4/13/2020
Today’ Agenda:
Journal Question: a. What is an adaptation?
*1. Lecture V: Natural Selection &
Adaptations ( slide 37 )
2. Biome Presentations
3. Homework: Study Guide
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Lost…..
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Lost!
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Lost!
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Get Help
Tutoring Available:
-Study Center (lunch, 7 th period, after school)
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Feeling Lost….
1. Get Help!
2. Tutoring Available in the Study
Center: J109
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Feeling Lost… In Biology
If you are getting a “D” or lower go to tutoring and receive ten points added to your grade.
When :
(1) Before School
(2) Nutrition
(3) Lunch
(4) Period 7 & After School
Where: J109
Needs: Tutoring Form
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By Dr. Rick Woodward
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What you should know for Exam I
(That is not on the study guide)
A. Geographic Isolation
B. Adaptive Radiation
C. Gene mutation has adaptive value….
D. Today’s lecture on natural selection and adaptations
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Geographic Isolation
A. Geography separates a species from reproducing.
(1) Example: The Grand
Canyon separating squirrel populations
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Adaptive Radiation
A. Diversity of finch species found on the Galapagos
Islands. (Adaptations)
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An Adaptation…
A. Big Mamma …Blending in….
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Darwin’s Theory of
Natural Selection
(1) In nature there is a tendency toward overproduction .
a. Examples: mice , watermelons , ants , fish , and mosquitoes are all well-known overproducers .
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Darwin’s Theory of
Natural Selection
(2) Not all offspring that are produced survive . a. Example: many bacteria that are treated with antibiotics will die.
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How antibiotics destroy bacteria:
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Darwin’s Theory of
Natural Selection
(3) Variations exist in any population .
(4) Variations are inherited .
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Darwin’s Theory of
Natural Selection
(5) Those individuals with variations that are suitable for their environment will live longer and leave more offspring on average .
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Natural selection
Microevolution: change in allele frequency in a population
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In the Galapagos
A. Based on Darwin’s observations in the Galapagos :
1. Darwin’s described evolution as descent with modification .
structural or functional changes occur from one group of descendants to the next, and so on.
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In the Galapagos
2. Darwin performed extensive research on the island’s finch population . a. Studied finches structural modification
(bird’s beaks) to environment
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Natural Selection
& Adaptations

The leaf bug
A. An adaptation is a characteristic that helps an organism survive in its environment or reproduce.
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The Evolution of
Complex Adaptations
A. Adaptations in organisms you see today are the result of chance variations that arose at a particular time in the evolutionary history of that type of organism.
B. Example: The eye
(next slide)
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A Series of
Changes During the Evolution of the Eye
A. Simple animals such as flatworms have groups of light-sensitive cells to detect light .
B. More complex animals have visual systems that form images.
C. In mollusks the images are blurry .
D. The images are focused for a turtle.
E. The images are focused and enhanced by color in the eagle and many other vertebrates.
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Explaining the
Complexities of the Eye
A. Biologist know that the eye began only as a group of lightsensitive cells.
B. The ability to distinguish between light and dark was an advantage because it enabled organisms to avoid danger and exploit new food resources more efficiently than organisms without this adaptation.
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Explaining the
Complexities of the Eye
C. Later, over time, new variations arose that resulted in the formation of a simple lens providing a blurry image.
D. Seeing even a blurred image is an advantage over seeing no image at all .
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Explaining the
Complexities of the Eye
E. Later changes led to a sharpening of focus , and, probably at the same time, still other changes permitted color vision.
F. The structure becomes more adaptive and improves an animal’s chances of survival, and, therefore, the passing of its genes to offspring.
( natural selection )
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Types of Adaptations
A. Structural Adaptations
1. The most obvious adaptations are those involving structure or anatomy.
2. Traits such as the structure of a bird’s beak, the hoof of a horse, or the shape of a tooth are called structural adaptations.
3. Many obvious structural adaptations in animals are for obtaining food.
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Structural Adaptations
A. The neck of the
Giraffe
B. The slow hypothetical evolution: Response to
Acacia Trees
C. Neck increased in length to reach food in trees .
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Structural Adaptations that mimic the environment
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Structural Adaptations that
Mimic the Environment
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Structural Adaptation in the Angler Fish
A. Protruding from the top of the angler fish’s skull is a long filament that is broad and flat at its tip.
B. It hangs in front of the fish’s mouth and attracts prey, much like a fishing lure .
C. When the prey bites at the lure, the angler fish sucks the prey into its mouth.
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Deep Sea Hairy Angler Fish
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Physiological Adaptations
A. The enzymes needed for digestion, clotting of blood, or muscular contractions in animals fall into the category of Physiological
Adaptations .
B. Such adaptations have a chemical basis.
C. Other examples include the poison venom of a snake, the proteins used in a spider’s web, and the ink of an octopus.
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Behavioral
Adaptations
A. Organisms are also adapted in their responses to the environment.
B. Birds migrate in search of food , squirrels hunt and store nuts , wolves track their prey ,
C. Such responses are examples of behavioral adaptations .
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In-Class Assignment for next class session
1. Create an organism with:
(1) At least three structural adaptations .
(2) At least two physiological adaptations .
(3) At least two behavioral adaptations .
2. Draw this organism and explain how these adaptations benefit this being and allow it to compete and survive .
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