS 7E: Analyze and evaluate the relationship of natural selection to adaptation and to the development of diversity in and among species

Developing the Theory of EvolutionThe Galápagos IslandsDarwin noticed that the different islands all seemed to have their own, _________ 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 __________________ ________________.

Natural Selection

____________ _________________ is a process of elimination.

ORGANISMS THAT HAVE _________ THAT ARE BEST _____________ FOR THE CURRENT ENVIRONMENT ARE THE ONES THAT ___________ TO BREED AND PASS ON THEIR __________ TO THE NEXT GENERATION, CAUSING A CHANGE IN THE OVERALL ___________________.

Organisms not possessing the beneficial traits either die or don’t have as many offspring.

Natural Selection is _________________ of the fittest

Biological ____________- ability of an organism to survive AND reproduce (pass on its genes)

Main Points of Natural Selection1. Genetic __________ is present in the population and it is inherited (passed to offspring)

-Mutations: Changes in the DNA-Meiosis: crossing over -Random mate selection & fertilization

2. Living Things _________________ Offspring (not all survive)

3. Competition for ___________ Resources

4. Survival of the “_____________”

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Name:_____________________________________________________________Period:_____________

Differential Reproductive Success

Adaptations-a ____________ or the process of change by which an organism or species becomes better suited to its environment.

Types of adaptations2

Natural Selection

Name:_____________________________________________________________Period:_____________

_________________ 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. ______________ ______________ develops in some bacteria, making them able to survive antibiotic treatments

Peppered Moth: Natural Selection• The colored form was the predominant form in England 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 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.

Mechanisms of Evolution and How Evolution Occurs TEKS 7F: Analyze and evaluate the effects of other evolutionary mechanisms, including genetic drift,

gene flow, mutation, and recombinationTEKS 7B: Analyze and evaluate scientific explanations concerning any data of sudden appearance of

stasis, and sequential nature of groups in the fossil record

5 Mechanisms of Evolution

1. Recombination-Crossing over leads to __________ _____________.-Crossing over is why siblings can have the same parents but

still may look very ________________(except for identical twins etc.).

2. Mutation-Mutation creates ______________________ -new mutations are constantly appearing-Mutation ___________________________________________

-changes amino acid sequence-changes protein’s structure and function-changes in protein may change phenotype & therefore

change fitness

3. Natural Selection (see natural selection notes)4. Gene Flow

-_____________ of individuals & alleles ____ &_____ of populations-seed & pollen distribution by wind & insect-migration of animals

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Name:_____________________________________________________________Period:_____________

-sub-populations may have different allele frequencies -causes ___________________ across regions-reduce differences between populations

5. Genetic Drift-Effect of _______________________

a. __________________-small group splinters off & starts a new colony-Skews the gene pool of the new population

b. __________________ -Some factor (disaster) reduces population to small number & then population recovers & expands againAlleles lost from gene pool, ______________ the gene pool

How Evolution Occurs

There are two scientific theories regarding how evolution occurs.

Punctuated Equilibrium:

Species go through _______ periods of ________ change and then have ________ periods of ________ change.

Gradualism: Species _______________ undergo changes that leads to speciation.

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