Exam 2 Lecture 9
UIC BioS 101 Nyberg
1
Adaptation
Traits that function to increase survival or reproduction and are due to genes (i.e., are heritable) are called adaptations.
Speaker Notes:
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Traits have to WORK and be transmitted to offspring.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Reading
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The reading for today’s lecture is p. 913 – 916, & 921-926 in chapter 41.
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Animal form and function are the product of many years of evolution, and are often considered in the evolution section of books.
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Adaptations are explained by stories.
Speaker Notes:
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Stories explain how things work, how their function is better than some alternative.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Questions
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How are Oryx able to live in the desert where most animals can’t?
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How can the variety of fish mouths be explained?
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How do organisms hide?
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How does function change with size?
And many others.
Speaker Notes:
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Each of these questions can be answered with a story.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Understanding
adaptation
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For each question one can do studies from which one learns something about function. This information about ‘mechanisms’ is woven into a story that explains how the organism functions.
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Metabolic water offers an explanation of how an organism can survive in desert (=without drinking water).
Speaker Notes:
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Not all questions have clear answers.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Adaptation vs Acclimatization
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Changes that increase function of an individual (such as exercise), but can not be transmitted to offspring are called acclimatization.
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Adaptation is reserved for increases in function that are the result of genetic change of the population.
Speaker Notes:
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vs = versus = contrast to
Education increases function and can not be transmitted via genes but it is NOT normally described as acclimatization.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Adaptation as process
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Biologists call the processes of becoming adapted adaptation, so the word can be a verb or a noun.
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Though adaptation requires changes in genes, the stage of the process where the genes are polymorphic is rarely observed.
Speaker Notes:
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Existing structures/conditions are called adaptations by biologists.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Structure and Function
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Consider the mouth of a fish.
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The mouth performs functions that are part of breathing and prey capture and perhaps other activities.
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The ‘best’ arrangement for breathing may not be the ‘best’ for capturing quick prey, the conflict among functions results in a ‘trade-off’.
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Speaker Notes:
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Trade-offs are a way of talking about compromise between different functions.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Ways fish feed
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Suction is an important component of feeding of most fish.
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The mouth cavity expands and water rushes in.
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Only a few fish use teeth to capture prey
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Filtering small organisms from water works for some fish
Speaker Notes:
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Catching prey in water is different than catching prey in air.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Alligator Gar
uses its teeth
Speaker Notes:
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Have you seen a gar in the wild?
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Largemouth bass
use suction and ‘swimming over’ prey
Speaker Notes:
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Crayfish are among the favorite food of bass.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Paddlefish,
a filter feeder
Speaker Notes:
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‘filtering’ water is common in aquatic organisms.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Parrotfish
have jaws strong enough to eat coral
Speaker Notes:
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Fish prey capture options are tremendously diverse.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Seahorse
mouth is a narrow tube
Speaker Notes:
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A very interesting salt water fish in which the male “incubates’ the offspring.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Camouflage
Speaker Notes:
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Can you see the frog in this picture? What about the woodcock in the BioS 101 Nyberg main page.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Camouflage
Speaker Notes:
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A baby woodcock.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Camouflage and lack thereof, Biston
Speaker Notes:
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Each picture has a ‘light’ moth and a ‘dark’ moth.
The dark form is known as industrial melanism because it arose when soot covered trees in England.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Area and Volume
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The size of organisms and cells plays a big role in how they function.
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Volume increases proportional to the cube of length, i.e., l3.
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Surface area increases proportional to square of length, i.e., l2.
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As cells get bigger it is harder to get the materials the cytoplasm needs thru the cell membrane.
Speaker Notes:
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Allometry is the study of how relationships change with size.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Increasing surface area
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Large individuals have a variety of ways to increase the surface area in tissues and organs.
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Flattening
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Folding
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Branching
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All organs of the body have some features to increase rates of exchange of material across membranes.
Speaker Notes:
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How much surface area does a person have?
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Efficiency is not always increased by evolution
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Salamanders and other ‘cold blooded’ organisms are more efficient in converting the food they eat into biomass than are the ‘warm blooded’ birds and mammals, yet amphibians and reptiles have largely been replaced by mammals and birds in most ecosystems.
Speaker Notes:
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Evolution does not necessarily increase all functions of systems.
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Mammals vs amphibians
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Mammals use a much smaller percent of the energy that they gather for reproduction and growth, but because they can gather more food per gram of mass (and perhaps for other reasons) mammal populations can grow faster than amphibians.
Speaker Notes:
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How can the ‘efficiency’ of growth be improved?
Exam 2 Lecture 9
UIC BioS 101 Nyberg
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Vocabulary
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Adaptation
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Form and function
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Acclimatization
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Polymorphic
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Trade-off
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Suction
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Diffusion
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Allometry
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Efficiency
Speaker Notes:
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